Re: [PATCH] c++: fix wrong fixit hints for misspelled typedef [PR77565]

[David Malcolm <dmalcolm@redhat.com>]

On Tue, 2021-09-14 at 03:35 +0900, Michel Morin via Gcc-patches wrote:
> Hi,
> 
> PR77565 reports that, with the code `typdef int Int;`, GCC emits
> "did you mean 'typeof'?" instead of "did you mean 'typedef'?".
> 
> This happens because the typo corrector determines that `typeof` is a
> candidate for suggestion (through
> `cp_keyword_starts_decl_specifier_p`),
> but `typedef` is not.
> 
> This patch fixes the issue by adding `typedef` as a candidate. The
> patch
> additionally adds the `inline` specifier and cv-specifiers as a
> candidate.
> Here is a patch (tests `make check-gcc` pass on darwin):

Thanks for this patch (and for reporting the bug in the first place).

I notice that, as well as being used for fix-it hints by
lookup_name_fuzzy (indirectly via suggest_rid_p),
cp_keyword_starts_decl_specifier_p is also used by
cp_lexer_next_token_is_decl_specifier_keyword, which is used by
cp_parser_lambda_declarator_opt and cp_parser_constructor_declarator_p.

So I'm not sure if this fix is exactly correct - hopefully one of the
C++ frontend maintainers can chime in.  If
cp_keyword_starts_decl_specifier_p isn't quite the right place for
this, the fix could probably go in suggest_rid_p instead, which *is*
specific to spelling corrections.

Hope this is constructive; thanks again for the patch
Dave



> 
> ============================================
> c++: add typo corrections for typedef/inline/cv-qual [PR77565]
> 
> PR c++/77565
> 
> gcc/cp/ChangeLog:
> 
> * parser.c (cp_keyword_starts_decl_specifier_p): Handle
> typedef/inline specifiers and cv-qualifiers.
> 
> gcc/testsuite/ChangeLog:
> 
> * g++.dg/spellcheck-typenames.C: Add tests for decl-specs.
> 
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -1051,6 +1051,12 @@ cp_keyword_starts_decl_specifier_p (enum rid
> keyword)
>      case RID_FLOAT:
>      case RID_DOUBLE:
>      case RID_VOID:
> +      /* CV qualifiers.  */
> +    case RID_CONST:
> +    case RID_VOLATILE:
> +      /* typedef/inline specifiers.  */
> +    case RID_TYPEDEF:
> +    case RID_INLINE:
>        /* GNU extensions.  */
>      case RID_ATTRIBUTE:
>      case RID_TYPEOF:
> --- a/gcc/testsuite/g++.dg/spellcheck-typenames.C
> +++ b/gcc/testsuite/g++.dg/spellcheck-typenames.C
> @@ -76,3 +76,38 @@ singed char ch; // { dg-error "1: 'singed' does
> not
> name a type; did you mean 's
>   ^~~~~~
>   signed
>     { dg-end-multiline-output "" } */
> +
> +typdef int my_int; // { dg-error "1: 'typdef' does not name a type;
> did you mean 'typedef'?" }
> +/* { dg-begin-multiline-output "" }
> + typdef int my_int;
> + ^~~~~~
> + typedef
> +   { dg-end-multiline-output "" } */
> +
> +inlien int inline_func(); // { dg-error "1: 'inlien' does not name a
> type; did you mean 'inline'?" }
> +/* { dg-begin-multiline-output "" }
> + inlien int inline_func();
> + ^~~~~~
> + inline
> +   { dg-end-multiline-output "" } */
> +
> +coonst int ci = 0; // { dg-error "1: 'coonst' does not name a type;
> did you mean 'const'?" }
> +/* { dg-begin-multiline-output "" }
> + coonst int ci = 0;
> + ^~~~~~
> + const
> +   { dg-end-multiline-output "" } */
> +
> +voltil int vi; // { dg-error "1: 'voltil' does not name a type; did
> you mean 'volatile'?" }
> +/* { dg-begin-multiline-output "" }
> + voltil int vi;
> + ^~~~~~
> + volatile
> +   { dg-end-multiline-output "" } */
> +
> +statik int si; // { dg-error "1: 'statik' does not name a type; did
> you mean 'static'?" }
> +/* { dg-begin-multiline-output "" }
> + statik int si;
> + ^~~~~~
> + static
> +   { dg-end-multiline-output "" } */
> ============================================
> 
> --
> Regards,
> Michel