Package: guix-patches;
Reported by: unmush <unmush <at> proton.me>
Date: Fri, 29 Nov 2024 17:46:03 UTC
Severity: normal
Tags: patch
Merged with 57625
Done: Efraim Flashner <efraim <at> flashner.co.il>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Efraim Flashner <efraim <at> flashner.co.il> To: 74609 <at> debbugs.gnu.org Cc: aaron.covrig.us <at> ieee.org, ludo <at> gnu.org, unmush <unmush <at> hashbang.sh>, richard <at> freakingpenguin.com, unmush <at> proton.me, janneke <at> gnu.org Subject: [bug#74609] [PATCH 18/21] gnu: Add mono-pre-5.10.0. Date: Mon, 16 Dec 2024 19:26:41 +0200
From: unmush <unmush <at> hashbang.sh>
* gnu/packages/dotnet.scm
(mono-pre-5.10.0-external-repo-specs, mono-pre-5.10.0): New variables.
* gnu/packages/patches/mono-mcs-patches-from-5.10.0.patch: New patch.
* gnu/local.mk (dist_patch_DATA): Register new patch.
Change-Id: Ie78dce071032b6743b6e4c2eb58e43bc89e6a1d1
---
gnu/local.mk | 1 +
gnu/packages/dotnet.scm | 73 +
.../mono-mcs-patches-from-5.10.0.patch | 4218 +++++++++++++++++
3 files changed, 4292 insertions(+)
create mode 100644 gnu/packages/patches/mono-mcs-patches-from-5.10.0.patch
diff --git a/gnu/local.mk b/gnu/local.mk
index 2b1a6f7c782..c58bfe73cdb 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1829,6 +1829,7 @@ dist_patch_DATA = \
%D%/packages/patches/mono-4.9.0-fix-runtimemetadataversion.patch \
%D%/packages/patches/mono-5.4.0-patches.patch \
%D%/packages/patches/mono-5.8.0-patches.patch \
+ %D%/packages/patches/mono-mcs-patches-from-5.10.0.patch \
%D%/packages/patches/mosaicatcher-unbundle-htslib.patch \
%D%/packages/patches/mrrescue-support-love-11.patch \
%D%/packages/patches/mtools-mformat-uninitialized.patch \
diff --git a/gnu/packages/dotnet.scm b/gnu/packages/dotnet.scm
index 82fc2033707..414e955340f 100644
--- a/gnu/packages/dotnet.scm
+++ b/gnu/packages/dotnet.scm
@@ -1398,3 +1398,76 @@ (define-public mono-5.8.0
" "
top "/mcs/class/lib/build/mcs.exe")
make-flags)))))))))))
+
+(define mono-pre-5.10.0-external-repo-specs
+ '(("api-doc-tools" "d03e819838c6241f92f90655cb448cc47c9e8791"
+ "1riki79f3ig3cxigviss81dz601hn92a1gifglm0mzjbs76sf3fj"
+ #:recursive? #t)
+ ("api-snapshot" "627333cae84f02a36ee9ca605c96dac4557d9f35"
+ "0p9c6brxiwx38yvaf55jd0l1mxfj3b5ah0xas2hv6frkz80yrqdl")
+ ("aspnetwebstack" "e77b12e6cc5ed260a98447f609e887337e44e299"
+ "0rks344qr4fmp3fs1264d2qkmm348m8d1kjd7z4l94iiirwn1fq1")
+ (("reference-assemblies" "binary-reference-assemblies")
+ "9c5cc7f051a0bba2e41341a5baebfc4d2c2133ef"
+ "14bfn1qvni8gyfxjwmvykyjjy3j5ng4fnbljdadi9dm4b9al0wg1")
+ ("bockbuild" "29022af5d8a94651b2eece93f910559b254ec3f0"
+ "0lclc1smmrj6xw32dll073mxw4ddiixv9arv02yw3w5h135ay7w4")
+ ("boringssl" "3e0770e18835714708860ba9fe1af04a932971ff"
+ "139a0gl91a52k2r6na6ialzkqykaj1rk88zjrkaz3sdxx7nmmg6y")
+ ("cecil" "bc11f472954694ebd92ae4956f110c1036a7c2e0"
+ "122nnp5pcnw18pj6amnqkqxlrmapd4vy9xs65hd0bqyqjh56bwnd")
+ (("cecil" "cecil-legacy") "33d50b874fd527118bc361d83de3d494e8bb55e1"
+ "1p4hl1796ib26ykyf5snl6cj0lx0v7mjh0xqhjw6qdh753nsjyhb")
+ ("corefx" "cb1b049c95227465c1791b857cb5ba86385d9f29"
+ "1pr0qjlgxf63zs1g80gqd6x3qhlgb0wlcc8zm8z8am5aywrvgb53")
+ ("corert" "48dba73801e804e89f00311da99d873f9c550278"
+ "1zw47jf4cwqmaixylisxi73xf6cap41bwf9vlmpxanzxaqklzsvk")
+ ("ikdasm" "465c0815558fd43c0110f8d00fc186ac0044ac6a"
+ "0xir7pcgq04hb7s8g9wsqdrypb6l29raj3iz5rcqzdm0056k75w2")
+ (("ikvm-fork" "ikvm") "847e05fced5c9a41ff0f24f1f9d40d5a8a5772c1"
+ "1fl9bm3lmzf8iqv3x4iqkz9fc54mwdvrxisxg2nvwwcsi4saffpi")
+ ("linker" "99354bf5c13b8055209cb082cddc50c8047ab088"
+ "05zlajnqf83xfvn2whh9nql6j85sq12aw26sqmyqz7zcpml171mj")
+ ("Newtonsoft.Json" "471c3e0803a9f40a0acc8aeceb31de6ff93a52c4"
+ "0dgngd5hqk6yhlg40kabn6qdnknm32zcx9q6bm2w31csnsk5978s")
+ (("NuGet.BuildTasks" "nuget-buildtasks")
+ "b58ba4282377bcefd48abdc2d62ce6330e079abe"
+ "1say03fnqkjsx97zacany3sa5j4mhfk827hkwp23ib02q18f7lvp")
+ (("NUnitLite" "nunit-lite") "764656cdafdb3acd25df8cb52a4e0ea14760fccd"
+ "0pc7lk3p916is8cn4ngaqvjlmlzv3vvjpyksy4pvb3qb5iiaw0vq")
+ ;; ("roslyn-binaries" "1904c7d0682a878e2d25b4d49f3475d12fbb9cc6"
+ ;; "")
+ ("rx" "b29a4b0fda609e0af33ff54ed13652b6ccf0e05e"
+ "1n1jwhmsbkcv2d806immcpzkb72rz04xy98myw355a8w5ah25yiv")
+ ;; ("xunit-binaries" "d4433b0972f40cb3efaa3fbba52869bde5df8fa8"
+ ;; "")
+ ))
+
+(define-public mono-pre-5.10.0
+ (let ((commit "3e9d7d6e9cf8dc33eb29c497c350a1cd7df3a057")
+ (version "5.8.0.129")
+ (revision "0"))
+ (package
+ (inherit mono-5.8.0)
+ (version (git-version version revision commit))
+ (name "mono")
+ (source (origin
+ (method git-fetch)
+ (uri
+ (git-reference
+ (url "https://gitlab.winehq.org/mono/mono.git")
+ (commit commit)))
+ (file-name (git-file-name name version))
+ (sha256
+ (base32
+ "0m8i0zgzh0fgb3ssy95v9czk1c0rl76q0jj7834s5fjnkdj8l4jb"))
+ (modules '((guix build utils)
+ (ice-9 string-fun)))
+ (snippet #~(begin
+ #$(add-external-repos
+ mono-pre-5.10.0-external-repo-specs)
+ #$@prepare-mono-source-0))
+ (patches
+ (search-patches "mono-mcs-patches-from-5.10.0.patch"))))
+ (native-inputs (modify-inputs (package-native-inputs mono-5.8.0)
+ (replace "mono" mono-5.8.0))))))
diff --git a/gnu/packages/patches/mono-mcs-patches-from-5.10.0.patch b/gnu/packages/patches/mono-mcs-patches-from-5.10.0.patch
new file mode 100644
index 00000000000..41dfed7df7f
--- /dev/null
+++ b/gnu/packages/patches/mono-mcs-patches-from-5.10.0.patch
@@ -0,0 +1,4218 @@
+Includes the following commits:
+6f5bfe5cf5a
+3812d1c13fc
+a80f3d0d87c
+b2f051f0b19
+2a202a8478b
+4d7d1606d73
+d9970305731
+94e80fc8d7f
+0b9280083a9
+07d1e5f36a5
+5f279f14aa2
+889421f3bef
+f4c0fd3dc11
+71df5c63b46
+d6e5bf16782
+207f5c2cd6d
+c512752a416
+9aca8d5fe4b
+diff --git a/mcs/class/Mono.CSharp/Test/Evaluator/TypesTest.cs b/mcs/class/Mono.CSharp/Test/Evaluator/TypesTest.cs
+index 97f9e047e6d..f8bf63455de 100644
+--- a/mcs/class/Mono.CSharp/Test/Evaluator/TypesTest.cs
++++ b/mcs/class/Mono.CSharp/Test/Evaluator/TypesTest.cs
+@@ -131,5 +131,17 @@ namespace MonoTests.EvaluatorTest
+ {
+ Evaluator.Run ("public class TestClass { private TestEnum _te; public string Get() { return _te.ToString(); } } public enum TestEnum { First, Second }");
+ }
++
++ [Test]
++ public void EnumTypeWithOrderDependency ()
++ {
++ Evaluator.Run ("public class TestClass { public enum TestEnum { Val1, Val2, Val3 } public TestEnum test; public TestClass() { test = TestEnum.Val3; } }");
++ object res = Evaluator.Evaluate ("new TestClass()");
++
++ var fields = res.GetType ().GetFields ();
++ foreach (var field in fields) {
++ Console.WriteLine ($"{field.Name} = {field.MemberType}");
++ }
++ }
+ }
+ }
+\ No newline at end of file
+diff --git a/mcs/errors/cs0023-30.cs b/mcs/errors/cs0023-30.cs
+new file mode 100644
+index 00000000000..fc19cc24e3e
+--- /dev/null
++++ b/mcs/errors/cs0023-30.cs
+@@ -0,0 +1,11 @@
++// CS0023: The `is' operator cannot be applied to operand of type `default'
++// Line: 9
++// Compiler options: -langversion:latest
++
++class C
++{
++ static void Main ()
++ {
++ bool d = default is C;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0029-39.cs b/mcs/errors/cs0029-39.cs
+new file mode 100644
+index 00000000000..0ed200036dc
+--- /dev/null
++++ b/mcs/errors/cs0029-39.cs
+@@ -0,0 +1,15 @@
++// CS0029: Cannot implicitly convert type `S' to `object'
++// Line: 13
++// Compiler options: -langversion:latest
++
++public ref struct S
++{
++}
++
++class Test
++{
++ public static void Main ()
++ {
++ object o = new S ();
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0029-40.cs b/mcs/errors/cs0029-40.cs
+new file mode 100644
+index 00000000000..6d9167c31fa
+--- /dev/null
++++ b/mcs/errors/cs0029-40.cs
+@@ -0,0 +1,19 @@
++// CS0029: Cannot implicitly convert type `S' to `System.ValueType'
++// Line: 16
++// Compiler options: -langversion:latest
++
++using System;
++
++public ref struct S
++{
++}
++
++class Test
++{
++ public static void Main ()
++ {
++ var s = default (S);
++ ValueType s2 = s;
++ var res = default (S).ToString ();
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0029-41.cs b/mcs/errors/cs0029-41.cs
+new file mode 100644
+index 00000000000..1a65f52f737
+--- /dev/null
++++ b/mcs/errors/cs0029-41.cs
+@@ -0,0 +1,12 @@
++// CS0029: Cannot implicitly convert type `System.TypedReference' to `object'
++// Line: 10
++
++using System;
++
++class Test
++{
++ public static void Main ()
++ {
++ var res = default (TypedReference).ToString ();
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0029-42.cs b/mcs/errors/cs0029-42.cs
+new file mode 100644
+index 00000000000..c7671000c76
+--- /dev/null
++++ b/mcs/errors/cs0029-42.cs
+@@ -0,0 +1,10 @@
++// CS0029: Cannot implicitly convert type `string' to `int'
++// Line: 8
++
++class C
++{
++ void Exists (int _)
++ {
++ _ = "2";
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0030-17.cs b/mcs/errors/cs0030-17.cs
+new file mode 100644
+index 00000000000..b72b8bf71e5
+--- /dev/null
++++ b/mcs/errors/cs0030-17.cs
+@@ -0,0 +1,15 @@
++// CS0030: Cannot convert type `object' to `S'
++// Line: 13
++// Compiler options: -langversion:latest
++
++ref struct S
++{
++}
++
++class X
++{
++ public static void Foo (object o)
++ {
++ var res = (S) o;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0103-18.cs b/mcs/errors/cs0103-18.cs
+new file mode 100644
+index 00000000000..8cec755d23d
+--- /dev/null
++++ b/mcs/errors/cs0103-18.cs
+@@ -0,0 +1,10 @@
++// CS0103: The name `_' does not exist in the current context
++// Line: 8
++
++class C
++{
++ void Test ()
++ {
++ _.ToString ();
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0123-10.cs b/mcs/errors/cs0123-10.cs
+new file mode 100644
+index 00000000000..43d5e5d6368
+--- /dev/null
++++ b/mcs/errors/cs0123-10.cs
+@@ -0,0 +1,18 @@
++// CS0123: A method or delegate `object.ToString()' parameters do not match delegate `System.Func<string>()' parameters
++// Line: 16
++// Compiler options: -langversion:latest
++
++using System;
++
++public ref struct S
++{
++}
++
++class Test
++{
++ public static void Main ()
++ {
++ var s = new S ();
++ Func<string> f = s.ToString;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0123-11.cs b/mcs/errors/cs0123-11.cs
+new file mode 100644
+index 00000000000..427b628c159
+--- /dev/null
++++ b/mcs/errors/cs0123-11.cs
+@@ -0,0 +1,12 @@
++// CS0123: A method or delegate `object.ToString()' parameters do not match delegate `System.Func<string>()' parameters
++// Line: 16
++
++using System;
++
++class Test
++{
++ public static void Main ()
++ {
++ Func<string> f = default (TypedReference).ToString;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0133-2.cs b/mcs/errors/cs0133-2.cs
+index b7a37182d73..48488876f7e 100644
+--- a/mcs/errors/cs0133-2.cs
++++ b/mcs/errors/cs0133-2.cs
+@@ -1,4 +1,4 @@
+-// CS0133: The expression being assigned to `c' must be constant
++// CS0133: The expression being assigned to `c' must be a constant or default value
+ // Line: 10
+
+ class C
+diff --git a/mcs/errors/cs0133-3.cs b/mcs/errors/cs0133-3.cs
+index caae3bde68c..2f7dac6880d 100644
+--- a/mcs/errors/cs0133-3.cs
++++ b/mcs/errors/cs0133-3.cs
+@@ -1,5 +1,5 @@
+-// CS0133: The expression being assigned to `Foo' must be constant
+-// Line: 12
++// CS0133: The expression being assigned to `Foo' must be a constant or default value
++// Line: 8
+
+ class T
+ {
+diff --git a/mcs/errors/cs0133-4.cs b/mcs/errors/cs0133-4.cs
+index 41fe639b446..54162d544ca 100644
+--- a/mcs/errors/cs0133-4.cs
++++ b/mcs/errors/cs0133-4.cs
+@@ -1,4 +1,4 @@
+-// CS0133: The expression being assigned to `S.pathName' must be constant
++// CS0133: The expression being assigned to `S.pathName' must be a constant or default value
+ // Line: 12
+ // Compiler options: -unsafe
+
+diff --git a/mcs/errors/cs0133-5.cs b/mcs/errors/cs0133-5.cs
+index a49f265c690..32e6bfdf416 100644
+--- a/mcs/errors/cs0133-5.cs
++++ b/mcs/errors/cs0133-5.cs
+@@ -1,4 +1,4 @@
+-// CS0133: The expression being assigned to `b' must be constant
++// CS0133: The expression being assigned to `b' must be a constant or default value
+ // Line: 8
+
+ class X
+diff --git a/mcs/errors/cs0133-6.cs b/mcs/errors/cs0133-6.cs
+index a523169cdbd..28448dd6de8 100644
+--- a/mcs/errors/cs0133-6.cs
++++ b/mcs/errors/cs0133-6.cs
+@@ -1,4 +1,4 @@
+-// CS0133: The expression being assigned to `o' must be constant
++// CS0133: The expression being assigned to `o' must be a constant or default value
+ // Line: 8
+
+ class X
+diff --git a/mcs/errors/cs0133-7.cs b/mcs/errors/cs0133-7.cs
+index 10d82d9fe5e..024bc148229 100644
+--- a/mcs/errors/cs0133-7.cs
++++ b/mcs/errors/cs0133-7.cs
+@@ -1,4 +1,4 @@
+-// CS0133: The expression being assigned to `o' must be constant
++// CS0133: The expression being assigned to `o' must be a constant or default value
+ // Line: 8
+
+ class X
+diff --git a/mcs/errors/cs0133.cs b/mcs/errors/cs0133.cs
+index 094194deabb..f0dda9ee3cb 100644
+--- a/mcs/errors/cs0133.cs
++++ b/mcs/errors/cs0133.cs
+@@ -1,5 +1,6 @@
+-// CS0133: The expression being assigned to `x' must be constant
+-// Line: 6
++// CS0133: The expression being assigned to `x' must be a constant or default value
++// Line: 7
++
+ class X {
+ X (int arg)
+ {
+diff --git a/mcs/errors/cs0306-4.cs b/mcs/errors/cs0306-4.cs
+new file mode 100644
+index 00000000000..4653512e55b
+--- /dev/null
++++ b/mcs/errors/cs0306-4.cs
+@@ -0,0 +1,15 @@
++// CS0306: The type `S' may not be used as a type argument
++// Line: 13
++// Compiler options: -langversion:latest
++
++public ref struct S
++{
++}
++
++class Test<T>
++{
++ public static void Foo ()
++ {
++ Test<S> local;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0611-3.cs b/mcs/errors/cs0611-3.cs
+new file mode 100644
+index 00000000000..6eda773dd24
+--- /dev/null
++++ b/mcs/errors/cs0611-3.cs
+@@ -0,0 +1,15 @@
++// CS0611: Array elements cannot be of type `S'
++// Line: 13
++// Compiler options: -langversion:latest
++
++public ref struct S
++{
++}
++
++class Test
++{
++ public static void Main ()
++ {
++ var x = new S[0];
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs0815-9.cs b/mcs/errors/cs0815-9.cs
+new file mode 100644
+index 00000000000..f54703349be
+--- /dev/null
++++ b/mcs/errors/cs0815-9.cs
+@@ -0,0 +1,11 @@
++// CS0815: An implicitly typed local variable declaration cannot be initialized with `default'
++// Line: 9
++// Compiler options: -langversion:latest
++
++static class X
++{
++ public static void Main ()
++ {
++ var x = default;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs1502-11.cs b/mcs/errors/cs1502-11.cs
+deleted file mode 100644
+index 82dcb3a2c17..00000000000
+--- a/mcs/errors/cs1502-11.cs
++++ /dev/null
+@@ -1,11 +0,0 @@
+-// CS1502: The best overloaded method match for `string.String(char*)' has some invalid arguments
+-// Line: 8
+-
+-class C
+-{
+- static string Prop {
+- get {
+- return new string ("s");
+- }
+- }
+-}
+diff --git a/mcs/errors/cs1599-2.cs b/mcs/errors/cs1599-2.cs
+index 941ff6bb0d6..28aa05b2ed3 100644
+--- a/mcs/errors/cs1599-2.cs
++++ b/mcs/errors/cs1599-2.cs
+@@ -1,4 +1,4 @@
+-// CS1599: Method or delegate cannot return type `System.ArgIterator'
++// CS1599: The return type of `System.ArgIterator' is not allowed
+ // Line: 8
+
+ using System;
+diff --git a/mcs/errors/cs1599-3.cs b/mcs/errors/cs1599-3.cs
+index e4869dcaf70..9d378099d82 100644
+--- a/mcs/errors/cs1599-3.cs
++++ b/mcs/errors/cs1599-3.cs
+@@ -1,4 +1,4 @@
+-// CS1599: Method or delegate cannot return type `System.ArgIterator'
++// CS1599: The return type of `System.ArgIterator' is not allowed
+ // Line: 8
+
+ using System;
+diff --git a/mcs/errors/cs1599-4.cs b/mcs/errors/cs1599-4.cs
