Subject: bug#35194: CC Mode 5.33.1 (C++//l); Indentation of C++ methods with ref-qualifiers is broken.

From: Glenn Morris <[email-masked]>
Date: Mon, 08 Apr 2019 12:18:11 -0400

Report reassigned to cc-mode.

(It seems that cc-mode users not infrequently report bugs from mail
clients that don't support X- headers. So I suggest also putting "Package:
cc-mode" at the start of the message body in c-submit-bug-report.)

Tau wrote:

> Methods with ref-qualifiers (& and &&) seem to get indented with
> "brace-list-intro" which, as I understand it, is used for
> initializer lists and not code blocks. It is set to
> "c-lineup-arglist-intro-after-paren" in GNU style which is the
> default.
>
> Functions that use the auto syntax for return types and return
> a reference are affected as well.
>
> // Example of incorrect indentation in a program:
>
> #include <iostream>
>
> struct T {
>   void a_method() && {
> 		      std::cout << "rvalue ref\n";
>   }
>
>   void a_method() const& {
> 			  std::cout << "lvalue const ref\n";
>   }
>
>   void this_gets_properly_indented() const {
>     std::cout << "without a ref-qualifier\n";
>   }
>
>   auto this_too() && -> void {
>     std::cout << "rvalue ref; '->' notation\n";
>   }
>
>   auto this_breaks_again() -> T& {
> 				  return *this;
>   }
> };
>
> int main() {
>   T x;
>
>   T().a_method();
>   x.a_method();
> }
>
> Emacs  : GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version
> 3.22.30) of 2018-07-05
> Package: CC Mode 5.33.1 (C++//l)
> Buffer Style: gnu
> c-emacs-features: (pps-extended-state col-0-paren posix-char-classes
> gen-string-delim gen-comment-delim syntax-properties 1-bit)
>
> current state:
> ==============
> (setq
>  c-basic-offset 2
>  c-comment-only-line-offset '(0 . 0)
>  c-indent-comment-alist '((anchored-comment column . 0) (end-block
> space . 1) (cpp-end-block space . 2))
>  c-indent-comments-syntactically-p nil
>  c-block-comment-prefix ""
>  c-comment-prefix-regexp '((pike-mode . "//+!?\\|\\**") (awk-mode .
> "#+") (other . "//+\\|\\**"))
>  c-doc-comment-style '((java-mode . javadoc) (pike-mode . autodoc)
> (c-mode . gtkdoc)) c-cleanup-list '(scope-operator)
>  c-hanging-braces-alist '((substatement-open before after)
> (arglist-cont-nonempty)) c-hanging-colons-alist nil
>  c-hanging-semi&comma-criteria '(c-semi&comma-inside-parenlist)
>  c-backslash-column 48
>  c-backslash-max-column 72
>  c-special-indent-hook '(c-gnu-impose-minimum)
>  c-label-minimum-indentation 1
>  c-offsets-alist '((inexpr-class . +)
> 		   (inexpr-statement . +)
> 		   (lambda-intro-cont . +)
> 		   (inlambda . c-lineup-inexpr-block)
> 		   (template-args-cont c-lineup-template-args +)
> 		   (incomposition . +)
> 		   (inmodule . +)
> 		   (innamespace . +)
> 		   (inextern-lang . +)
> 		   (composition-close . 0)
> 		   (module-close . 0)
> 		   (namespace-close . 0)
> 		   (extern-lang-close . 0)
> 		   (composition-open . 0)
> 		   (module-open . 0)
> 		   (namespace-open . 0)
> 		   (extern-lang-open . 0)
> 		   (objc-method-call-cont
> 		    c-lineup-ObjC-method-call-colons
> 		    c-lineup-ObjC-method-call
> 		    +
> 		    )
> 		   (objc-method-args-cont . c-lineup-ObjC-method-args)
> 		   (objc-method-intro . [0])
> 		   (friend . 0)
> 		   (cpp-define-intro c-lineup-cpp-define +)
> 		   (cpp-macro-cont . +)
> 		   (cpp-macro . [0])
> 		   (inclass . +)
> 		   (stream-op . c-lineup-streamop)
> 		   (arglist-cont-nonempty c-lineup-gcc-asm-reg
> c-lineup-arglist) (arglist-cont c-lineup-gcc-asm-reg 0)
> 		   (comment-intro c-lineup-knr-region-comment
> c-lineup-comment) (catch-clause . 0)
> 		   (else-clause . 0)
> 		   (do-while-closure . 0)
> 		   (access-label . -)
> 		   (case-label . 0)
> 		   (substatement . +)
> 		   (statement-case-intro . +)
> 		   (statement . 0)
> 		   (brace-entry-open . 0)
> 		   (brace-list-entry . c-lineup-under-anchor)
> 		   (brace-list-close . 0)
> 		   (block-close . 0)
> 		   (block-open . 0)
> 		   (inher-cont . c-lineup-multi-inher)
> 		   (inher-intro . +)
> 		   (member-init-cont . c-lineup-multi-inher)
> 		   (member-init-intro . +)
> 		   (annotation-var-cont . +)
> 		   (annotation-top-cont . 0)
> 		   (topmost-intro . 0)
> 		   (knr-argdecl . 0)
> 		   (func-decl-cont . +)
> 		   (inline-close . 0)
> 		   (class-close . 0)
> 		   (class-open . 0)
> 		   (defun-block-intro . +)
> 		   (defun-close . 0)
> 		   (defun-open . 0)
> 		   (c . c-lineup-C-comments)
> 		   (string . c-lineup-dont-change)
> 		   (topmost-intro-cont
> 		    first
> 		    c-lineup-topmost-intro-cont
> 		    c-lineup-gnu-DEFUN-intro-cont
> 		    )
> 		   (brace-list-intro .
> c-lineup-arglist-intro-after-paren) (brace-list-open . +)
> 		   (inline-open . 0)
> 		   (arglist-close . c-lineup-arglist)
> 		   (arglist-intro . c-lineup-arglist-intro-after-paren)
> 		   (statement-cont . +)
> 		   (statement-case-open . +)
> 		   (label . 0)
> 		   (substatement-label . 0)
> 		   (substatement-open . +)
> 		   (knr-argdecl-intro . 5)
> 		   (statement-block-intro . +)
> 		   )
>  c-buffer-is-cc-mode 'c++-mode
>  c-tab-always-indent t
>  c-syntactic-indentation t
>  c-syntactic-indentation-in-macros t
>  c-ignore-auto-fill '(string cpp code)
>  c-auto-align-backslashes t
>  c-backspace-function 'backward-delete-char-untabify
>  c-delete-function 'delete-char
>  c-electric-pound-behavior nil
>  c-default-style '((java-mode . "java") (awk-mode . "awk") (other .
> "gnu")) c-enable-xemacs-performance-kludge-p nil
>  c-old-style-variable-behavior nil
>  defun-prompt-regexp nil
>  tab-width 8
>  comment-column 32
>  parse-sexp-ignore-comments t
>  parse-sexp-lookup-properties t
>  auto-fill-function nil
>  comment-multi-line t
>  comment-start-skip "\\(//+\\|/\\*+\\)\\s *"
>  fill-prefix nil
>  fill-column 70
>  paragraph-start "[ 	]*\\(//+\\|\\**\\)[ 	]*$\\|^\f"
>  adaptive-fill-mode t
>  adaptive-fill-regexp
> "[ 	]*\\(//+\\|\\**\\)[ 	]*\\([ 	]*\\([-–!|#%;>*·•‣⁃◦]+[ 	]*\\)*\\)" )