+new file mode 100644
+index 00000000000..358eee59a13
+--- /dev/null
++++ b/mcs/errors/cs1599-4.cs
+@@ -0,0 +1,12 @@
++// CS1599: The return type of `System.TypedReference' is not allowed
++// Line: 8
++
++using System;
++
++public class Program
++{
++ public static TypedReference operator + (int a, Program b)
++ {
++ throw new ApplicationException ();
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs1599.cs b/mcs/errors/cs1599.cs
+index 5cef32d7f97..871d9fb3e7a 100644
+--- a/mcs/errors/cs1599.cs
++++ b/mcs/errors/cs1599.cs
+@@ -1,4 +1,4 @@
+-// CS1599: Method or delegate cannot return type `System.TypedReference'
++// CS1599: The return type of `System.TypedReference' is not allowed
+ // Line: 8
+
+ using System;
+diff --git a/mcs/errors/cs1644-57.cs b/mcs/errors/cs1644-57.cs
+new file mode 100644
+index 00000000000..7ee98373080
+--- /dev/null
++++ b/mcs/errors/cs1644-57.cs
+@@ -0,0 +1,7 @@
++// CS1644: Feature `ref structs' cannot be used because it is not part of the C# 7.0 language specification
++// Line: 5
++// Compiler options: -langversion:7
++
++ref struct S
++{
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs1644-58.cs b/mcs/errors/cs1644-58.cs
+new file mode 100644
+index 00000000000..e994cf338bd
+--- /dev/null
++++ b/mcs/errors/cs1644-58.cs
+@@ -0,0 +1,8 @@
++// CS1644: Feature `default literal' cannot be used because it is not part of the C# 7.0 language specification
++// Line: 7
++// Compiler options: -langversion:7
++
++class X
++{
++ int i = default;
++}
+diff --git a/mcs/errors/cs1644-59.cs b/mcs/errors/cs1644-59.cs
+new file mode 100644
+index 00000000000..2f8aed6b958
+--- /dev/null
++++ b/mcs/errors/cs1644-59.cs
+@@ -0,0 +1,13 @@
++// CS1644: Feature `readonly references' cannot be used because it is not part of the C# 7.0 language specification
++// Line: 9
++// Compiler options: -langversion:7
++
++class X
++{
++ int i;
++
++ ref readonly int Test ()
++ {
++ return ref i;
++ }
++}
+diff --git a/mcs/errors/cs1644-60.cs b/mcs/errors/cs1644-60.cs
+new file mode 100644
+index 00000000000..ca9547bc561
+--- /dev/null
++++ b/mcs/errors/cs1644-60.cs
+@@ -0,0 +1,11 @@
++// CS1644: Feature `discards' cannot be used because it is not part of the C# 6.0 language specification
++// Line: 9
++// Compiler options: -langversion:6
++
++class X
++{
++ int Test ()
++ {
++ _ = 2;
++ }
++}
+diff --git a/mcs/errors/cs1738-2.cs b/mcs/errors/cs1738-2.cs
+index f59221f4c7a..44b3f6d1b14 100644
+--- a/mcs/errors/cs1738-2.cs
++++ b/mcs/errors/cs1738-2.cs
+@@ -1,4 +1,4 @@
+-// CS1738: Named arguments must appear after the positional arguments
++// CS1738: Named arguments must appear after the positional arguments when using language version older than 7.2
+ // Line: 13
+
+ using System;
+diff --git a/mcs/errors/cs1738-3.cs b/mcs/errors/cs1738-3.cs
+index 53c4efc3553..901ac0e5d59 100644
+--- a/mcs/errors/cs1738-3.cs
++++ b/mcs/errors/cs1738-3.cs
+@@ -1,4 +1,4 @@
+-// CS1738: Named arguments must appear after the positional arguments
++// CS1738: Named arguments must appear after the positional arguments when using language version older than 7.2
+ // Line: 14
+
+ class C
+diff --git a/mcs/errors/cs1738.cs b/mcs/errors/cs1738.cs
+index dab9a61160b..537bc17b917 100644
+--- a/mcs/errors/cs1738.cs
++++ b/mcs/errors/cs1738.cs
+@@ -1,4 +1,4 @@
+-// CS1738: Named arguments must appear after the positional arguments
++// CS1738: Named arguments must appear after the positional arguments when using language version older than 7.2
+ // Line: 12
+
+ class C
+diff --git a/mcs/errors/cs1983.cs b/mcs/errors/cs1983.cs
+index a2ef6c150d6..76d2db4e677 100644
+--- a/mcs/errors/cs1983.cs
++++ b/mcs/errors/cs1983.cs
+@@ -1,4 +1,4 @@
+-// CS1983: The return type of an async method must be void, Task, or Task<T>
++// CS1983: The return type of an async method must be void or task type
+ // Line: 6
+
+ class C
+diff --git a/mcs/errors/cs4012-3.cs b/mcs/errors/cs4012-3.cs
+new file mode 100644
+index 00000000000..fb3d1dc276f
+--- /dev/null
++++ b/mcs/errors/cs4012-3.cs
+@@ -0,0 +1,19 @@
++// CS4012: Parameters or local variables of type `S' cannot be declared in async methods or iterators
++// Line: 16
++// Compiler options: -langversion:latest
++
++using System;
++using System.Threading.Tasks;
++
++public ref struct S
++{
++}
++
++class C
++{
++ public async void Test ()
++ {
++ var tr = new S ();
++ await Task.Factory.StartNew (() => 6);
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8175-2.cs b/mcs/errors/cs8175-2.cs
+new file mode 100644
+index 00000000000..27c4babf8bf
+--- /dev/null
++++ b/mcs/errors/cs8175-2.cs
+@@ -0,0 +1,19 @@
++// CS8175: Cannot use by-reference variable `s' inside an anonymous method, lambda expression, or query expression
++// Line: 17
++// Compiler options: -langversion:latest
++
++using System;
++
++public ref struct S
++{
++}
++
++class Test
++{
++ public static void Main ()
++ {
++ var s = new S ();
++
++ Action a = () => Console.WriteLine (s);
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8183.cs b/mcs/errors/cs8183.cs
+new file mode 100644
+index 00000000000..f9e9004b737
+--- /dev/null
++++ b/mcs/errors/cs8183.cs
+@@ -0,0 +1,11 @@
++// CS8183: Cannot infer the type of implicitly-typed discard
++// Line: 9
++// Compiler options: -langversion:7.2
++
++class X
++{
++ public static void Main ()
++ {
++ _ = default;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8184.cs b/mcs/errors/cs8184.cs
+new file mode 100644
+index 00000000000..19a4685d7bd
+--- /dev/null
++++ b/mcs/errors/cs8184.cs
+@@ -0,0 +1,10 @@
++// CS8184: A deconstruction cannot mix declarations and expressions on the left-hand-side
++// Line: 8
++
++class X
++{
++ public static void Main ()
++ {
++ (int a, b) = (1, 2);
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8207.cs b/mcs/errors/cs8207.cs
+new file mode 100644
+index 00000000000..31090948b45
+--- /dev/null
++++ b/mcs/errors/cs8207.cs
+@@ -0,0 +1,19 @@
++// CS8207: An expression tree cannot contain a discard
++// Line: 11
++
++using System;
++using System.Linq.Expressions;
++
++class X
++{
++ void Test ()
++ {
++ Expression<Func<bool>> e = () => TryGetValue (out _);
++ }
++
++ bool TryGetValue (out int arg)
++ {
++ arg = 3;
++ return true;
++ }
++}
+diff --git a/mcs/errors/cs8209.cs b/mcs/errors/cs8209.cs
+new file mode 100644
+index 00000000000..3a46a206c8e
+--- /dev/null
++++ b/mcs/errors/cs8209.cs
+@@ -0,0 +1,10 @@
++// CS8209: Cannot assign void to a discard
++// Line: 8
++
++class C
++{
++ public static void Main ()
++ {
++ _ = Main ();
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8310.cs b/mcs/errors/cs8310.cs
+new file mode 100644
+index 00000000000..134624c03b7
+--- /dev/null
++++ b/mcs/errors/cs8310.cs
+@@ -0,0 +1,11 @@
++// CS8310: Operator `+' cannot be applied to operand `default'
++// Line: 9
++// Compiler options: -langversion:latest
++
++class C
++{
++ static void Main ()
++ {
++ int h = 1 + default;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8311.cs b/mcs/errors/cs8311.cs
+new file mode 100644
+index 00000000000..5b35229442d
+--- /dev/null
++++ b/mcs/errors/cs8311.cs
+@@ -0,0 +1,12 @@
++// CS8311: Cannot use a default literal as an argument to a dynamically dispatched operation
++// Line: 10
++// Compiler options: -langversion:latest
++
++class C
++{
++ static void Main ()
++ {
++ dynamic d = null;
++ d.M2 (default);
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8312.cs b/mcs/errors/cs8312.cs
+new file mode 100644
+index 00000000000..d2ad3f52f02
+--- /dev/null
++++ b/mcs/errors/cs8312.cs
+@@ -0,0 +1,12 @@
++// CS8312: Use of default literal is not valid in this context
++// Line: 9
++// Compiler options: -langversion:latest
++
++class C
++{
++ static void Main ()
++ {
++ foreach (var x in default) {
++ }
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8315.cs b/mcs/errors/cs8315.cs
+new file mode 100644
+index 00000000000..c40bf8613b4
+--- /dev/null
++++ b/mcs/errors/cs8315.cs
+@@ -0,0 +1,11 @@
++// CS8315: Operator `==' is ambiguous on operands `default' and `default'
++// Line: 9
++// Compiler options: -langversion:latest
++
++class C
++{
++ static void Main ()
++ {
++ bool d = default == default;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8323.cs b/mcs/errors/cs8323.cs
+new file mode 100644
+index 00000000000..c6c9309ec0d
+--- /dev/null
++++ b/mcs/errors/cs8323.cs
+@@ -0,0 +1,15 @@
++// CS8323: Named argument `str' is used out of position but is followed by positional argument
++// Line: 9
++// Compiler options: -langversion:7.2
++
++class X
++{
++ public static void Main ()
++ {
++ Test (str: "", "");
++ }
++
++ static void Test (int arg, string str)
++ {
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8324.cs b/mcs/errors/cs8324.cs
+new file mode 100644
+index 00000000000..8a0be1aefb9
+--- /dev/null
++++ b/mcs/errors/cs8324.cs
+@@ -0,0 +1,12 @@
++// CS8324: Named argument specifications must appear after all fixed arguments have been specified in a dynamic invocation
++// Line: 10
++// Compiler options: -langversion:7.2
++
++class C
++{
++ void M ()
++ {
++ dynamic d = new object ();
++ d.M (arg: 1, "");
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8343.cs b/mcs/errors/cs8343.cs
+new file mode 100644
+index 00000000000..b6aa8e83a09
+--- /dev/null
++++ b/mcs/errors/cs8343.cs
+@@ -0,0 +1,12 @@
++// CS8343: `S': ref structs cannot implement interfaces
++// Line: 7
++// Compiler options: -langversion:latest
++
++using System;
++
++public ref struct S : IDisposable
++{
++ public void Dispose ()
++ {
++ }
++}
+diff --git a/mcs/errors/cs8345-2.cs b/mcs/errors/cs8345-2.cs
+new file mode 100644
+index 00000000000..3f6137b1b56
+--- /dev/null
++++ b/mcs/errors/cs8345-2.cs
+@@ -0,0 +1,12 @@
++// CS8345: Field or auto-implemented property cannot be of type `S' unless it is an instance member of a ref struct
++// Line: 11
++// Compiler options: -langversion:latest
++
++public ref struct S
++{
++}
++
++ref struct Test
++{
++ static S field;
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8345.cs b/mcs/errors/cs8345.cs
+new file mode 100644
+index 00000000000..0b5bd05518f
+--- /dev/null
++++ b/mcs/errors/cs8345.cs
+@@ -0,0 +1,12 @@
++// CS8345: Field or auto-implemented property cannot be of type `S' unless it is an instance member of a ref struct
++// Line: 11
++// Compiler options: -langversion:latest
++
++public ref struct S
++{
++}
++
++struct Test
++{
++ S field;
++}
+\ No newline at end of file
+diff --git a/mcs/errors/cs8346.cs b/mcs/errors/cs8346.cs
+new file mode 100644
+index 00000000000..58e22a2ae7f
+--- /dev/null
++++ b/mcs/errors/cs8346.cs
+@@ -0,0 +1,13 @@
++// CS8346: Cannot convert a stackalloc expression of type `byte' to type `System.Span<int>'
++// Line: 11
++// Compiler options: -langversion:7.2
++
++using System;
++
++class X
++{
++ public static void Main ()
++ {
++ Span<int> stackSpan = stackalloc byte[1];
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/mcs/argument.cs b/mcs/mcs/argument.cs
+index 8421b4dfbfc..5b1003dbadf 100644
+--- a/mcs/mcs/argument.cs
++++ b/mcs/mcs/argument.cs
+@@ -106,11 +106,6 @@ namespace Mono.CSharp
+
+ public virtual Expression CreateExpressionTree (ResolveContext rc)
+ {
+- if (Type.Kind == MemberKind.ByRef) {
+- rc.Report.Error (8153, Expr.Location, "An expression tree lambda cannot contain a call to a method, property, or indexer that returns by reference");
+- return null;
+- }
+-
+ if (ArgType == AType.Default)
+ rc.Report.Error (854, Expr.Location, "An expression tree cannot contain an invocation which uses optional parameter");
+
+diff --git a/mcs/mcs/assign.cs b/mcs/mcs/assign.cs
+index a07c8c0ef39..596623feae4 100644
+--- a/mcs/mcs/assign.cs
++++ b/mcs/mcs/assign.cs
+@@ -391,9 +391,21 @@ namespace Mono.CSharp {
+ return System.Linq.Expressions.Expression.Assign (target_object, source_object);
+ }
+
+- protected virtual Expression ResolveConversions (ResolveContext ec)
++ protected virtual Expression ResolveConversions (ResolveContext rc)
+ {
+- source = Convert.ImplicitConversionRequired (ec, source, target.Type, source.Location);
++ var ttype = target.Type;
++ var stackAlloc = source as StackAlloc;
++ if (stackAlloc != null && ttype.Arity == 1 && ttype.GetDefinition () == rc.Module.PredefinedTypes.SpanGeneric.TypeSpec &&
++ rc.Module.Compiler.Settings.Version >= LanguageVersion.V_7_2) {
++
++ var etype = ttype.TypeArguments [0];
++ var stype = ((PointerContainer)source.Type).Element;
++ if (etype == stype && stackAlloc.ResolveSpanConversion (rc, ttype)) {
++ return this;
++ }
++ }
++
++ source = Convert.ImplicitConversionRequired (rc, source, ttype, source.Location);
+ if (source == null)
+ return null;
+
+diff --git a/mcs/mcs/async.cs b/mcs/mcs/async.cs
+index fd6499346e8..643aed5e568 100644
+--- a/mcs/mcs/async.cs
++++ b/mcs/mcs/async.cs
+@@ -628,58 +628,112 @@ namespace Mono.CSharp
+
+ protected override bool DoDefineMembers ()
+ {
+- PredefinedType builder_type;
+- PredefinedMember<MethodSpec> bf;
+- PredefinedMember<MethodSpec> bs;
+- PredefinedMember<MethodSpec> sr;
+- PredefinedMember<MethodSpec> se;
+- PredefinedMember<MethodSpec> sm;
++ TypeSpec bt;
+ bool has_task_return_type = false;
+- var pred_members = Module.PredefinedMembers;
++ var istate_machine = Module.PredefinedTypes.IAsyncStateMachine;
++ MethodSpec set_statemachine;
+
+- if (return_type.Kind == MemberKind.Void) {
+- builder_type = Module.PredefinedTypes.AsyncVoidMethodBuilder;
+- bf = pred_members.AsyncVoidMethodBuilderCreate;
+- bs = pred_members.AsyncVoidMethodBuilderStart;
+- sr = pred_members.AsyncVoidMethodBuilderSetResult;
+- se = pred_members.AsyncVoidMethodBuilderSetException;
+- sm = pred_members.AsyncVoidMethodBuilderSetStateMachine;
+- } else if (return_type == Module.PredefinedTypes.Task.TypeSpec) {
+- builder_type = Module.PredefinedTypes.AsyncTaskMethodBuilder;
+- bf = pred_members.AsyncTaskMethodBuilderCreate;
+- bs = pred_members.AsyncTaskMethodBuilderStart;
+- sr = pred_members.AsyncTaskMethodBuilderSetResult;
+- se = pred_members.AsyncTaskMethodBuilderSetException;
+- sm = pred_members.AsyncTaskMethodBuilderSetStateMachine;
+- task = pred_members.AsyncTaskMethodBuilderTask.Get ();
++ if (return_type.IsCustomTaskType ()) {
++ //
++ // TODO: Would be nice to cache all this on per-type basis
++ //
++ var btypes = Compiler.BuiltinTypes;
++ bt = return_type.MemberDefinition.GetAsyncMethodBuilder ();
++ TypeSpec bt_inflated;
++ if (return_type.IsGeneric) {
++ bt_inflated = bt.MakeGenericType (Module, bt.MemberDefinition.TypeParameters);
++ } else {
++ bt_inflated = bt;
++ }
++
++ var set_result_sign = MemberFilter.Method ("SetResult", 0, ParametersCompiled.CreateFullyResolved (bt.MemberDefinition.TypeParameters), btypes.Void);
++ set_result = new PredefinedMember<MethodSpec> (Module, bt, set_result_sign).Resolve (Location);
++
++ var set_exception_sign = MemberFilter.Method ("SetException", 0, ParametersCompiled.CreateFullyResolved (btypes.Exception), btypes.Void);
++ set_exception = new PredefinedMember<MethodSpec> (Module, bt, set_exception_sign).Resolve (Location);
++
++ var builder_factory_sign = MemberFilter.Method ("Create", 0, ParametersCompiled.EmptyReadOnlyParameters, bt_inflated);
++ builder_factory = new PredefinedMember<MethodSpec> (Module, bt, builder_factory_sign).Resolve (Location);
++ if (builder_factory?.IsStatic == false)
++ throw new NotImplementedException ("report better error message");
++
++ var builder_start_sign = MemberFilter.Method ("Start", 1, new ParametersImported (
++ new [] {
++ new ParameterData (null, Parameter.Modifier.REF),
++ },
++ new [] {
++ new TypeParameterSpec (0, null, SpecialConstraint.None, Variance.None, null),
++ }, false),
++ btypes.Void);
++ builder_start = new PredefinedMember<MethodSpec> (Module, bt, builder_start_sign).Resolve (Location);
++
++ if (!istate_machine.Define ())
++ return false;
++
++ var set_statemachine_sign = MemberFilter.Method ("SetStateMachine", 0, ParametersCompiled.CreateFullyResolved (istate_machine.TypeSpec), btypes.Void);
++ set_statemachine = new PredefinedMember<MethodSpec> (Module, bt, set_statemachine_sign).Resolve (Location); ;
++
++ var task_sign = MemberFilter.Property ("Task", return_type.MemberDefinition as TypeSpec);
++ task = new PredefinedMember<PropertySpec> (Module, bt, task_sign).Resolve (Location);
++
++ if (set_result == null || set_exception == null || builder_factory == null || builder_start == null || set_statemachine == null || task == null ||
++ !Module.PredefinedTypes.INotifyCompletion.Define ()) {
++ return false;
++ }
++
++ has_task_return_type = return_type.IsGeneric;
+ } else {
+- builder_type = Module.PredefinedTypes.AsyncTaskMethodBuilderGeneric;
+- bf = pred_members.AsyncTaskMethodBuilderGenericCreate;
+- bs = pred_members.AsyncTaskMethodBuilderGenericStart;
+- sr = pred_members.AsyncTaskMethodBuilderGenericSetResult;
+- se = pred_members.AsyncTaskMethodBuilderGenericSetException;
+- sm = pred_members.AsyncTaskMethodBuilderGenericSetStateMachine;
+- task = pred_members.AsyncTaskMethodBuilderGenericTask.Get ();
+- has_task_return_type = true;
+- }
++ PredefinedType builder_type;
++ PredefinedMember<MethodSpec> bf;
++ PredefinedMember<MethodSpec> bs;
++ PredefinedMember<MethodSpec> sr;
++ PredefinedMember<MethodSpec> se;
++ PredefinedMember<MethodSpec> sm;
++ var pred_members = Module.PredefinedMembers;
++
++ if (return_type.Kind == MemberKind.Void) {
++ builder_type = Module.PredefinedTypes.AsyncVoidMethodBuilder;
++ bf = pred_members.AsyncVoidMethodBuilderCreate;
++ bs = pred_members.AsyncVoidMethodBuilderStart;
++ sr = pred_members.AsyncVoidMethodBuilderSetResult;
++ se = pred_members.AsyncVoidMethodBuilderSetException;
++ sm = pred_members.AsyncVoidMethodBuilderSetStateMachine;
++ } else if (return_type == Module.PredefinedTypes.Task.TypeSpec) {
++ builder_type = Module.PredefinedTypes.AsyncTaskMethodBuilder;
++ bf = pred_members.AsyncTaskMethodBuilderCreate;
++ bs = pred_members.AsyncTaskMethodBuilderStart;
++ sr = pred_members.AsyncTaskMethodBuilderSetResult;
++ se = pred_members.AsyncTaskMethodBuilderSetException;
++ sm = pred_members.AsyncTaskMethodBuilderSetStateMachine;
++ task = pred_members.AsyncTaskMethodBuilderTask.Get ();
++ } else {
++ builder_type = Module.PredefinedTypes.AsyncTaskMethodBuilderGeneric;
++ bf = pred_members.AsyncTaskMethodBuilderGenericCreate;
++ bs = pred_members.AsyncTaskMethodBuilderGenericStart;
++ sr = pred_members.AsyncTaskMethodBuilderGenericSetResult;
++ se = pred_members.AsyncTaskMethodBuilderGenericSetException;
++ sm = pred_members.AsyncTaskMethodBuilderGenericSetStateMachine;
++ task = pred_members.AsyncTaskMethodBuilderGenericTask.Get ();
++ has_task_return_type = true;
++ }
+
+- set_result = sr.Get ();
+- set_exception = se.Get ();
+- builder_factory = bf.Get ();
+- builder_start = bs.Get ();
++ set_result = sr.Get ();
++ set_exception = se.Get ();
++ builder_factory = bf.Get ();
++ builder_start = bs.Get ();
+
+- var istate_machine = Module.PredefinedTypes.IAsyncStateMachine;
+- var set_statemachine = sm.Get ();
+-
+- if (!builder_type.Define () || !istate_machine.Define () || set_result == null || builder_factory == null ||
+- set_exception == null || set_statemachine == null || builder_start == null ||
+- !Module.PredefinedTypes.INotifyCompletion.Define ()) {
+- Report.Error (1993, Location,
+- "Cannot find compiler required types for asynchronous functions support. Are you targeting the wrong framework version?");
+- return base.DoDefineMembers ();
+- }
++ set_statemachine = sm.Get ();
++
++ if (!builder_type.Define () || !istate_machine.Define () || set_result == null || builder_factory == null ||
++ set_exception == null || set_statemachine == null || builder_start == null ||
++ !Module.PredefinedTypes.INotifyCompletion.Define ()) {
++ Report.Error (1993, Location,
++ "Cannot find compiler required types for asynchronous functions support. Are you targeting the wrong framework version?");
++ return base.DoDefineMembers ();
++ }
+
+- var bt = builder_type.TypeSpec;
++ bt = builder_type.TypeSpec;
++ }
+
+ //
+ // Inflate generic Task types
+@@ -825,9 +879,26 @@ namespace Mono.CSharp
+ predefined = unsafeVersion ? pm.AsyncVoidMethodBuilderOnCompletedUnsafe : pm.AsyncVoidMethodBuilderOnCompleted;
+ } else if (return_type == Module.PredefinedTypes.Task.TypeSpec) {
+ predefined = unsafeVersion ? pm.AsyncTaskMethodBuilderOnCompletedUnsafe : pm.AsyncTaskMethodBuilderOnCompleted;
+- } else {
++ } else if (return_type.IsGenericTask) {
+ predefined = unsafeVersion ? pm.AsyncTaskMethodBuilderGenericOnCompletedUnsafe : pm.AsyncTaskMethodBuilderGenericOnCompleted;
+ has_task_return_type = true;
++ } else {
++ var parameters = new ParametersImported (
++ new [] {
++ new ParameterData (null, Parameter.Modifier.REF),
++ new ParameterData (null, Parameter.Modifier.REF)
++ },
++ new [] {
++ new TypeParameterSpec (0, null, SpecialConstraint.None, Variance.None, null),
++ new TypeParameterSpec (1, null, SpecialConstraint.None, Variance.None, null)
++ }, false);
++
++ var on_completed_sign = unsafeVersion ?
++ MemberFilter.Method ("AwaitUnsafeOnCompleted", 2, parameters, Compiler.BuiltinTypes.Void) :
++ MemberFilter.Method ("AwaitOnCompleted", 2, parameters, Compiler.BuiltinTypes.Void);
++
++ predefined = new PredefinedMember<MethodSpec> (Module, return_type.MemberDefinition.GetAsyncMethodBuilder (), on_completed_sign);
++ has_task_return_type = return_type.IsGeneric;
+ }
+
+ var on_completed = predefined.Resolve (Location);
+@@ -887,11 +958,14 @@ namespace Mono.CSharp
+ // stateMachine.$builder.Start<{storey-type}>(ref stateMachine);
+ //
+ instance.AddressOf (ec, AddressOp.Store);
+- ec.Emit (OpCodes.Ldflda, builder_field);
++
++ bool struct_builder = builder.MemberType.IsStruct;
++
++ ec.Emit (struct_builder ? OpCodes.Ldflda : OpCodes.Ldfld, builder_field);
+ if (Task != null)
+ ec.Emit (OpCodes.Dup);
+ instance.AddressOf (ec, AddressOp.Store);
+- ec.Emit (OpCodes.Call, builder_start.MakeGenericMethod (Module, instance.Type));
++ ec.Emit (struct_builder ? OpCodes.Call : OpCodes.Callvirt, builder_start.MakeGenericMethod (Module, instance.Type));
+
+ //
+ // Emits return stateMachine.$builder.Task;
+@@ -1029,4 +1103,20 @@ namespace Mono.CSharp
+ EmitAssign (ec, new NullConstant (type, loc), false, false);
+ }
+ }
++
++ static class TypeSpecAsyncExtensions
++ {
++ public static bool IsCustomTaskType (this TypeSpec type)
++ {
++ // LAMESPEC: Arity is not mentioned
++ if (type.Arity > 1)
++ return false;
++
++ var amb = type.MemberDefinition.GetAsyncMethodBuilder ();
++ if (amb == null)
++ return false;
++
++ return amb.Arity == type.Arity;
++ }
++ }
+ }
+diff --git a/mcs/mcs/attribute.cs b/mcs/mcs/attribute.cs
+index 3ff2d68ccb5..83d403118ad 100644
+--- a/mcs/mcs/attribute.cs
++++ b/mcs/mcs/attribute.cs
+@@ -789,6 +789,17 @@ namespace Mono.CSharp {
+ return ((BoolConstant) pos_args[0].Expr).Value;
+ }
+
++ public TypeSpec GetAsyncMethodBuilderValue ()
++ {
++ if (!arg_resolved)
++ Resolve ();
++
++ if (resolve_error)
++ return null;
++
++ return GetArgumentType ();
++ }
++
+ public TypeSpec GetCoClassAttributeValue ()
+ {
+ if (!arg_resolved)
+@@ -1754,9 +1765,11 @@ namespace Mono.CSharp {
+
+ // New in .NET 4.7
+ public readonly PredefinedTupleElementNamesAttribute TupleElementNames;
++ public readonly PredefinedAttribute AsyncMethodBuilder;
+
+ // New in .NET 4.7.1
+ public readonly PredefinedAttribute IsReadOnly;
++ public readonly PredefinedAttribute IsByRefLike;
+
+ //
+ // Optional types which are used as types and for member lookup
+@@ -1837,8 +1850,10 @@ namespace Mono.CSharp {
+ CallerLineNumberAttribute = new PredefinedAttribute (module, "System.Runtime.CompilerServices", "CallerLineNumberAttribute");
+ CallerFilePathAttribute = new PredefinedAttribute (module, "System.Runtime.CompilerServices", "CallerFilePathAttribute");
+
++ AsyncMethodBuilder = new PredefinedAttribute (module, "System.Runtime.CompilerServices", "AsyncMethodBuilderAttribute");
+ TupleElementNames = new PredefinedTupleElementNamesAttribute (module, "System.Runtime.CompilerServices", "TupleElementNamesAttribute");
+ IsReadOnly = new PredefinedAttribute (module, "System.Runtime.CompilerServices", "IsReadOnlyAttribute");
++ IsByRefLike = new PredefinedAttribute (module, "System.Runtime.CompilerServices", "IsByRefLikeAttribute");
+
+ // TODO: Should define only attributes which are used for comparison
+ const System.Reflection.BindingFlags all_fields = System.Reflection.BindingFlags.Public |
+diff --git a/mcs/mcs/class.cs b/mcs/mcs/class.cs
+index 9afb32c6fe5..6b1adc297a3 100644
+--- a/mcs/mcs/class.cs
++++ b/mcs/mcs/class.cs
+@@ -224,6 +224,24 @@ namespace Mono.CSharp
+ }
+ }
+
++ public void CloseContainerEarlyForReflectionEmit ()
++ {
++ if (containers != null) {
++ foreach (TypeContainer tc in containers) {
++ //
++ // SRE requires due to internal checks that any field of enum type is
++ // baked. We close all enum types before closing any other types to
++ // workaround this limitation
++ //
++ if (tc.Kind == MemberKind.Enum) {
++ tc.CloseContainer ();
++ } else {
++ tc.CloseContainerEarlyForReflectionEmit ();
++ }
++ }
++ }
++ }
++
+ public virtual void CreateMetadataName (StringBuilder sb)
+ {
+ if (Parent != null && Parent.MemberName != null)
+@@ -1102,6 +1120,18 @@ namespace Mono.CSharp
+ member.GenerateDocComment (builder);
+ }
+
++ public TypeSpec GetAsyncMethodBuilder ()
++ {
++ if (OptAttributes == null)
++ return null;
++
++ Attribute a = OptAttributes.Search (Module.PredefinedAttributes.AsyncMethodBuilder);
++ if (a == null)
++ return null;
++
++ return a.GetAsyncMethodBuilderValue ();
++ }
++
+ public TypeSpec GetAttributeCoClass ()
+ {
+ if (OptAttributes == null)
+@@ -2171,7 +2201,7 @@ namespace Mono.CSharp
+
+ public override void Emit ()
+ {
+- if (Interfaces != null) {
++ if (Interfaces != null && (ModFlags & Modifiers.PRIVATE) == 0) {
+ foreach (var iface in Interfaces) {
+ if (iface.HasNamedTupleElement) {
+ throw new NotImplementedException ("named tuples for .interfaceimpl");
+@@ -3023,7 +3053,8 @@ namespace Mono.CSharp
+ Modifiers.INTERNAL |
+ Modifiers.UNSAFE |
+ Modifiers.PRIVATE |
+- Modifiers.READONLY;
++ Modifiers.READONLY |
++ Modifiers.REF;
+
+ public Struct (TypeContainer parent, MemberName name, Modifiers mod, Attributes attrs)
+ : base (parent, name, attrs, MemberKind.Struct)
+@@ -3139,6 +3170,9 @@ namespace Mono.CSharp
+ if ((ModFlags & Modifiers.READONLY) != 0)
+ Module.PredefinedAttributes.IsReadOnly.EmitAttribute (TypeBuilder);
+
++ if ((ModFlags & Modifiers.REF) != 0)
++ Module.PredefinedAttributes.IsByRefLike.EmitAttribute (TypeBuilder);
++
+ CheckStructCycles ();
+
+ base.Emit ();
+@@ -3213,6 +3247,10 @@ namespace Mono.CSharp
+ protected override TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
+ {
+ var ifaces = base.ResolveBaseTypes (out base_class);
++ if (ifaces != null && (ModFlags & Modifiers.REF) != 0) {
++ Report.Error (8343, Location, "`{0}': ref structs cannot implement interfaces", GetSignatureForError ());
++ }
++
+ base_type = Compiler.BuiltinTypes.ValueType;
+ return ifaces;
+ }
+@@ -3915,7 +3953,7 @@ namespace Mono.CSharp
+
+ protected void IsTypePermitted ()
+ {
+- if (MemberType.IsSpecialRuntimeType) {
++ if (MemberType.IsSpecialRuntimeType || MemberType.IsByRefLike) {
+ if (Parent is StateMachine) {
+ Report.Error (4012, Location,
+ "Parameters or local variables of type `{0}' cannot be declared in async methods or iterators",
+@@ -3924,6 +3962,19 @@ namespace Mono.CSharp
+ Report.Error (4013, Location,
+ "Local variables of type `{0}' cannot be used inside anonymous methods, lambda expressions or query expressions",
+ MemberType.GetSignatureForError ());
++ } else if (MemberType.IsByRefLike) {
++ if ((ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0)
++ return;
++
++ if ((ModFlags & Modifiers.AutoProperty) == 0 && this is Property)
++ return;
++
++ if ((ModFlags & Modifiers.STATIC) == 0 && (Parent.ModFlags & Modifiers.REF) != 0)
++ return;
++
++ Report.Error (8345, Location,
++ "Field or auto-implemented property cannot be of type `{0}' unless it is an instance member of a ref struct",
++ MemberType.GetSignatureForError ());
+ } else {
+ Report.Error (610, Location,
+ "Field or property cannot be of type `{0}'", MemberType.GetSignatureForError ());
+diff --git a/mcs/mcs/const.cs b/mcs/mcs/const.cs
+index 046aec24c1b..658f15ec57a 100644
+--- a/mcs/mcs/const.cs
++++ b/mcs/mcs/const.cs
+@@ -206,7 +206,9 @@ namespace Mono.CSharp {
+ c = field.ConvertInitializer (rc, c);
+
+ if (c == null) {
+- if (TypeSpec.IsReferenceType (field.MemberType))
++ if (expr is DefaultLiteralExpression) {
++ // It's handled bellow in New.Constantify
++ } else if (TypeSpec.IsReferenceType (field.MemberType))
+ Error_ConstantCanBeInitializedWithNullOnly (rc, field.MemberType, expr.Location, GetSignatureForError ());
+ else if (!(expr is Constant))
+ Error_ExpressionMustBeConstant (rc, expr.Location, GetSignatureForError ());
+diff --git a/mcs/mcs/convert.cs b/mcs/mcs/convert.cs
+index b11477c1043..ae153fc49e8 100644
+--- a/mcs/mcs/convert.cs
++++ b/mcs/mcs/convert.cs
+@@ -392,6 +392,9 @@ namespace Mono.CSharp {
+ if (!TypeSpec.IsValueType (expr_type))
+ return null;
+
++ if (expr_type.IsByRefLike)
++ return null;
++
+ return expr == null ? EmptyExpression.Null : new BoxedCast (expr, target_type);
+
+ case BuiltinTypeSpec.Type.Enum:
+@@ -816,7 +819,7 @@ namespace Mono.CSharp {
+ if (expr_type == target_type)
+ return true;
+
+- if (expr_type == InternalType.ThrowExpr)
++ if (expr_type == InternalType.ThrowExpr || expr_type == InternalType.DefaultType)
+ return target_type.Kind != MemberKind.InternalCompilerType;
+
+ if (target_type.IsNullableType)
+@@ -1478,6 +1481,10 @@ namespace Mono.CSharp {
+ return target_type.Kind == MemberKind.InternalCompilerType ? null : EmptyCast.Create (expr, target_type);
+ }
+
++ if (expr_type == InternalType.DefaultType) {
++ return new DefaultValueExpression (new TypeExpression (target_type, expr.Location), expr.Location).Resolve (ec);
++ }
++
+ if (target_type.IsNullableType)
+ return ImplicitNulableConversion (ec, expr, target_type);
+
+@@ -1967,7 +1974,7 @@ namespace Mono.CSharp {
+ // From object or dynamic to any reference type or value type (unboxing)
+ //
+ if (source_type.BuiltinType == BuiltinTypeSpec.Type.Object || source_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
+- if (target_type.IsPointer)
++ if (target_type.IsPointer || target_type.IsByRefLike)
+ return null;
+
+ return
+diff --git a/mcs/mcs/cs-parser.jay b/mcs/mcs/cs-parser.jay
+index 2868d2fd8f6..4d6fcb44c0d 100644
+--- a/mcs/mcs/cs-parser.jay
++++ b/mcs/mcs/cs-parser.jay
+@@ -169,7 +169,8 @@ namespace Mono.CSharp
+ %token CONST
+ %token CONTINUE
+ %token DECIMAL
+-%token DEFAULT
++%token DEFAULT
++%token DEFAULT_VALUE
+ %token DELEGATE
+ %token DO
+ %token DOUBLE
+@@ -336,6 +337,7 @@ namespace Mono.CSharp
+ %token DEFAULT_COLON
+ %token OPEN_BRACKET_EXPR
+ %token OPEN_PARENS_DECONSTRUCT
++%token REF_STRUCT
+
+ // Make the parser go into eval mode parsing (statements and compilation units).
+ %token EVAL_STATEMENT_PARSER
+@@ -863,7 +865,7 @@ attribute_arguments
+ }
+
+ Arguments args = ((Arguments) o [0]);
+- if (args.Count > 0 && !($3 is NamedArgument) && args [args.Count - 1] is NamedArgument)
++ if (lang_version < LanguageVersion.V_7_2 && args.Count > 0 && !($3 is NamedArgument) && args [args.Count - 1] is NamedArgument)
+ Error_NamedArgumentExpected ((NamedArgument) args [args.Count - 1]);
+
+ args.Add ((Argument) $3);
+@@ -1015,17 +1017,34 @@ primary_constructor_body
+ }
+ ;
+
++struct_keyword
++ : STRUCT
++ {
++ $$ = null;
++ }
++ | REF_STRUCT
++ {
++ if (lang_version < LanguageVersion.V_7_2) {
++ FeatureIsNotAvailable (GetLocation ($1), "ref structs");
++ }
++
++ $$ = this;
++ }
++ ;
++
+ struct_declaration
+ : opt_attributes
+ opt_modifiers
+ opt_partial
+- STRUCT
++ struct_keyword
+ type_declaration_name
+ {
+ var mods = (Modifiers) $2;
+ if ((mods & Modifiers.READONLY) != 0 && lang_version < LanguageVersion.V_7_2) {
+ FeatureIsNotAvailable (GetLocation ($4), "readonly structs");
+ }
++ if ($4 != null)
++ mods |= Modifiers.REF;
+
+ lexer.ConstraintsParsing = true;
+ valid_param_mod = ParameterModifierType.PrimaryConstructor;
+@@ -1071,7 +1090,7 @@ struct_declaration
+ }
+ $$ = pop_current_class ();
+ }
+- | opt_attributes opt_modifiers opt_partial STRUCT error
++ | opt_attributes opt_modifiers opt_partial struct_keyword error
+ {
+ Error_SyntaxError (yyToken);
+ }
+@@ -1384,6 +1403,18 @@ ref_member_type
+
+ $$ = new ReferenceTypeExpr ((FullNamedExpression) $3, GetLocation ($1));
+ }
++ | REF READONLY
++ {
++ lexer.parsing_generic_declaration = true;
++ }
++ type
++ {
++ if (lang_version < LanguageVersion.V_7_2) {
++ FeatureIsNotAvailable (GetLocation ($2), "readonly references");
++ }
++
++ $$ = new ReferenceTypeExpr ((FullNamedExpression) $4, true, GetLocation ($1));
++ }
+ ;
+
+ method_header
+@@ -3448,6 +3479,7 @@ primary_expression
+ | anonymous_method_expression
+ | undocumented_expressions
+ | interpolated_string
++ | default_literal
+ ;
+
+ type_name_expression
+@@ -3824,7 +3856,7 @@ argument_list
+ | argument_list COMMA argument
+ {
+ Arguments list = (Arguments) $1;
+- if (list [list.Count - 1] is NamedArgument)
++ if (lang_version < LanguageVersion.V_7_2 && list [list.Count - 1] is NamedArgument)
+ Error_NamedArgumentExpected ((NamedArgument) list [list.Count - 1]);
+
+ list.Add ((Argument) $3);
+@@ -3969,7 +4001,7 @@ expression_list_arguments
+ | expression_list_arguments COMMA expression_list_argument
+ {
+ Arguments args = (Arguments) $1;
+- if (args [args.Count - 1] is NamedArgument && !($3 is NamedArgument))
++ if (lang_version < LanguageVersion.V_7_2 && args [args.Count - 1] is NamedArgument && !($3 is NamedArgument))
+ Error_NamedArgumentExpected ((NamedArgument) args [args.Count - 1]);
+
+ args.Add ((Argument) $3);
+@@ -4386,7 +4418,7 @@ anonymous_method_signature
+ ;
+
+ default_value_expression
+- : DEFAULT open_parens_any type CLOSE_PARENS
++ : DEFAULT_VALUE open_parens_any type CLOSE_PARENS
+ {
+ if (lang_version < LanguageVersion.ISO_2)
+ FeatureIsNotAvailable (GetLocation ($1), "default value expression");
+@@ -4396,6 +4428,16 @@ default_value_expression
+ }
+ ;
+
++default_literal
++ : DEFAULT
++ {
++ if (lang_version < LanguageVersion.V_7_1)
++ FeatureIsNotAvailable (GetLocation ($1), "default literal");
++
++ $$ = new DefaultLiteralExpression (GetLocation ($1));
++ }
++ ;
++
+ unary_expression
+ : primary_expression
+ | BANG prefixed_unary_expression
+@@ -4750,7 +4792,7 @@ pattern_list
+ | pattern_list COMMA pattern_argument
+ {
+ Arguments args = (Arguments) $1;
+- if (args [args.Count - 1] is NamedArgument && !($3 is NamedArgument))
++ if (lang_version < LanguageVersion.V_7_2 && args [args.Count - 1] is NamedArgument && !($3 is NamedArgument))
+ Error_NamedArgumentExpected ((NamedArgument) args [args.Count - 1]);
+
+ args.Add ((Argument) $3);
+@@ -5067,17 +5109,25 @@ assignment_expression
+ $$ = new CompoundAssign (Binary.Operator.ExclusiveOr, (Expression) $1, (Expression) $3);
+ lbag.AddLocation ($$, GetLocation ($2));
+ }
+- | OPEN_PARENS_DECONSTRUCT deconstruct_exprs CLOSE_PARENS ASSIGN expression
++ | OPEN_PARENS_DECONSTRUCT deconstruct_assignment CLOSE_PARENS ASSIGN expression
+ {
+ if (lang_version < LanguageVersion.V_7)
+ FeatureIsNotAvailable (GetLocation ($1), "tuples");
+
+- var exprs = (List<Expression>) $2;
++ var exprs = (List<Expression>) $2;
++ $$ = new TupleDeconstruct (exprs, (Expression) $5, GetLocation ($4));
++ }
++ | OPEN_PARENS_DECONSTRUCT deconstruct_declaration CLOSE_PARENS ASSIGN expression
++ {
++ if (lang_version < LanguageVersion.V_7)
++ FeatureIsNotAvailable (GetLocation ($1), "tuples");
++
++ var exprs = (List<BlockVariable>) $2;
+ $$ = new TupleDeconstruct (exprs, (Expression) $5, GetLocation ($4));
+ }
+ ;
+
+-deconstruct_exprs
++deconstruct_assignment
+ : expression COMMA expression
+ {
+ $$ = new List<Expression> () {
+@@ -5085,7 +5135,7 @@ deconstruct_exprs
+ (Expression) $3
+ };
+ }
+- | deconstruct_exprs COMMA expression
++ | deconstruct_assignment COMMA expression
+ {
+ var src = (List<Expression>) $1;
+ src.Add ((Expression) $3);
+@@ -5093,6 +5143,43 @@ deconstruct_exprs
+ }
+ ;
+
++deconstruct_declaration
++ : variable_type identifier_inside_body
++ {
++ var lt = (LocatedToken) $2;
++ var li = new LocalVariable (current_block, lt.Value, lt.Location);
++ current_block.AddLocalName (li);
++ $$ = new List<BlockVariable> (2) {
++ new BlockVariable ((FullNamedExpression) $1, li)
++ };
++ }
++ | deconstruct_declaration COMMA variable_type identifier_inside_body
++ {
++ var lt = (LocatedToken) $4;
++ var li = new LocalVariable (current_block, lt.Value, lt.Location);
++ current_block.AddLocalName (li);
++
++ var src = (List<BlockVariable>) $1;
++ src.Add (new BlockVariable ((FullNamedExpression) $3, li));
++ $$ = src;
++ }
++ | deconstruct_declaration COMMA identifier_inside_body
++ {
++ var lt = (LocatedToken) $3;
++ var li = new LocalVariable (current_block, lt.Value, lt.Location);
++
++ if (lt.Value != "_") {
++ report.Error (8184, lt.Location, "A deconstruction cannot mix declarations and expressions on the left-hand-side");
++ } else {
++ li.Type = InternalType.Discard;
++ }
++
++ var src = (List<BlockVariable>) $1;
++ src.Add (new BlockVariable (new TypeExpression (li.Type, lt.Location), li));
++ $$ = src;
++ }
++ ;
++
+ lambda_parameter_list
+ : lambda_parameter
+ {
+@@ -6008,6 +6095,28 @@ block_variable_declaration
+ lbag.AddLocation ($$, GetLocation ($7));
+ }
+ }
++ | REF READONLY variable_type identifier_inside_body
++ {
++ if (lang_version < LanguageVersion.V_7_2) {
++ FeatureIsNotAvailable (GetLocation ($2), "readonly references");
++ }
++
++ var lt = (LocatedToken) $4;
++ var li = new LocalVariable (current_block, lt.Value, LocalVariable.Flags.ByRef | LocalVariable.Flags.ReadonlyMask, lt.Location);
++ current_block.AddLocalName (li);
++ current_variable = new BlockVariable ((FullNamedExpression) $3, li);
++ }
++ opt_local_variable_initializer opt_variable_declarators SEMICOLON
++ {
++ $$ = current_variable;
++ current_variable = null;
++ if ($6 != null) {
++ lbag.AddLocation ($$, PopLocation (), GetLocation ($8));
++ } else {
++ report.Error (8174, GetLocation ($3), "A declaration of a by-reference variable must have an initializer");
++ lbag.AddLocation ($$, GetLocation ($8));
++ }
++ }
+ ;
+
+ opt_local_variable_initializer
+@@ -7731,7 +7840,7 @@ void Warning_EmptyStatement (Location loc)
+
+ void Error_NamedArgumentExpected (NamedArgument a)
+ {
+- report.Error (1738, a.Location, "Named arguments must appear after the positional arguments");
++ report.Error (1738, a.Location, "Named arguments must appear after the positional arguments when using language version older than 7.2");
+ }
+
+ void Error_MissingInitializer (Location loc)
+@@ -8255,6 +8364,7 @@ static string GetTokenName (int token)
+ case Token.CONTINUE:
+ return "continue";
+ case Token.DEFAULT:
++ case Token.DEFAULT_VALUE:
+ return "default";
+ case Token.DELEGATE:
+ return "delegate";
+@@ -8334,6 +8444,7 @@ static string GetTokenName (int token)
+ case Token.STATIC:
+ return "static";
+ case Token.STRUCT:
++ case Token.REF_STRUCT:
+ return "struct";
+ case Token.SWITCH:
+ return "switch";
+diff --git a/mcs/mcs/cs-tokenizer.cs b/mcs/mcs/cs-tokenizer.cs
+index d6d00d31400..37edb5c1224 100644
+--- a/mcs/mcs/cs-tokenizer.cs
++++ b/mcs/mcs/cs-tokenizer.cs
+@@ -716,9 +716,18 @@ namespace Mono.CSharp
+ res = Token.EXTERN_ALIAS;
+ break;
+ case Token.DEFAULT:
+- if (peek_token () == Token.COLON) {
+- token ();
+- res = Token.DEFAULT_COLON;
++ switch (peek_token ()) {
++ case Token.COLON:
++ // Special case: foo == null ? default : 1;
++ if (current_token != Token.INTERR) {
++ token ();
++ res = Token.DEFAULT_COLON;
++ }
++ break;
++ case Token.OPEN_PARENS:
++ case Token.OPEN_PARENS_CAST:
++ res = Token.DEFAULT_VALUE;
++ break;
+ }
+ break;
+ case Token.WHEN:
+@@ -812,10 +821,12 @@ namespace Mono.CSharp
+ PushPosition ();
+
+ next_token = token ();
+- bool ok = (next_token == Token.CLASS) ||
+- (next_token == Token.STRUCT) ||
+- (next_token == Token.INTERFACE) ||
+- (next_token == Token.VOID);
++ bool ok =
++ next_token == Token.CLASS ||
++ next_token == Token.STRUCT ||
++ next_token == Token.INTERFACE ||
++ next_token == Token.VOID ||
++ next_token == Token.REF_STRUCT;
+
+ PopPosition ();
+
+@@ -903,6 +914,12 @@ namespace Mono.CSharp
+ break;
+ }
+
++ break;
++ case Token.REF:
++ if (peek_token () == Token.STRUCT) {
++ token ();
++ res = Token.REF_STRUCT;
++ }
+ break;
+ }
+
+@@ -1094,6 +1111,7 @@ namespace Mono.CSharp
+ case Token.UNCHECKED:
+ case Token.UNSAFE:
+ case Token.DEFAULT:
++ case Token.DEFAULT_VALUE:
+ case Token.AWAIT:
+
+ //
+@@ -1273,14 +1291,21 @@ namespace Mono.CSharp
+
+ return false;
+ case Token.OPEN_PARENS:
+- if (!parsing_generic_declaration)
+- return false;
+-
++ int parens_count = 1;
+ while (true) {
+ switch (token ()) {
+ case Token.COMMA:
+ // tuple declaration after <
+- return true;
++ if (parens_count == 1)
++ return true;
++ continue;
++ case Token.OPEN_PARENS:
++ ++parens_count;
++ continue;
++ case Token.CLOSE_PARENS:
++ if (--parens_count <= 0)
++ return false;
++ continue;
+ case Token.OP_GENERICS_GT:
+ case Token.EOF:
+ return false;
+@@ -1380,6 +1405,7 @@ namespace Mono.CSharp
+ case Token.NEW:
+ case Token.INTERPOLATED_STRING:
+ case Token.THROW:
++ case Token.DEFAULT_COLON:
+ next_token = Token.INTERR;
+ break;
+
+@@ -3502,6 +3528,7 @@ namespace Mono.CSharp
+ case Token.SWITCH:
+ case Token.USING:
+ case Token.DEFAULT:
++ case Token.DEFAULT_VALUE:
+ case Token.DELEGATE:
+ case Token.OP_GENERICS_GT:
+ case Token.REFVALUE:
+@@ -3963,26 +3990,29 @@ namespace Mono.CSharp
+ {
+ int d;
+
+- // Save current position and parse next token.
+- PushPosition ();
+- int generic_dimension = 0;
+- if (parse_less_than (ref generic_dimension)) {
+- if (parsing_generic_declaration && (parsing_generic_declaration_doc || token () != Token.DOT)) {
+- d = Token.OP_GENERICS_LT_DECL;
+- } else {
+- if (generic_dimension > 0) {
+- val = generic_dimension;
+- DiscardPosition ();
+- return Token.GENERIC_DIMENSION;
+- }
++ if (current_token != Token.OPERATOR) {
++ // Save current position and parse next token.
++ PushPosition ();
++ int generic_dimension = 0;
++ if (parse_less_than (ref generic_dimension)) {
++ if (parsing_generic_declaration && (parsing_generic_declaration_doc || token () != Token.DOT)) {
++ d = Token.OP_GENERICS_LT_DECL;
++ } else {
++ if (generic_dimension > 0) {
++ val = generic_dimension;
++ DiscardPosition ();
++ return Token.GENERIC_DIMENSION;
++ }
+
+- d = Token.OP_GENERICS_LT;
++ d = Token.OP_GENERICS_LT;
++ }
++ PopPosition ();
++ return d;
+ }
++
+ PopPosition ();
+- return d;
+ }
+
+- PopPosition ();
+ parsing_generic_less_than = 0;
+
+ d = peek_char ();
+diff --git a/mcs/mcs/delegate.cs b/mcs/mcs/delegate.cs
+index 80eb7e265f1..52cee8f3455 100644
+--- a/mcs/mcs/delegate.cs
++++ b/mcs/mcs/delegate.cs
+@@ -188,8 +188,8 @@ namespace Mono.CSharp {
+
+ CheckProtectedModifier ();
+
+- if (Compiler.Settings.StdLib && ret_type.IsSpecialRuntimeType) {
+- Method.Error1599 (Location, ret_type, Report);
++ if (ret_type.IsSpecialRuntimeType && Compiler.Settings.StdLib) {
++ Method.Error_ReturnTypeCantBeRefAny (Location, ret_type, Report);
+ return false;
+ }
+
+@@ -338,6 +338,8 @@ namespace Mono.CSharp {
+ Module.PredefinedAttributes.Dynamic.EmitAttribute (CreateReturnBuilder ().Builder);
+ } else if (rtype.HasDynamicElement) {
+ Module.PredefinedAttributes.Dynamic.EmitAttribute (CreateReturnBuilder ().Builder, rtype, Location);
++ } else if (rtype is ReadOnlyReferenceContainer) {
++ Module.PredefinedAttributes.IsReadOnly.EmitAttribute (CreateReturnBuilder ().Builder);
+ }
+
+ if (rtype.HasNamedTupleElement) {
+@@ -603,8 +605,14 @@ namespace Mono.CSharp {
+ }
+
+ var expr = method_group.InstanceExpression;
+- if (expr != null && (expr.Type.IsGenericParameter || !TypeSpec.IsReferenceType (expr.Type)))
++ if (expr != null && (expr.Type.IsGenericParameter || !TypeSpec.IsReferenceType (expr.Type))) {
++ if (expr.Type.IsByRefLike || expr.Type.IsSpecialRuntimeType) {
++ // CSC: Should be better error code
++ Error_ConversionFailed (ec, delegate_method, null);
++ }
++
+ method_group.InstanceExpression = new BoxedCast (expr, ec.BuiltinTypes.Object);
++ }
+
+ eclass = ExprClass.Value;
+ return this;
+diff --git a/mcs/mcs/dynamic.cs b/mcs/mcs/dynamic.cs
+index fd4662b2fed..f8314b2f3cd 100644
+--- a/mcs/mcs/dynamic.cs
++++ b/mcs/mcs/dynamic.cs
+@@ -279,11 +279,19 @@ namespace Mono.CSharp
+
+ protected bool DoResolveCore (ResolveContext rc)
+ {
++ int i = 0;
+ foreach (var arg in arguments) {
+ if (arg.Type == InternalType.VarOutType) {
+ // Should be special error message about dynamic dispatch
+ rc.Report.Error (8197, arg.Expr.Location, "Cannot infer the type of implicitly-typed out variable `{0}'", ((DeclarationExpression) arg.Expr).Variable.Name);
++ } else if (arg.Type == InternalType.DefaultType) {
++ rc.Report.Error (8311, arg.Expr.Location, "Cannot use a default literal as an argument to a dynamically dispatched operation");
+ }
++
++ // Forced limitation because Microsoft.CSharp needs to catch up
++ if (i > 0 && arguments [i - 1] is NamedArgument && !(arguments [i] is NamedArgument))
++ rc.Report.Error (8324, loc, "Named argument specifications must appear after all fixed arguments have been specified in a dynamic invocation");
++ ++i;
+ }
+
+ if (rc.CurrentTypeParameters != null && rc.CurrentTypeParameters[0].IsMethodTypeParameter)
+diff --git a/mcs/mcs/ecore.cs b/mcs/mcs/ecore.cs
+index 34ff9a30dab..20ee9e73b19 100644
+--- a/mcs/mcs/ecore.cs
++++ b/mcs/mcs/ecore.cs
+@@ -255,7 +255,7 @@ namespace Mono.CSharp {
+
+ public void Error_ExpressionMustBeConstant (ResolveContext rc, Location loc, string e_name)
+ {
+- rc.Report.Error (133, loc, "The expression being assigned to `{0}' must be constant", e_name);
++ rc.Report.Error (133, loc, "The expression being assigned to `{0}' must be a constant or default value", e_name);
+ }
+
+ public void Error_ConstantCanBeInitializedWithNullOnly (ResolveContext rc, TypeSpec type, Location loc, string name)
+@@ -2957,6 +2957,13 @@ namespace Mono.CSharp {
+ if ((restrictions & MemberLookupRestrictions.NameOfExcluded) == 0 && Name == "nameof")
+ return new NameOf (this);
+
++ if ((restrictions & MemberLookupRestrictions.ReadAccess) == 0 && Name == "_") {
++ if (rc.Module.Compiler.Settings.Version < LanguageVersion.V_7)
++ rc.Report.FeatureIsNotAvailable (rc.Module.Compiler, loc, "discards");
++
++ return new Discard (loc).Resolve (rc);
++ }
++
+ if (errorMode) {
+ if (variable_found) {
+ rc.Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", Name);
+@@ -4029,6 +4036,13 @@ namespace Mono.CSharp {
+ return Methods.First ().GetSignatureForError ();
+ }
+
++ static MethodSpec CandidateDevirtualization (TypeSpec type, MethodSpec method)
++ {
++ // Assumes no generics get involved
++ var filter = new MemberFilter (method.Name, method.Arity, MemberKind.Method, method.Parameters, null);
++ return MemberCache.FindMember (type, filter, BindingRestriction.InstanceOnly | BindingRestriction.OverrideOnly | BindingRestriction.DeclaredOnly) as MethodSpec;
++ }
++
+ public override Expression CreateExpressionTree (ResolveContext ec)
+ {
+ if (best_candidate == null) {
+@@ -4177,6 +4191,22 @@ namespace Mono.CSharp {
+ }
+
+ InstanceExpression.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup | ResolveFlags.Type);
++
++ var expr_type = InstanceExpression.Type;
++ if ((expr_type.IsByRefLike || expr_type.IsSpecialRuntimeType) && best_candidate.DeclaringType != expr_type) {
++ MethodSpec devirt = null;
++ if ((best_candidate.Modifiers & (Modifiers.VIRTUAL | Modifiers.ABSTRACT | Modifiers.OVERRIDE)) != 0) {
++ devirt = CandidateDevirtualization (expr_type, best_candidate);
++ }
++
++ if (devirt == null) {
++ // CSC: Should be better error message
++ ec.Report.Error (29, InstanceExpression.Location, "Cannot implicitly convert type `{0}' to `{1}'",
++ InstanceExpression.Type.GetSignatureForError (), best_candidate.DeclaringType.GetSignatureForError ());
++ } else {
++ best_candidate = devirt;
++ }
++ }
+ }
+ }
+
+@@ -5419,7 +5449,7 @@ namespace Mono.CSharp {
+ }
+
+ if (arg_type != parameter) {
+- if (arg_type == InternalType.VarOutType)
++ if (arg_type == InternalType.VarOutType || arg_type == InternalType.Discard)
+ return 0;
+
+ var ref_arg_type = arg_type as ReferenceContainer;
+@@ -6028,6 +6058,11 @@ namespace Mono.CSharp {
+ continue;
+ }
+
++ if (arg_type == InternalType.Discard) {
++ a.Expr.Type = pt;
++ continue;
++ }
++
+ var ref_arg_type = arg_type as ReferenceContainer;
+ if (ref_arg_type != null) {
+ if (ref_arg_type.Element != pt)
+@@ -6061,9 +6096,15 @@ namespace Mono.CSharp {
+ else
+ ec.Report.SymbolRelatedToPreviousError (member);
+
+- ec.Report.Error (1744, na.Location,
+- "Named argument `{0}' cannot be used for a parameter which has positional argument specified",
+- na.Name);
++ if (name_index > a_idx) {
++ ec.Report.Error (8323, na.Location,
++ "Named argument `{0}' is used out of position but is followed by positional argument",
++ na.Name);
++ } else {
++ ec.Report.Error (1744, na.Location,
++ "Named argument `{0}' cannot be used for a parameter which has positional argument specified",
++ na.Name);
++ }
+ }
+ }
+
+@@ -7350,6 +7391,9 @@ namespace Mono.CSharp {
+ if (!ResolveGetter (ec))
+ return null;
+
++ if (type.Kind == MemberKind.ByRef)
++ return ByRefDereference.Create (this).Resolve (ec);
++
+ return this;
+ }
+
+@@ -7359,12 +7403,11 @@ namespace Mono.CSharp {
+ Error_NullPropagatingLValue (rc);
+
+ if (right_side == EmptyExpression.OutAccess) {
+- if (best_candidate?.MemberType.Kind == MemberKind.ByRef) {
+- if (Arguments?.ContainsEmitWithAwait () == true) {
+- rc.Report.Error (8178, loc, "`await' cannot be used in an expression containing a call to `{0}' because it returns by reference",
+- GetSignatureForError ());
+- }
++ if (OverloadResolve (rc, null) == null)
++ return null;
+
++ if (best_candidate?.MemberType.Kind == MemberKind.ByRef) {
++ getter = CandidateToBaseOverride (rc, best_candidate.Get);
+ return this;
+ }
+
+@@ -7396,7 +7439,7 @@ namespace Mono.CSharp {
+
+ if (best_candidate.MemberType.Kind == MemberKind.ByRef) {
+ getter = CandidateToBaseOverride (rc, best_candidate.Get);
+- return ByRefDereference.Create(this).Resolve(rc);
++ return ByRefDereference.Create (this).Resolve (rc);
+ }
+
+ rc.Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read-only)",
+diff --git a/mcs/mcs/eval.cs b/mcs/mcs/eval.cs
+index 60e0c6d64a0..075697bb1df 100644
+--- a/mcs/mcs/eval.cs
++++ b/mcs/mcs/eval.cs
+@@ -788,6 +788,7 @@ namespace Mono.CSharp
+ return null;
+ }
+
++ module.CloseContainerEarlyForReflectionEmit ();
+ module.CloseContainer ();
+ if (host != null)
+ host.CloseContainer ();
+diff --git a/mcs/mcs/expression.cs b/mcs/mcs/expression.cs
+index 732ee3ee934..518ccc8ef43 100644
+--- a/mcs/mcs/expression.cs
++++ b/mcs/mcs/expression.cs
+@@ -1220,6 +1220,7 @@ namespace Mono.CSharp
+ expr = expr.ResolveLValue (ec, expr);
+ } else {
+ ec.Report.Error (1059, loc, "The operand of an increment or decrement operator must be a variable, property or indexer");
++ return null;
+ }
+
+ //
+@@ -1477,6 +1478,11 @@ namespace Mono.CSharp
+ return null;
+ }
+
++ if (expr.Type == InternalType.DefaultType) {
++ Error_OperatorCannotBeApplied (rc, loc, OperatorName, expr.Type);
++ return null;
++ }
++
+ return this;
+ }
+
+@@ -4304,9 +4310,32 @@ namespace Mono.CSharp
+ CheckOutOfRangeComparison (ec, rc, left.Type);
+ }
+
+- if (left.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic || right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
++ var ltype = left.Type;
++ var rtype = right.Type;
++ if (ltype.BuiltinType == BuiltinTypeSpec.Type.Dynamic || rtype.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
+ return DoResolveDynamic (ec);
+
++ //
++ // Only default with == and != is explicitly allowed
++ //
++ if (ltype == InternalType.DefaultType || rtype == InternalType.DefaultType) {
++ if ((Oper & Operator.EqualityMask) == 0) {
++ ec.Report.Error (8310, loc, "Operator `{0}' cannot be applied to operand `default'", OperName (Oper));
++ return null;
++ }
++
++ if (ltype == rtype) {
++ ec.Report.Error (8315, loc, "Operator `{0}' is ambiguous on operands `default' and `default'", OperName (Oper));
++ return null;
++ }
++
++ if (rtype == InternalType.DefaultType) {
++ right = new DefaultValueExpression (new TypeExpression (ltype, right.Location), right.Location).Resolve (ec);
++ } else {
++ left = new DefaultValueExpression (new TypeExpression (rtype, left.Location), left.Location).Resolve (ec);
++ }
++ }
++
+ return DoResolveCore (ec, left, right);
+ }
+
+@@ -6744,10 +6773,14 @@ namespace Mono.CSharp
+ ec.Report.Error (1764, loc,
+ "Cannot use fixed variable `{0}' inside an anonymous method, lambda expression or query expression",
+ GetSignatureForError ());
+- } else if (local_info.IsByRef) {
+- ec.Report.Error (8175, loc,
+- "Cannot use by-reference variable `{0}' inside an anonymous method, lambda expression, or query expression",
+- GetSignatureForError ());
++ } else if (local_info.IsByRef || local_info.Type.IsByRefLike) {
++ if (ec.CurrentAnonymousMethod is StateMachineInitializer) {
++ // It's reported later as 4012/4013
++ } else {
++ ec.Report.Error (8175, loc,
++ "Cannot use by-reference variable `{0}' inside an anonymous method, lambda expression, or query expression",
++ GetSignatureForError ());
++ }
+ }
+
+ if (ec.IsVariableCapturingRequired) {
+@@ -6783,7 +6816,9 @@ namespace Mono.CSharp
+ local_info.SetIsUsed ();
+
+ if (local_info.IsReadonly && !ec.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.UsingInitializerScope)) {
+- if (rhs == EmptyExpression.LValueMemberAccess) {
++ if (local_info.IsByRef) {
++ // OK because it cannot be reassigned
++ } else if (rhs == EmptyExpression.LValueMemberAccess) {
+ // CS1654 already reported
+ } else {
+ int code;
+@@ -7175,8 +7210,7 @@ namespace Mono.CSharp
+ {
+ var sn = expr as SimpleName;
+ if (sn != null && sn.Name == "var" && sn.Arity == 0 && arguments?.Count > 1) {
+- var targets = new List<Expression> (arguments.Count);
+- var variables = new List<LocalVariable> (arguments.Count);
++ var variables = new List<BlockVariable> (arguments.Count);
+ foreach (var arg in arguments) {
+ var arg_sn = arg.Expr as SimpleName;
+ if (arg_sn == null || arg_sn.Arity != 0) {
+@@ -7186,12 +7220,10 @@ namespace Mono.CSharp
+
+ var lv = new LocalVariable (rc.CurrentBlock, arg_sn.Name, arg.Expr.Location);
+ rc.CurrentBlock.AddLocalName (lv);
+- variables.Add (lv);
+-
+- targets.Add (new LocalVariableReference (lv, arg_sn.Location));
++ variables.Add (new BlockVariable (new VarExpr (lv.Location), lv));
+ }
+
+- var res = new TupleDeconstruct (targets, variables, right_side, loc);
++ var res = new TupleDeconstruct (variables, right_side, loc);
+ return res.Resolve (rc);
+ }
+
+@@ -7306,15 +7338,8 @@ namespace Mono.CSharp
+
+ eclass = ExprClass.Value;
+
+- if (type.Kind == MemberKind.ByRef) {
+- if (rhs == null && arguments?.ContainsEmitWithAwait () == true) {
+- ec.Report.Error (8178, loc, "`await' cannot be used in an expression containing a call to `{0}' because it returns by reference",
+- GetSignatureForError ());
+- }
+-
+- if (rhs != EmptyExpression.OutAccess)
+- return ByRefDereference.Create (this).Resolve (ec);
+- }
++ if (type.Kind == MemberKind.ByRef && rhs != EmptyExpression.OutAccess)
++ return ByRefDereference.Create (this).Resolve (ec);
+
+ return this;
+ }
+@@ -9034,7 +9059,7 @@ namespace Mono.CSharp
+ if (eclass == ExprClass.Unresolved)
+ ResolveBase (ec);
+
+- if (type.IsClass || type.IsReadOnly) {
++ if (type.IsClass || (type.IsReadOnly && !ec.HasSet (ResolveContext.Options.ConstructorScope))) {
+ if (right_side == EmptyExpression.UnaryAddress)
+ ec.Report.Error (459, loc, "Cannot take the address of `this' because it is read-only");
+ else if (right_side == EmptyExpression.OutAccess)
+@@ -9908,7 +9933,7 @@ namespace Mono.CSharp
+ public static bool IsValidDotExpression (TypeSpec type)
+ {
+ const MemberKind dot_kinds = MemberKind.Class | MemberKind.Struct | MemberKind.Delegate | MemberKind.Enum |
+- MemberKind.Interface | MemberKind.TypeParameter | MemberKind.ArrayType;
++ MemberKind.Interface | MemberKind.TypeParameter | MemberKind.ArrayType | MemberKind.ByRef;
+
+ return (type.Kind & dot_kinds) != 0 || type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
+ }
+@@ -11614,7 +11639,7 @@ namespace Mono.CSharp
+ }
+
+ if (single_spec != null && single_spec.Dimension > 0) {
+- if (type.IsSpecialRuntimeType) {
++ if (type.IsSpecialRuntimeType || type.IsByRefLike) {
+ ec.Module.Compiler.Report.Error (611, loc, "Array elements cannot be of type `{0}'", type.GetSignatureForError ());
+ } else if (type.IsStatic) {
+ ec.Module.Compiler.Report.SymbolRelatedToPreviousError (type);
+@@ -11650,6 +11675,13 @@ namespace Mono.CSharp
+ class ReferenceTypeExpr : TypeExpr
+ {
+ FullNamedExpression element;
++ readonly bool readOnly;
++
++ public ReferenceTypeExpr (FullNamedExpression element, bool readOnly, Location loc)
++ : this (element, loc)
++ {
++ this.readOnly = readOnly;
++ }
+
+ public ReferenceTypeExpr (FullNamedExpression element, Location loc)
+ {
+@@ -11664,14 +11696,17 @@ namespace Mono.CSharp
+ return null;
+
+ eclass = ExprClass.Type;
+- type = ReferenceContainer.MakeType (mc.Module, type);
++ type = readOnly ?
++ ReadOnlyReferenceContainer.MakeType (mc.Module, type) :
++ ReferenceContainer.MakeType (mc.Module, type);
+
+ return type;
+ }
+
+ public override string GetSignatureForError ()
+ {
+- return "ref " + element.GetSignatureForError ();
++ var prefix = readOnly ? "ref " : "ref readonly ";
++ return prefix + element.GetSignatureForError ();
+ }
+
+ public override object Accept (StructuralVisitor visitor)
+@@ -11783,6 +11818,7 @@ namespace Mono.CSharp
+ TypeSpec otype;
+ Expression texpr;
+ Expression count;
++ MethodSpec ctor;
+
+ public StackAlloc (Expression type, Expression count, Location l)
+ {
+@@ -11852,6 +11888,11 @@ namespace Mono.CSharp
+ int size = BuiltinTypeSpec.GetSize (otype);
+
+ count.Emit (ec);
++ bool count_on_stack = false;
++ if (ctor != null && !ExpressionAnalyzer.IsInexpensiveLoad (count)) {
++ ec.Emit (OpCodes.Dup);
++ count_on_stack = true;
++ }
+
+ if (size == 0)
+ ec.Emit (OpCodes.Sizeof, otype);
+@@ -11860,6 +11901,19 @@ namespace Mono.CSharp
+
+ ec.Emit (OpCodes.Mul_Ovf_Un);
+ ec.Emit (OpCodes.Localloc);
++
++ if (ctor != null) {
++ if (!count_on_stack)
++ count.Emit (ec);
++ ec.Emit (OpCodes.Newobj, ctor);
++ }
++ }
++
++ public override void Error_ValueCannotBeConverted (ResolveContext rc, TypeSpec target, bool expl)
++ {
++ var etype = ((PointerContainer)type).Element;
++ rc.Report.Error (8346, loc, "Cannot convert a stackalloc expression of type `{0}' to type `{1}'",
++ etype.GetSignatureForError (), target.GetSignatureForError ());
+ }
+
+ protected override void CloneTo (CloneContext clonectx, Expression t)
+@@ -11873,6 +11927,16 @@ namespace Mono.CSharp
+ {
+ return visitor.Visit (this);
+ }
++
++ public bool ResolveSpanConversion (ResolveContext rc, TypeSpec spanType)
++ {
++ ctor = MemberCache.FindMember (spanType, MemberFilter.Constructor (ParametersCompiled.CreateFullyResolved (PointerContainer.MakeType (rc.Module, rc.Module.Compiler.BuiltinTypes.Void), rc.Module.Compiler.BuiltinTypes.Int)), BindingRestriction.DeclaredOnly) as MethodSpec;
++ if (ctor == null)
++ return false;
++
++ this.type = spanType;
++ return true;
++ }
+ }
+
+ //
+@@ -13093,6 +13157,12 @@ namespace Mono.CSharp
+ expr.Emit (ec);
+ }
+
++ public override Expression CreateExpressionTree (ResolveContext rc)
++ {
++ rc.Report.Error (8153, Location, "An expression tree lambda cannot contain a call to a method, property, or indexer that returns by reference");
++ return null;
++ }
++
+ public void Emit (EmitContext ec, bool leave_copy)
+ {
+ Emit (ec);
+@@ -13133,6 +13203,11 @@ namespace Mono.CSharp
+
+ public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
+ {
++ if (expr.ContainsEmitWithAwait ()) {
++ rc.Report.Error (8178, loc, "`await' cannot be used in an expression containing a call to `{0}' because it returns by reference",
++ expr.GetSignatureForError ());
++ }
++
+ return DoResolve (rc);
+ }
+
+@@ -13149,4 +13224,98 @@ namespace Mono.CSharp
+ return visitor.Visit (this);
+ }
+ }
++
++ class DefaultLiteralExpression : Expression
++ {
++ public DefaultLiteralExpression (Location loc)
++ {
++ this.loc = loc;
++ }
++
++ public override Expression CreateExpressionTree (ResolveContext ec)
++ {
++ throw new NotImplementedException ();
++ }
++
++ protected override Expression DoResolve (ResolveContext rc)
++ {
++ type = InternalType.DefaultType;
++ eclass = ExprClass.Value;
++ return this;
++ }
++
++ public override void Emit (EmitContext ec)
++ {
++ throw new NotSupportedException ();
++ }
++ }
++
++ class Discard : Expression, IAssignMethod, IMemoryLocation
++ {
++ public Discard (Location loc)
++ {
++ this.loc = loc;
++ }
++
++ public override Expression CreateExpressionTree (ResolveContext rc)
++ {
++ rc.Report.Error (8207, loc, "An expression tree cannot contain a discard");
++ return null;
++ }
++
++ protected override Expression DoResolve (ResolveContext rc)
++ {
++ type = InternalType.Discard;
++ eclass = ExprClass.Variable;
++ return this;
++ }
++
++ public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
++ {
++ if (right_side.Type == InternalType.DefaultType) {
++ rc.Report.Error (8183, loc, "Cannot infer the type of implicitly-typed discard");
++ type = InternalType.ErrorType;
++ return this;
++ }
++
++ if (right_side.Type.Kind == MemberKind.Void) {
++ rc.Report.Error (8209, loc, "Cannot assign void to a discard");
++ type = InternalType.ErrorType;
++ return this;
++ }
++
++ if (right_side != EmptyExpression.OutAccess) {
++ type = right_side.Type;
++ }
++
++ return this;
++ }
++
++ public override void Emit (EmitContext ec)
++ {
++ throw new NotImplementedException ();
++ }
++
++ public void Emit (EmitContext ec, bool leave_copy)
++ {
++ throw new NotImplementedException ();
++ }
++
++ public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
++ {
++ if (leave_copy)
++ source.Emit (ec);
++ else
++ source.EmitSideEffect (ec);
++ }
++
++ public void AddressOf (EmitContext ec, AddressOp mode)
++ {
++ var temp = ec.GetTemporaryLocal (type);
++ ec.Emit (OpCodes.Ldloca, temp);
++
++ // TODO: Should free it on next statement but don't have mechanism for that yet
++ // ec.FreeTemporaryLocal (temp, type);
++ }
++ }
+ }
+diff --git a/mcs/mcs/generic.cs b/mcs/mcs/generic.cs
+index 625cd0c773f..ec2965df63b 100644
+--- a/mcs/mcs/generic.cs
++++ b/mcs/mcs/generic.cs
+@@ -693,6 +693,11 @@ namespace Mono.CSharp {
+ GetSignatureForError (), mc.GetSignatureForError (), input_variance, gtype_variance, parameters);
+ }
+
++ public TypeSpec GetAsyncMethodBuilder ()
++ {
++ return null;
++ }
++
+ public TypeSpec GetAttributeCoClass ()
+ {
+ return null;
+@@ -2292,7 +2297,7 @@ namespace Mono.CSharp {
+ ok = false;
+ }
+
+- if (te.IsPointer || te.IsSpecialRuntimeType) {
++ if (te.IsPointer || te.IsSpecialRuntimeType || te.IsByRefLike) {
+ ec.Module.Compiler.Report.Error (306, args[i].Location,
+ "The type `{0}' may not be used as a type argument",
+ te.GetSignatureForError ());
+@@ -3102,7 +3107,7 @@ namespace Mono.CSharp {
+ //
+ // Some types cannot be used as type arguments
+ //
+- if ((bound.Type.Kind == MemberKind.Void && !voidAllowed) || bound.Type.IsPointer || bound.Type.IsSpecialRuntimeType ||
++ if ((bound.Type.Kind == MemberKind.Void && !voidAllowed) || bound.Type.IsPointer || bound.Type.IsSpecialRuntimeType || bound.Type.IsByRefLike ||
+ bound.Type == InternalType.MethodGroup || bound.Type == InternalType.AnonymousMethod || bound.Type == InternalType.VarOutType ||
+ bound.Type == InternalType.ThrowExpr)
+ return;
+@@ -3110,6 +3115,9 @@ namespace Mono.CSharp {
+ if (bound.Type.IsTupleType && TupleLiteral.ContainsNoTypeElement (bound.Type))
+ return;
+
++ if (bound.Type == InternalType.DefaultType)
++ return;
++
+ var a = bounds [index];
+ if (a == null) {
+ a = new List<BoundInfo> (2);
+diff --git a/mcs/mcs/import.cs b/mcs/mcs/import.cs
+index 1cddf7c01f4..f7c4fd74b08 100644
+--- a/mcs/mcs/import.cs
++++ b/mcs/mcs/import.cs
+@@ -975,6 +975,10 @@ namespace Mono.CSharp
+ mod |= Modifiers.READONLY;
+ }
+
++ if (HasAttribute (CustomAttributeData.GetCustomAttributes (type), "IsByRefLikeAttribute", CompilerServicesNamespace)) {
++ mod |= Modifiers.REF;
++ }
++
+ break;
+ }
+ }
+@@ -1401,6 +1405,7 @@ namespace Mono.CSharp
+ public string DefaultIndexerName;
+ public bool? CLSAttributeValue;
+ public TypeSpec CoClass;
++ public TypeSpec AsyncMethodBuilder;
+
+ static bool HasMissingType (ConstructorInfo ctor)
+ {
+@@ -1522,6 +1527,20 @@ namespace Mono.CSharp
+ bag.CoClass = importer.ImportType ((MetaType) a.ConstructorArguments[0].Value);
+ continue;
+ }
++
++ if (name == "AsyncMethodBuilderAttribute") {
++ if (dt.Namespace != "System.Runtime.CompilerServices")
++ continue;
++
++ if (HasMissingType (a.Constructor))
++ continue;
++
++ if (bag == null)
++ bag = new AttributesBag ();
++
++ bag.AsyncMethodBuilder = importer.ImportType ((MetaType)a.ConstructorArguments [0].Value);
++ continue;
++ }
+ }
+ }
+
+@@ -2129,6 +2148,14 @@ namespace Mono.CSharp
+ }
+ }
+
++ public TypeSpec GetAsyncMethodBuilder ()
++ {
++ if (cattrs == null)
++ ReadAttributes ();
++
++ return cattrs.AsyncMethodBuilder;
++ }
++
+ public TypeSpec GetAttributeCoClass ()
+ {
+ if (cattrs == null)
+@@ -2445,6 +2472,11 @@ namespace Mono.CSharp
+
+ #endregion
+
++ public TypeSpec GetAsyncMethodBuilder ()
++ {
++ return null;
++ }
++
+ public TypeSpec GetAttributeCoClass ()
+ {
+ return null;
+diff --git a/mcs/mcs/membercache.cs b/mcs/mcs/membercache.cs
+index eebf71b844b..ca05d2d7afc 100644
+--- a/mcs/mcs/membercache.cs
++++ b/mcs/mcs/membercache.cs
+@@ -309,7 +309,6 @@ namespace Mono.CSharp {
+ //
+ if (!BuiltinTypeSpec.IsPrimitiveType (dt) || dt.BuiltinType == BuiltinTypeSpec.Type.Char) {
+ switch (dt.BuiltinType) {
+- case BuiltinTypeSpec.Type.String:
+ case BuiltinTypeSpec.Type.Delegate:
+ case BuiltinTypeSpec.Type.MulticastDelegate:
+ break;
+@@ -317,6 +316,9 @@ namespace Mono.CSharp {
+ if (name == Operator.GetMetadataName (Operator.OpType.Implicit) || name == Operator.GetMetadataName (Operator.OpType.Explicit)) {
+ state |= StateFlags.HasConversionOperator;
+ } else {
++ if (dt.BuiltinType == BuiltinTypeSpec.Type.String)
++ break;
++
+ state |= StateFlags.HasUserOperator;
+ }
+
+diff --git a/mcs/mcs/method.cs b/mcs/mcs/method.cs
+index ccd4898e91c..1fca10dd6d0 100644
+--- a/mcs/mcs/method.cs
++++ b/mcs/mcs/method.cs
+@@ -701,6 +701,10 @@ namespace Mono.CSharp {
+ if (MemberType.IsStatic) {
+ Error_StaticReturnType ();
+ }
++
++ if (MemberType.IsSpecialRuntimeType && Compiler.Settings.StdLib) {
++ Error_ReturnTypeCantBeRefAny (Location, ReturnType, Report);
++ }
+ }
+
+ public override void Emit ()
+@@ -716,6 +720,8 @@ namespace Mono.CSharp {
+ Module.PredefinedAttributes.Dynamic.EmitAttribute (CreateReturnBuilder ().Builder);
+ } else if (ReturnType.HasDynamicElement) {
+ Module.PredefinedAttributes.Dynamic.EmitAttribute (CreateReturnBuilder ().Builder, ReturnType, Location);
++ } else if (ReturnType is ReadOnlyReferenceContainer) {
++ Module.PredefinedAttributes.IsReadOnly.EmitAttribute (CreateReturnBuilder ().Builder);
+ }
+
+ if (ReturnType.HasNamedTupleElement) {
+@@ -764,6 +770,11 @@ namespace Mono.CSharp {
+ GetSignatureForError ());
+ }
+
++ public static void Error_ReturnTypeCantBeRefAny (Location loc, TypeSpec t, Report Report)
++ {
++ Report.Error (1599, loc, "The return type of `{0}' is not allowed", t.GetSignatureForError ());
++ }
++
+ public bool IsPartialDefinition {
+ get {
+ return (ModFlags & Modifiers.PARTIAL) != 0 && Block == null;
+@@ -1231,11 +1242,6 @@ namespace Mono.CSharp {
+ "Introducing `Finalize' method can interfere with destructor invocation. Did you intend to declare a destructor?");
+ }
+
+- if (Compiler.Settings.StdLib && ReturnType.IsSpecialRuntimeType) {
+- Error1599 (Location, ReturnType, Report);
+- return false;
+- }
+-
+ if (CurrentTypeParameters == null) {
+ if (base_method != null && !IsExplicitImpl) {
+ if (parameters.Count == 1 && ParameterTypes[0].BuiltinType == BuiltinTypeSpec.Type.Object && MemberName.Name == "Equals")
+@@ -1261,8 +1267,9 @@ namespace Mono.CSharp {
+ if ((ModFlags & Modifiers.ASYNC) != 0) {
+ if (ReturnType.Kind != MemberKind.Void &&
+ ReturnType != Module.PredefinedTypes.Task.TypeSpec &&
+- !ReturnType.IsGenericTask) {
+- Report.Error (1983, Location, "The return type of an async method must be void, Task, or Task<T>");
++ !ReturnType.IsGenericTask &&
++ !ReturnType.IsCustomTaskType ()) {
++ Report.Error (1983, Location, "The return type of an async method must be void or task type");
+ }
+
+ block = (ToplevelBlock) block.ConvertToAsyncTask (this, Parent.PartialContainer, parameters, ReturnType, null, Location);
+@@ -1396,11 +1403,6 @@ namespace Mono.CSharp {
+ return base.EnableOverloadChecks (overload);
+ }
+
+- public static void Error1599 (Location loc, TypeSpec t, Report Report)
+- {
+- Report.Error (1599, loc, "Method or delegate cannot return type `{0}'", t.GetSignatureForError ());
+- }
+-
+ protected override bool ResolveMemberType ()
+ {
+ if (CurrentTypeParameters != null) {
+@@ -2467,6 +2469,8 @@ namespace Mono.CSharp {
+ Module.PredefinedAttributes.Dynamic.EmitAttribute (CreateReturnBuilder ().Builder);
+ } else if (ReturnType.HasDynamicElement) {
+ Module.PredefinedAttributes.Dynamic.EmitAttribute (CreateReturnBuilder ().Builder, ReturnType, Location);
++ } else if (ReturnType is ReadOnlyReferenceContainer) {
++ Module.PredefinedAttributes.IsReadOnly.EmitAttribute (CreateReturnBuilder ().Builder);
+ }
+
+ if (ReturnType.HasNamedTupleElement) {
+diff --git a/mcs/mcs/modifiers.cs b/mcs/mcs/modifiers.cs
+index bfae5985a03..926ab5d1848 100644
+--- a/mcs/mcs/modifiers.cs
++++ b/mcs/mcs/modifiers.cs
+@@ -53,6 +53,7 @@ namespace Mono.CSharp
+ DEBUGGER_HIDDEN = 0x400000,
+ DEBUGGER_STEP_THROUGH = 0x800000,
+ AutoProperty = 0x1000000,
++ REF = 0x2000000,
+
+ AccessibilityMask = PUBLIC | PROTECTED | INTERNAL | PRIVATE,
+ AllowedExplicitImplFlags = UNSAFE | EXTERN,
+diff --git a/mcs/mcs/module.cs b/mcs/mcs/module.cs
+index 00afac6c604..2293d825b36 100644
+--- a/mcs/mcs/module.cs
++++ b/mcs/mcs/module.cs
+@@ -265,6 +265,7 @@ namespace Mono.CSharp
+ readonly Dictionary<ArrayContainer.TypeRankPair, ArrayContainer> array_types;
+ readonly Dictionary<TypeSpec, PointerContainer> pointer_types;
+ readonly Dictionary<TypeSpec, ReferenceContainer> reference_types;
++ readonly Dictionary<TypeSpec, ReadOnlyReferenceContainer> readonly_reference_types;
+ readonly Dictionary<TypeSpec, MethodSpec> attrs_cache;
+ readonly Dictionary<TypeSpec, AwaiterDefinition> awaiters;
+ readonly Dictionary<TypeSpec, TypeInfo> type_info_cache;
+@@ -301,6 +302,7 @@ namespace Mono.CSharp
+ array_types = new Dictionary<ArrayContainer.TypeRankPair, ArrayContainer> ();
+ pointer_types = new Dictionary<TypeSpec, PointerContainer> ();
+ reference_types = new Dictionary<TypeSpec, ReferenceContainer> ();
++ readonly_reference_types = new Dictionary<TypeSpec, ReadOnlyReferenceContainer> ();
+ attrs_cache = new Dictionary<TypeSpec, MethodSpec> ();
+ awaiters = new Dictionary<TypeSpec, AwaiterDefinition> ();
+ type_info_cache = new Dictionary<TypeSpec, TypeInfo> ();
+@@ -427,6 +429,12 @@ namespace Mono.CSharp
+ }
+ }
+
++ internal Dictionary<TypeSpec, ReadOnlyReferenceContainer> ReadonlyReferenceTypesCache {
++ get {
++ return readonly_reference_types;
++ }
++ }
++
+ internal Dictionary<TypeSpec, TypeInfo> TypeInfoCache {
+ get {
+ return type_info_cache;
+diff --git a/mcs/mcs/parameter.cs b/mcs/mcs/parameter.cs
+index 2bd2a498a91..cc10eee162b 100644
+--- a/mcs/mcs/parameter.cs
++++ b/mcs/mcs/parameter.cs
+@@ -1447,7 +1447,7 @@ namespace Mono.CSharp {
+
+ expr = Child;
+
+- if (!(expr is Constant || expr is DefaultValueExpression || (expr is New && ((New) expr).IsGeneratedStructConstructor))) {
++ if (!(expr is Constant || expr is DefaultValueExpression || expr is DefaultLiteralExpression || (expr is New && ((New) expr).IsGeneratedStructConstructor))) {
+ if (!(expr is ErrorExpression)) {
+ rc.Report.Error (1736, Location,
+ "The expression being assigned to optional parameter `{0}' must be a constant or default value",
+diff --git a/mcs/mcs/statement.cs b/mcs/mcs/statement.cs
+index 58ba2795e4b..9c51128548f 100644
+--- a/mcs/mcs/statement.cs
++++ b/mcs/mcs/statement.cs
+@@ -1160,7 +1160,8 @@ namespace Mono.CSharp {
+ //
+ if (ec.CurrentAnonymousMethod is AsyncInitializer) {
+ var storey = (AsyncTaskStorey) ec.CurrentAnonymousMethod.Storey;
+- if (storey.ReturnType == ec.Module.PredefinedTypes.Task.TypeSpec) {
++ var s_return_type = storey.ReturnType;
++ if (s_return_type == ec.Module.PredefinedTypes.Task.TypeSpec) {
+ //
+ // Extra trick not to emit ret/leave inside awaiter body
+ //
+@@ -1168,8 +1169,8 @@ namespace Mono.CSharp {
+ return true;
+ }
+
+- if (storey.ReturnType.IsGenericTask)
+- block_return_type = storey.ReturnType.TypeArguments[0];
++ if (s_return_type.IsGenericTask || (s_return_type.Arity == 1 && s_return_type.IsCustomTaskType ()))
++ block_return_type = s_return_type.TypeArguments[0];
+ }
+
+ if (ec.CurrentIterator != null) {
+@@ -1220,7 +1221,7 @@ namespace Mono.CSharp {
+ return false;
+ }
+
+- if (!async_type.IsGenericTask) {
++ if (!async_type.IsGeneric) {
+ if (this is ContextualReturn)
+ return true;
+
+@@ -2368,7 +2369,12 @@ namespace Mono.CSharp {
+ if (initializer == null)
+ return null;
+
+- var c = initializer as Constant;
++ Constant c;
++ if (initializer.Type == InternalType.DefaultType)
++ c = New.Constantify (li.Type, initializer.Location);
++ else
++ c = initializer as Constant;
++
+ if (c == null) {
+ initializer.Error_ExpressionMustBeConstant (bc, initializer.Location, li.Name);
+ return null;
+@@ -2407,14 +2413,14 @@ namespace Mono.CSharp {
+ AddressTaken = 1 << 2,
+ CompilerGenerated = 1 << 3,
+ Constant = 1 << 4,
+- ForeachVariable = 1 << 5,
+- FixedVariable = 1 << 6,
+- UsingVariable = 1 << 7,
++ ForeachVariable = 1 << 5 | ReadonlyMask,
++ FixedVariable = 1 << 6 | ReadonlyMask,
++ UsingVariable = 1 << 7 | ReadonlyMask,
+ IsLocked = 1 << 8,
+ SymbolFileHidden = 1 << 9,
+ ByRef = 1 << 10,
+
+- ReadonlyMask = ForeachVariable | FixedVariable | UsingVariable
++ ReadonlyMask = 1 << 20
+ }
+
+ TypeSpec type;
+@@ -2534,7 +2540,7 @@ namespace Mono.CSharp {
+
+ public bool IsFixed {
+ get {
+- return (flags & Flags.FixedVariable) != 0;
++ return (flags & Flags.FixedVariable) == Flags.FixedVariable;
+ }
+ set {
+ flags = value ? flags | Flags.FixedVariable : flags & ~Flags.FixedVariable;
+@@ -2672,7 +2678,7 @@ namespace Mono.CSharp {
+
+ public string GetReadOnlyContext ()
+ {
+- switch (flags & Flags.ReadonlyMask) {
++ switch (flags & (Flags.ForeachVariable | Flags.FixedVariable | Flags.UsingVariable)) {
+ case Flags.FixedVariable:
+ return "fixed variable";
+ case Flags.ForeachVariable:
+@@ -8191,7 +8197,9 @@ namespace Mono.CSharp {
+ }
+
+ if (iface_candidate == null) {
+- if (expr.Type != InternalType.ErrorType) {
++ if (expr.Type == InternalType.DefaultType) {
++ rc.Report.Error (8312, loc, "Use of default literal is not valid in this context");
++ } else if (expr.Type != InternalType.ErrorType) {
+ rc.Report.Error (1579, loc,
+ "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `{1}' or is inaccessible",
+ expr.Type.GetSignatureForError (), "GetEnumerator");
+diff --git a/mcs/mcs/tuples.cs b/mcs/mcs/tuples.cs
+index bb7faf734df..901efdc9541 100644
+--- a/mcs/mcs/tuples.cs
++++ b/mcs/mcs/tuples.cs
+@@ -432,7 +432,7 @@ namespace Mono.CSharp
+ {
+ Expression source;
+ List<Expression> targetExprs;
+- List<LocalVariable> variablesToInfer;
++ List<BlockVariable> variables;
+ Expression instance;
+
+ public TupleDeconstruct (List<Expression> targetExprs, Expression source, Location loc)
+@@ -442,10 +442,11 @@ namespace Mono.CSharp
+ this.loc = loc;
+ }
+
+- public TupleDeconstruct (List<Expression> targetExprs, List<LocalVariable> variables, Expression source, Location loc)
+- : this (targetExprs, source, loc)
++ public TupleDeconstruct (List<BlockVariable> variables, Expression source, Location loc)
+ {
+- this.variablesToInfer = variables;
++ this.source = source;
++ this.variables = variables;
++ this.loc = loc;
+ }
+
+ public override Expression CreateExpressionTree (ResolveContext ec)
+@@ -469,9 +470,18 @@ namespace Mono.CSharp
+ var src_type = src.Type;
+
+ if (src_type.IsTupleType) {
+- if (src_type.Arity != targetExprs.Count) {
++ int target_count;
++
++ if (targetExprs == null) {
++ target_count = variables.Count;
++ targetExprs = new List<Expression> (target_count);
++ } else {
++ target_count = targetExprs.Count;
++ }
++
++ if (src_type.Arity != target_count) {
+ rc.Report.Error (8132, loc, "Cannot deconstruct a tuple of `{0}' elements into `{1}' variables",
+- src_type.Arity.ToString (), targetExprs.Count.ToString ());
++ src_type.Arity.ToString (CultureInfo.InvariantCulture), target_count.ToString (CultureInfo.InvariantCulture));
+ return null;
+ }
+
+@@ -482,27 +492,44 @@ namespace Mono.CSharp
+ instance = expr_variable.CreateReferenceExpression (rc, loc);
+ }
+
+- for (int i = 0; i < targetExprs.Count; ++i) {
++ for (int i = 0; i < target_count; ++i) {
+ var tle = src_type.TypeArguments [i];
+
+- var lv = variablesToInfer? [i];
+- if (lv != null) {
+- if (InternalType.HasNoType (tle)) {
+- rc.Report.Error (8130, Location, "Cannot infer the type of implicitly-typed deconstruction variable `{0}'", lv.Name);
+- lv.Type = InternalType.ErrorType;
++ if (variables != null) {
++ var variable = variables [i].Variable;
++
++ if (variable.Type == InternalType.Discard) {
++ variables [i] = null;
++ targetExprs.Add (EmptyExpressionStatement.Instance);
+ continue;
+ }
+
+- lv.Type = tle;
+- lv.PrepareAssignmentAnalysis ((BlockContext) rc);
+- }
++ var variable_type = variables [i].TypeExpression;
++
++ targetExprs.Add (new LocalVariableReference (variable, variable.Location));
++
++ if (variable_type is VarExpr) {
++ if (InternalType.HasNoType (tle)) {
++ rc.Report.Error (8130, Location, "Cannot infer the type of implicitly-typed deconstruction variable `{0}'", variable.Name);
++ tle = InternalType.ErrorType;
++ }
+
++ variable.Type = tle;
++ } else {
++ variable.Type = variable_type.ResolveAsType (rc);
++ }
++
++ variable.PrepareAssignmentAnalysis ((BlockContext)rc);
++ }
+
+ var element_src = tupleLiteral == null ? new MemberAccess (instance, NamedTupleSpec.GetElementPropertyName (i)) : tupleLiteral.Elements [i].Expr;
+ targetExprs [i] = new SimpleAssign (targetExprs [i], element_src).Resolve (rc);
+ }
+
+ eclass = ExprClass.Value;
++
++ // TODO: The type is same only if there is no target element conversion
++ // var res = (/*byte*/ b, /*short*/ s) = (2, 4);
+ type = src.Type;
+ return this;
+ }
+@@ -527,11 +554,24 @@ namespace Mono.CSharp
+
+ public override void Emit (EmitContext ec)
+ {
+- throw new NotImplementedException ();
++ if (instance != null)
++ ((ExpressionStatement)source).EmitStatement (ec);
++
++ foreach (ExpressionStatement expr in targetExprs)
++ expr.Emit (ec);
++
++ var ctor = MemberCache.FindMember (type, MemberFilter.Constructor (null), BindingRestriction.DeclaredOnly | BindingRestriction.InstanceOnly) as MethodSpec;
++ ec.Emit (OpCodes.Newobj, ctor);
+ }
+
+ public override void EmitStatement (EmitContext ec)
+ {
++ if (variables != null) {
++ foreach (var lv in variables) {
++ lv?.Variable.CreateBuilder (ec);
++ }
++ }
++
+ if (instance != null)
+ ((ExpressionStatement) source).EmitStatement (ec);
+
+@@ -549,9 +589,6 @@ namespace Mono.CSharp
+ if (leave_copy)
+ throw new NotImplementedException ();
+
+- foreach (var lv in variablesToInfer)
+- lv.CreateBuilder (ec);
+-
+ EmitStatement (ec);
+ }
+
+@@ -563,11 +600,11 @@ namespace Mono.CSharp
+
+ public void SetGeneratedFieldAssigned (FlowAnalysisContext fc)
+ {
+- if (variablesToInfer == null)
++ if (variables == null)
+ return;
+
+- foreach (var lv in variablesToInfer)
+- fc.SetVariableAssigned (lv.VariableInfo);
++ foreach (var lv in variables)
++ fc.SetVariableAssigned (lv.Variable.VariableInfo);
+ }
+ }
+ }
+\ No newline at end of file
+diff --git a/mcs/mcs/typemanager.cs b/mcs/mcs/typemanager.cs
+index b6aff14e1c0..7a16cda2774 100644
+--- a/mcs/mcs/typemanager.cs
++++ b/mcs/mcs/typemanager.cs
+@@ -242,6 +242,7 @@ namespace Mono.CSharp
+
+ // C# 7.0
+ public readonly PredefinedType[] Tuples;
++ public readonly PredefinedType SpanGeneric;
+
+ public PredefinedTypes (ModuleContainer module)
+ {
+@@ -301,6 +302,8 @@ namespace Mono.CSharp
+ FormattableString = new PredefinedType (module, MemberKind.Class, "System", "FormattableString");
+ FormattableStringFactory = new PredefinedType (module, MemberKind.Class, "System.Runtime.CompilerServices", "FormattableStringFactory");
+
++ SpanGeneric = new PredefinedType (module, MemberKind.Struct, "System", "Span", 1);
++
+ //
+ // Define types which are used for comparison. It does not matter
+ // if they don't exist as no error report is needed
+@@ -348,6 +351,8 @@ namespace Mono.CSharp
+ if (pt.Define ())
+ pt.TypeSpec.IsTupleType = true;
+ }
++
++ SpanGeneric.Define ();
+ }
+ }
+
+@@ -430,6 +435,7 @@ namespace Mono.CSharp
+ ArrayEmpty = new PredefinedMember<MethodSpec> (module, types.Array,
+ MemberFilter.Method ("Empty", 1, ParametersCompiled.EmptyReadOnlyParameters, null));
+
++ // TODO: Must me static
+ AsyncTaskMethodBuilderCreate = new PredefinedMember<MethodSpec> (module, types.AsyncTaskMethodBuilder,
+ MemberFilter.Method ("Create", 0, ParametersCompiled.EmptyReadOnlyParameters, types.AsyncTaskMethodBuilder.TypeSpec));
+
+@@ -485,6 +491,7 @@ namespace Mono.CSharp
+ AsyncTaskMethodBuilderTask = new PredefinedMember<PropertySpec> (module, types.AsyncTaskMethodBuilder,
+ MemberFilter.Property ("Task", null));
+
++ // TODO: Must me static
+ AsyncTaskMethodBuilderGenericCreate = new PredefinedMember<MethodSpec> (module, types.AsyncTaskMethodBuilderGeneric,
+ MemberFilter.Method ("Create", 0, ParametersCompiled.EmptyReadOnlyParameters, types.AsyncVoidMethodBuilder.TypeSpec));
+
+@@ -542,6 +549,7 @@ namespace Mono.CSharp
+ AsyncTaskMethodBuilderGenericTask = new PredefinedMember<PropertySpec> (module, types.AsyncTaskMethodBuilderGeneric,
+ MemberFilter.Property ("Task", null));
+
++ // TODO: Must me static
+ AsyncVoidMethodBuilderCreate = new PredefinedMember<MethodSpec> (module, types.AsyncVoidMethodBuilder,
+ MemberFilter.Method ("Create", 0, ParametersCompiled.EmptyReadOnlyParameters, types.AsyncVoidMethodBuilder.TypeSpec));
+
+@@ -1006,9 +1014,6 @@ namespace Mono.CSharp
+
+ public T Resolve (Location loc)
+ {
+- if (member != null)
+- return member;
+-
+ if (Get () != null)
+ return member;
+
+diff --git a/mcs/mcs/typespec.cs b/mcs/mcs/typespec.cs
+index d14e1ead3e3..a58a0fe5178 100644
+--- a/mcs/mcs/typespec.cs
++++ b/mcs/mcs/typespec.cs
+@@ -225,6 +225,8 @@ namespace Mono.CSharp
+ }
+ }
+
++ public bool IsByRefLike => (modifiers & Modifiers.REF) != 0;
++
+ //
+ // Returns true for instances of System.Threading.Tasks.Task<T>
+ //
+@@ -1452,6 +1454,7 @@ namespace Mono.CSharp
+ int TypeParametersCount { get; }
+ TypeParameterSpec[] TypeParameters { get; }
+
++ TypeSpec GetAsyncMethodBuilder ();
+ TypeSpec GetAttributeCoClass ();
+ string GetAttributeDefaultMember ();
+ AttributeUsageAttribute GetAttributeUsage (PredefinedAttribute pa);
+@@ -1461,6 +1464,29 @@ namespace Mono.CSharp
+
+ class InternalType : TypeSpec, ITypeDefinition
+ {
++ sealed class InternalTypeAssembly : IAssemblyDefinition
++ {
++ public static readonly InternalTypeAssembly Instance = new InternalTypeAssembly ();
++
++ public string FullName => throw new NotImplementedException ();
++
++ public bool IsCLSCompliant => false;
++
++ public bool IsMissing => false;
++
++ public string Name => throw new NotImplementedException ();
++
++ public byte [] GetPublicKeyToken ()
++ {
++ throw new NotImplementedException ();
++ }
++
++ public bool IsFriendAssemblyTo (IAssemblyDefinition assembly)
++ {
++ return false;
++ }
++ }
++
+ public static readonly InternalType AnonymousMethod = new InternalType ("anonymous method");
+ public static readonly InternalType Arglist = new InternalType ("__arglist");
+ public static readonly InternalType MethodGroup = new InternalType ("method group");
+@@ -1470,6 +1496,8 @@ namespace Mono.CSharp
+ public static readonly InternalType ErrorType = new InternalType ("<error>");
+ public static readonly InternalType VarOutType = new InternalType ("var out");
+ public static readonly InternalType ThrowExpr = new InternalType ("throw expression");
++ public static readonly InternalType DefaultType = new InternalType ("default");
++ public static readonly InternalType Discard = new InternalType ("discard");
+
+ readonly string name;
+
+@@ -1494,7 +1522,7 @@ namespace Mono.CSharp
+
+ IAssemblyDefinition ITypeDefinition.DeclaringAssembly {
+ get {
+- throw new NotImplementedException ();
++ return InternalTypeAssembly.Instance;
+ }
+ }
+
+@@ -1561,6 +1589,11 @@ namespace Mono.CSharp
+
+ #region ITypeDefinition Members
+
++ TypeSpec ITypeDefinition.GetAsyncMethodBuilder ()
++ {
++ return null;
++ }
++
+ TypeSpec ITypeDefinition.GetAttributeCoClass ()
+ {
+ return null;
+@@ -1614,7 +1647,7 @@ namespace Mono.CSharp
+
+ public static bool HasNoType (TypeSpec type)
+ {
+- return type == AnonymousMethod || type == MethodGroup || type == NullLiteral || type == ThrowExpr;
++ return type == AnonymousMethod || type == MethodGroup || type == NullLiteral || type == ThrowExpr || type == DefaultType;
+ }
+ }
+
+@@ -1749,6 +1782,11 @@ namespace Mono.CSharp
+ }
+ }
+
++ public TypeSpec GetAsyncMethodBuilder ()
++ {
++ return null;
++ }
++
+ public TypeSpec GetAttributeCoClass ()
+ {
+ return Element.MemberDefinition.GetAttributeCoClass ();
+@@ -1996,9 +2034,10 @@ namespace Mono.CSharp
+ [System.Diagnostics.DebuggerDisplay("{DisplayDebugInfo()}")]
+ class ReferenceContainer : ElementTypeSpec
+ {
+- ReferenceContainer (TypeSpec element)
++ protected ReferenceContainer (TypeSpec element)
+ : base (MemberKind.ByRef, element, null)
+ {
++ cache = null;
+ }
+
+ public override IList<TypeSpec> Interfaces {
+@@ -2039,6 +2078,39 @@ namespace Mono.CSharp
+
+ return pc;
+ }
++
++ protected override void InitializeMemberCache(bool onlyTypes)
++ {
++ cache = Element.MemberCache;
++ }
++ }
++
++ [System.Diagnostics.DebuggerDisplay ("{DisplayDebugInfo()}")]
++ class ReadOnlyReferenceContainer : ReferenceContainer
++ {
++ public ReadOnlyReferenceContainer (TypeSpec element)
++ : base (element)
++ {
++ }
++
++ string DisplayDebugInfo ()
++ {
++ return "ref readonly " + GetSignatureForError ();
++ }
++
++ public new static ReferenceContainer MakeType (ModuleContainer module, TypeSpec element)
++ {
++ if (element.Kind == MemberKind.ByRef)
++ throw new ArgumentException ();
++
++ ReadOnlyReferenceContainer pc;
++ if (!module.ReadonlyReferenceTypesCache.TryGetValue (element, out pc)) {
++ pc = new ReadOnlyReferenceContainer (element);
++ module.ReadonlyReferenceTypesCache.Add (element, pc);
++ }
++
++ return pc;
++ }
+ }
+
+ class PointerContainer : ElementTypeSpec
+diff --git a/mcs/tests/gtest-409.cs b/mcs/tests/gtest-409.cs
+index 8db59d7e48d..606ae3685d1 100644
+--- a/mcs/tests/gtest-409.cs
++++ b/mcs/tests/gtest-409.cs
+@@ -1,3 +1,4 @@
++// Compiler options: -langversion:latest
+ using System;
+
+ //
+@@ -175,6 +176,11 @@ public class ConditionalParsing
+ var x = args ?.2f : -.2f;
+ }
+
++ void Test_23 (string args)
++ {
++ var x = args == null ? default : 1;
++ }
++
+ static void Helper<T> (T arg)
+ {
+ }
+diff --git a/mcs/tests/test-948.cs b/mcs/tests/test-948.cs
+new file mode 100644
+index 00000000000..34b3ab9a0c4
+--- /dev/null
++++ b/mcs/tests/test-948.cs
+@@ -0,0 +1,16 @@
++// Compiler options: -langversion:7.2 -unsafe
++
++using System;
++
++class X
++{
++ public static void Main ()
++ {
++ Span<int> stackSpan = stackalloc int[100];
++ }
++
++ unsafe void Foo ()
++ {
++
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-async-94.cs b/mcs/tests/test-async-94.cs
+new file mode 100644
+index 00000000000..ce9a30409bb
+--- /dev/null
++++ b/mcs/tests/test-async-94.cs
+@@ -0,0 +1,127 @@
++using System;
++using System.Threading.Tasks;
++using System.Runtime.CompilerServices;
++
++[AsyncMethodBuilder (typeof(MyTaskMethodBuilder<>))]
++class MyTask<T>
++{
++}
++
++[AsyncMethodBuilder (typeof(MyTaskMethodBuilder))]
++class MyTask
++{
++}
++
++class MyTaskMethodBuilder
++{
++ public static MyTaskMethodBuilder Create()
++ {
++ return null;
++ }
++
++ public MyTask Task {
++ get {
++ return null;
++ }
++ }
++
++ public void SetException (Exception exception)
++ {
++
++ }
++
++ public void SetResult ()
++ {
++
++ }
++
++ public void AwaitOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine
++ {
++
++ }
++
++ public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine
++ {
++
++ }
++
++ public void Start<TStateMachine> (ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine
++ {
++
++ }
++
++ public void SetStateMachine (IAsyncStateMachine stateMachine)
++ {
++
++ }
++}
++
++class MyTaskMethodBuilder<T>
++{
++ public static MyTaskMethodBuilder<T> Create()
++ {
++ return null;
++ }
++
++ public MyTask<T> Task {
++ get {
++ return null;
++ }
++ }
++
++ public void SetException (Exception exception)
++ {
++
++ }
++
++ public void SetResult (T result)
++ {
++
++ }
++
++ public void AwaitOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : INotifyCompletion where TStateMachine : IAsyncStateMachine
++ {
++
++ }
++
++ public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine) where TAwaiter : ICriticalNotifyCompletion where TStateMachine : IAsyncStateMachine
++ {
++
++ }
++
++ public void Start<TStateMachine> (ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine
++ {
++
++ }
++
++ public void SetStateMachine (IAsyncStateMachine stateMachine)
++ {
++
++ }
++}
++
++class X
++{
++ public async MyTask Test ()
++ {
++ await Task.Delay (1);
++ }
++
++ public async MyTask<int> Test2 ()
++ {
++ await Task.Delay (1);
++ return 2;
++ }
++
++ public async ValueTask<string> Test3 ()
++ {
++ await Task.Delay (1);
++ return "as";
++ }
++
++ public static void Main ()
++ {
++ var x = new X ();
++ var r1 = x.Test3 ().Result;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-default-01.cs b/mcs/tests/test-default-01.cs
+new file mode 100644
+index 00000000000..823e33c451b
+--- /dev/null
++++ b/mcs/tests/test-default-01.cs
+@@ -0,0 +1,52 @@
++// Compiler options: -langversion:latest
++
++static class X
++{
++ const int c1 = default;
++ const int c2 = default (int);
++
++ public static void Main ()
++ {
++ int a = default;
++ var b = (int) default;
++ const int c = default;
++ var d = new[] { 1, default };
++ dynamic e = default;
++ int f = checked (default);
++ (int a, int b) g = (1, default);
++ var h = 1 != default;
++ var i = default == M4 ();
++ }
++
++ static int M1 ()
++ {
++ return default;
++ }
++
++ static void M2 ()
++ {
++ try {
++ throw new System.Exception ();
++ } catch (System.Exception) when (default) {
++ }
++
++ if (default) {
++ }
++ }
++
++ static void M3 (int x = default)
++ {
++ }
++
++ static System.Func<int> M4 ()
++ {
++ return () => default;
++ }
++}
++/*
++enum E
++{
++ A = default,
++ B = default + 1
++}
++*/
+\ No newline at end of file
+diff --git a/mcs/tests/test-default-02.cs b/mcs/tests/test-default-02.cs
+new file mode 100644
+index 00000000000..0039782e5f2
+--- /dev/null
++++ b/mcs/tests/test-default-02.cs
+@@ -0,0 +1,33 @@
++// Compiler options: -langversion:latest
++
++class C
++{
++ static void Main()
++ {
++ M (default, 1);
++
++ M2 (default);
++ M2 (null);
++
++ var res = Test (default);
++ }
++
++
++ static void M<T> (T x, T y)
++ {
++ }
++
++ static void M2 (params object[] x)
++ {
++ }
++
++ static byte[] Test (S<byte> x)
++ {
++ return null;
++ }
++}
++
++struct S<T>
++{
++
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-discards-01.cs b/mcs/tests/test-discards-01.cs
+new file mode 100644
+index 00000000000..54cf29779c6
+--- /dev/null
++++ b/mcs/tests/test-discards-01.cs
+@@ -0,0 +1,36 @@
++using System;
++
++class X
++{
++ public static void Main ()
++ {
++ string s = null;
++
++ _ = 1;
++ {
++ char _ = '4';
++ }
++
++ _ = TestValue ();
++
++ _ = _ = s;
++
++ byte k1;
++ var s1 = (k1, _) = (1, s);
++
++ Func<object> l1 = () => _ = (_, _) = (1, s);
++
++ TryGetValue (out _);
++ }
++
++ static bool TryGetValue (out int arg)
++ {
++ arg = 3;
++ return true;
++ }
++
++ static int TestValue ()
++ {
++ return 4;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-named-11.cs b/mcs/tests/test-named-11.cs
+new file mode 100644
+index 00000000000..a01d2883b9c
+--- /dev/null
++++ b/mcs/tests/test-named-11.cs
+@@ -0,0 +1,13 @@
++// Compiler options: -langversion:7.2
++
++class X
++{
++ public static void Main ()
++ {
++ Test (arg: 1, "");
++ }
++
++ static void Test (int arg, string str)
++ {
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-readonly-02.cs b/mcs/tests/test-readonly-02.cs
+new file mode 100644
+index 00000000000..231b8cd8fda
+--- /dev/null
++++ b/mcs/tests/test-readonly-02.cs
+@@ -0,0 +1,27 @@
++// Compiler options: -langversion:latest
++using System;
++
++public delegate ref readonly int D (int x);
++
++class X
++{
++ public static void Main ()
++ {
++
++ }
++
++ Guid g;
++
++ ref readonly Guid TestMethod ()
++ {
++ return ref g;
++ }
++
++ ref readonly Guid TestProp {
++ get {
++ ref readonly var rg = ref g;
++ return ref rg;
++ }
++ }
++
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-readonly-03.cs b/mcs/tests/test-readonly-03.cs
+new file mode 100644
+index 00000000000..14cb958b41a
+--- /dev/null
++++ b/mcs/tests/test-readonly-03.cs
+@@ -0,0 +1,16 @@
++// Compiler options: -langversion:latest
++using System;
++
++readonly struct S
++{
++ static S shared = new S ();
++
++ public S (int arg)
++ {
++ this = shared;
++ }
++
++ public static void Main ()
++ {
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-ref-07.cs b/mcs/tests/test-ref-07.cs
+new file mode 100644
+index 00000000000..4aa16579752
+--- /dev/null
++++ b/mcs/tests/test-ref-07.cs
+@@ -0,0 +1,30 @@
++// Compiler options: -langversion:latest
++
++public readonly partial ref struct Test
++{
++ public static void Main ()
++ {
++ var m = new Test ();
++ m.Method ();
++ }
++
++ Test Method ()
++ {
++ return new Test ();
++ }
++}
++
++ref struct Second
++{
++ Test field;
++}
++
++public abstract class P
++{
++ public abstract Test Span { get; }
++}
++
++public interface II
++{
++ Test Span { get; }
++}
+diff --git a/mcs/tests/test-ref-08.cs b/mcs/tests/test-ref-08.cs
+new file mode 100644
+index 00000000000..f4ff50f4c5c
+--- /dev/null
++++ b/mcs/tests/test-ref-08.cs
+@@ -0,0 +1,101 @@
++using System;
++
++namespace ClassLibrary1
++{
++ public class C
++ {
++
++ class B
++ {
++ int v;
++ public ref int this[int index]
++ {
++ get
++ {
++ return ref v;
++ }
++ }
++ }
++
++
++ class Gen<T> where T : struct
++ {
++ T v;
++ public ref T this[int index]
++ {
++ get
++ {
++ return ref v;
++ }
++ }
++ }
++
++ struct Val
++ {
++ }
++
++ class BB
++ {
++ Val v;
++ public ref Val this[int index]
++ {
++ get
++ {
++ return ref v;
++ }
++ }
++ }
++
++ void MM ()
++ {
++ var bbb = new BB();
++ Val v1 = bbb[0];
++ bbb[1] = v1;
++
++ ref Val v2 = ref bbb[2];
++ bbb[2] = v2;
++ }
++
++ static int[] a = new int[1];
++ public static void Main()
++ {
++ var bb = new B();
++ int b = 1;
++ bb[0] = b;
++ a[0] = Add2(ref b, 2);
++
++ var bbb = new BB();
++ bbb[0] = new Val();
++
++ var v = new Val();
++ bbb[1] = v;
++
++ var v2 = bbb[2];
++
++ bbb[3] = v2;
++
++
++ bbb[3] = bbb[2];
++
++
++
++ var ggg = new Gen<Val>();
++ ggg[0] = new Val();
++
++ var g = new Val();
++ ggg[1] = v;
++
++ var g2 = ggg[2];
++
++ ggg[3] = v2;
++
++
++ ggg[3] = ggg[2];
++ }
++
++ public static ref int Add2(ref int a, int b)
++ {
++ return ref a;
++ }
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-ref-09.cs b/mcs/tests/test-ref-09.cs
+new file mode 100644
+index 00000000000..5d0e89e5c1a
+--- /dev/null
++++ b/mcs/tests/test-ref-09.cs
+@@ -0,0 +1,12 @@
++struct rigidbody { public float x; }
++
++class Program
++{
++ static rigidbody a;
++ static ref rigidbody property_returning_struct_by_ref => ref a;
++
++ static void Main()
++ {
++ System.Console.WriteLine (property_returning_struct_by_ref.x);
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-ref-10.cs b/mcs/tests/test-ref-10.cs
+new file mode 100644
+index 00000000000..88e201d3174
+--- /dev/null
++++ b/mcs/tests/test-ref-10.cs
+@@ -0,0 +1,24 @@
++// Compiler options: -langversion:latest
++
++using System;
++
++ref struct ValueStringBuilder
++{
++ public override string ToString ()
++ {
++ return "aaa";
++ }
++}
++
++
++class X
++{
++ public static int Main ()
++ {
++ var s = new ValueStringBuilder ();
++ if (s.ToString () != "aaa")
++ return 1;
++
++ return 0;
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-tuple-07.cs b/mcs/tests/test-tuple-07.cs
+new file mode 100644
+index 00000000000..cc7ce5837ce
+--- /dev/null
++++ b/mcs/tests/test-tuple-07.cs
+@@ -0,0 +1,16 @@
++using System;
++using System.Collections.Generic;
++
++// Parser tests
++
++class ParserTest
++{
++ IEnumerable<(Object vertex, int distance)> Test ()
++ {
++ return null;
++ }
++
++ public static void Main ()
++ {
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/test-tuple-09.cs b/mcs/tests/test-tuple-09.cs
+new file mode 100644
+index 00000000000..3f15cae6cf1
+--- /dev/null
++++ b/mcs/tests/test-tuple-09.cs
+@@ -0,0 +1,19 @@
++using System;
++
++class TupleDeconstructionDeclaration
++{
++ public static int Main ()
++ {
++ (string s, long l) = GetValues ();
++ (var vs, var vl) = GetValues ();
++ (object o, var vl2) = GetValues ();
++ (string ds, _) = GetValues ();
++
++ return 0;
++ }
++
++ static (string, long) GetValues ()
++ {
++ return ("a", 3);
++ }
++}
+\ No newline at end of file
+diff --git a/mcs/tests/ver-il-net_4_x.xml b/mcs/tests/ver-il-net_4_x.xml
+index c2c98123305..4dbc7042a8a 100644
+--- a/mcs/tests/ver-il-net_4_x.xml
++++ b/mcs/tests/ver-il-net_4_x.xml
+@@ -14659,6 +14659,9 @@
+ <method name="Void Test_22(Boolean)" attrs="129">
+ <size>24</size>
+ </method>
++ <method name="Void Test_23(System.String)" attrs="129">
++ <size>16</size>
++ </method>
+ </type>
+ </test>
+ <test name="gtest-410.cs">
+@@ -52808,6 +52811,19 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-948.cs">
++ <type name="X">
++ <method name="Void Main()" attrs="150">
++ <size>16</size>
++ </method>
++ <method name="Void Foo()" attrs="129">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-95.cs">
+ <type name="X">
+ <method name="Int32 Main()" attrs="150">
+@@ -66893,6 +66909,117 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-async-94.cs">
++ <type name="MyTask`1[T]">
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="MyTask">
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="MyTaskMethodBuilder">
++ <method name="MyTaskMethodBuilder Create()" attrs="150">
++ <size>10</size>
++ </method>
++ <method name="MyTask get_Task()" attrs="2182">
++ <size>10</size>
++ </method>
++ <method name="Void SetException(System.Exception)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void SetResult()" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void AwaitOnCompleted[TAwaiter,TStateMachine](TAwaiter ByRef, TStateMachine ByRef)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void AwaitUnsafeOnCompleted[TAwaiter,TStateMachine](TAwaiter ByRef, TStateMachine ByRef)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void Start[TStateMachine](TStateMachine ByRef)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void SetStateMachine(System.Runtime.CompilerServices.IAsyncStateMachine)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="MyTaskMethodBuilder`1[T]">
++ <method name="MyTaskMethodBuilder`1[T] Create()" attrs="150">
++ <size>10</size>
++ </method>
++ <method name="MyTask`1[T] get_Task()" attrs="2182">
++ <size>10</size>
++ </method>
++ <method name="Void SetException(System.Exception)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void SetResult(T)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void AwaitOnCompleted[TAwaiter,TStateMachine](TAwaiter ByRef, TStateMachine ByRef)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void AwaitUnsafeOnCompleted[TAwaiter,TStateMachine](TAwaiter ByRef, TStateMachine ByRef)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void Start[TStateMachine](TStateMachine ByRef)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void SetStateMachine(System.Runtime.CompilerServices.IAsyncStateMachine)" attrs="134">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="X">
++ <method name="MyTask Test()" attrs="134">
++ <size>33</size>
++ </method>
++ <method name="MyTask`1[System.Int32] Test2()" attrs="134">
++ <size>33</size>
++ </method>
++ <method name="System.Threading.Tasks.ValueTask`1[System.String] Test3()" attrs="134">
++ <size>33</size>
++ </method>
++ <method name="Void Main()" attrs="150">
++ <size>23</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="X+<Test>c__async0">
++ <method name="Void MoveNext()" attrs="486">
++ <size>157</size>
++ </method>
++ <method name="Void SetStateMachine(System.Runtime.CompilerServices.IAsyncStateMachine)" attrs="486">
++ <size>13</size>
++ </method>
++ </type>
++ <type name="X+<Test2>c__async1">
++ <method name="Void MoveNext()" attrs="486">
++ <size>165</size>
++ </method>
++ <method name="Void SetStateMachine(System.Runtime.CompilerServices.IAsyncStateMachine)" attrs="486">
++ <size>13</size>
++ </method>
++ </type>
++ <type name="X+<Test3>c__async2">
++ <method name="Void MoveNext()" attrs="486">
++ <size>169</size>
++ </method>
++ <method name="Void SetStateMachine(System.Runtime.CompilerServices.IAsyncStateMachine)" attrs="486">
++ <size>13</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-cls-00.cs">
+ <type name="CLSCLass_6">
+ <method name="Void add_Disposed(Delegate)" attrs="2182">
+@@ -68527,6 +68654,47 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-default-01.cs">
++ <type name="X">
++ <method name="Void Main()" attrs="150">
++ <size>53</size>
++ </method>
++ <method name="Int32 M1()" attrs="145">
++ <size>10</size>
++ </method>
++ <method name="Void M2()" attrs="145">
++ <size>31</size>
++ </method>
++ <method name="Void M3(Int32)" attrs="145">
++ <size>2</size>
++ </method>
++ <method name="System.Func`1[System.Int32] M4()" attrs="145">
++ <size>38</size>
++ </method>
++ <method name="Int32 <M4>m__0()" attrs="145">
++ <size>9</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-default-02.cs">
++ <type name="C">
++ <method name="Void Main()" attrs="145">
++ <size>36</size>
++ </method>
++ <method name="Void M[T](T, T)" attrs="145">
++ <size>2</size>
++ </method>
++ <method name="Void M2(System.Object[])" attrs="145">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ <method name="Byte[] Test(S`1[System.Byte])" attrs="145">
++ <size>10</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-dictinit-01.cs">
+ <type name="Program">
+ <method name="Int32 Main()" attrs="145">
+@@ -68610,6 +68778,30 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-discards-01.cs">
++ <type name="X">
++ <method name="Void Main()" attrs="150">
++ <size>63</size>
++ </method>
++ <method name="Boolean TryGetValue(Int32 ByRef)" attrs="145">
++ <size>13</size>
++ </method>
++ <method name="Int32 TestValue()" attrs="145">
++ <size>10</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="X+<Main>c__AnonStorey0">
++ <method name="System.Object <>m__0()" attrs="131">
++ <size>25</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-ex-filter-01.cs">
+ <type name="X">
+ <method name="Int32 Main()" attrs="150">
+@@ -70689,6 +70881,19 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-named-11.cs">
++ <type name="X">
++ <method name="Void Main()" attrs="150">
++ <size>13</size>
++ </method>
++ <method name="Void Test(Int32, System.String)" attrs="145">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-nameof-01.cs">
+ <type name="X">
+ <method name="Int32 Main()" attrs="150">
+@@ -72778,6 +72983,49 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-readonly-02.cs">
++ <type name="D">
++ <method name="Int32& Invoke(Int32)" attrs="454">
++ <size>0</size>
++ </method>
++ <method name="System.IAsyncResult BeginInvoke(Int32, System.AsyncCallback, System.Object)" attrs="454">
++ <size>0</size>
++ </method>
++ <method name="Int32& EndInvoke(System.IAsyncResult)" attrs="454">
++ <size>0</size>
++ </method>
++ <method name="Void .ctor(Object, IntPtr)" attrs="6278">
++ <size>0</size>
++ </method>
++ </type>
++ <type name="X">
++ <method name="Void Main()" attrs="150">
++ <size>2</size>
++ </method>
++ <method name="System.Guid& TestMethod()" attrs="129">
++ <size>15</size>
++ </method>
++ <method name="System.Guid& get_TestProp()" attrs="2177">
++ <size>17</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-readonly-03.cs">
++ <type name="S">
++ <method name="Void Main()" attrs="150">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor(Int32)" attrs="6278">
++ <size>13</size>
++ </method>
++ <method name="Void .cctor()" attrs="6289">
++ <size>15</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-ref-01.cs">
+ <type name="X">
+ <method name="Void Main()" attrs="150">
+@@ -72906,6 +73154,95 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-ref-07.cs">
++ <type name="Test">
++ <method name="Void Main()" attrs="150">
++ <size>18</size>
++ </method>
++ <method name="Test Method()" attrs="129">
++ <size>18</size>
++ </method>
++ </type>
++ <type name="P">
++ <method name="Test get_Span()" attrs="3526">
++ <size>0</size>
++ </method>
++ <method name="Void .ctor()" attrs="6276">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-ref-08.cs">
++ <type name="ClassLibrary1.C">
++ <method name="Void MM()" attrs="129">
++ <size>60</size>
++ </method>
++ <method name="Void Main()" attrs="150">
++ <size>245</size>
++ </method>
++ <method name="Int32& Add2(Int32 ByRef, Int32)" attrs="150">
++ <size>10</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ <method name="Void .cctor()" attrs="6289">
++ <size>12</size>
++ </method>
++ </type>
++ <type name="ClassLibrary1.C+B">
++ <method name="Int32& get_Item(Int32)" attrs="2182">
++ <size>15</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="ClassLibrary1.C+Gen`1[T]">
++ <method name="T& get_Item(Int32)" attrs="2182">
++ <size>15</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="ClassLibrary1.C+BB">
++ <method name="Val& get_Item(Int32)" attrs="2182">
++ <size>15</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-ref-09.cs">
++ <type name="Program">
++ <method name="rigidbody& get_property_returning_struct_by_ref()" attrs="2193">
++ <size>13</size>
++ </method>
++ <method name="Void Main()" attrs="145">
++ <size>17</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-ref-10.cs">
++ <type name="ValueStringBuilder">
++ <method name="System.String ToString()" attrs="198">
++ <size>14</size>
++ </method>
++ </type>
++ <type name="X">
++ <method name="Int32 Main()" attrs="150">
++ <size>47</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-static-using-01.cs">
+ <type name="A.B.X">
+ <method name="Int32 Test()" attrs="150">
+@@ -73374,6 +73711,56 @@
+ </method>
+ </type>
+ </test>
++ <test name="test-tuple-07.cs">
++ <type name="ParserTest">
++ <method name="System.Collections.Generic.IEnumerable`1[System.ValueTuple`2[System.Object,System.Int32]] Test()" attrs="129">
++ <size>10</size>
++ </method>
++ <method name="Void Main()" attrs="150">
++ <size>2</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-tuple-08.cs">
++ <type name="X">
++ <method name="Void Main()" attrs="150">
++ <size>19</size>
++ </method>
++ <method name="System.Threading.Tasks.Task Test()" attrs="129">
++ <size>41</size>
++ </method>
++ <method name="System.Threading.Tasks.Task`1[System.ValueTuple`2[System.Int32,System.Int32]] Waiting()" attrs="129">
++ <size>21</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ <type name="X+<Test>c__async0">
++ <method name="Void MoveNext()" attrs="486">
++ <size>212</size>
++ </method>
++ <method name="Void SetStateMachine(System.Runtime.CompilerServices.IAsyncStateMachine)" attrs="486">
++ <size>13</size>
++ </method>
++ </type>
++ </test>
++ <test name="test-tuple-09.cs">
++ <type name="TupleDeconstructionDeclaration">
++ <method name="Int32 Main()" attrs="150">
++ <size>99</size>
++ </method>
++ <method name="System.ValueTuple`2[System.String,System.Int64] GetValues()" attrs="145">
++ <size>21</size>
++ </method>
++ <method name="Void .ctor()" attrs="6278">
++ <size>7</size>
++ </method>
++ </type>
++ </test>
+ <test name="test-var-01.cs">
+ <type name="Test">
+ <method name="Int32 Main()" attrs="150">
--
Efraim Flashner <efraim <at> flashner.co.il> אפרים פלשנר
GPG key = A28B F40C 3E55 1372 662D 14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.