[Bug c/7356] syntax errors immediately before an #include are reported for within the included file

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=7356

--- Comment #8 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Author: dmalcolm
Date: Wed Oct 25 23:53:41 2017
New Revision: 254093

URL: https://gcc.gnu.org/viewcvs?rev=254093&root=gcc&view=rev
Log:
C: detect more missing semicolons (PR c/7356)

c_parser_declaration_or_fndef has logic for parsing what might be
either a declaration or a function definition.

This patch adds a test to detect cases where a semicolon would have
terminated the decls as a declaration, where the token that follows
would start a new declaration specifier, and updates the error message
accordingly, with a fix-it hint.

This addresses PR c/7356, fixing the case of a stray token before a
#include that previously gave inscrutable output, and improving e.g.:

  int i
  int j;

from:

  t.c:2:1: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'int'
   int j;
   ^~~

to:

  t.c:1:6: error: expected ';' before 'int'
   int i
        ^
        ;
   int j;
   ~~~

gcc.dg/noncompile/920923-1.c needs a slight update, as the output for
the first line changes from:

  920923-1.c:2:14: error: expected '=', ',', ';', 'asm' or
  '__attribute__' before 'unsigned'
   typedef BYTE unsigned char; /* { dg-error "expected" } */
                ^~~~~~~~

to:
  920923-1.c:2:13: error: expected ';' before 'unsigned'
   typedef BYTE unsigned char; /* { dg-error "expected" } */
               ^~~~~~~~~
               ;
  920923-1.c:2:1: warning: useless type name in empty declaration
   typedef BYTE unsigned char; /* { dg-error "expected" } */
   ^~~~~~~

The patch also adds a test for PR c/44515 as a baseline.

gcc/c/ChangeLog:
        PR c/7356
        * c-parser.c (c_parser_declaration_or_fndef): Detect missing
        semicolons.

gcc/testsuite/ChangeLog:
        PR c/7356
        PR c/44515
        * c-c++-common/pr44515.c: New test case.
        * gcc.dg/pr7356-2.c: New test case.
        * gcc.dg/pr7356.c: New test case.
        * gcc.dg/spellcheck-typenames.c: Update the "singed" char "TODO"
        case to reflect changes to output.
        * gcc.dg/noncompile/920923-1.c: Add dg-warning to reflect changes
        to output.


Added:
    trunk/gcc/testsuite/c-c++-common/pr44515.c
    trunk/gcc/testsuite/gcc.dg/pr7356-2.c
    trunk/gcc/testsuite/gcc.dg/pr7356.c
Modified:
    trunk/gcc/c/ChangeLog
    trunk/gcc/c/c-parser.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/noncompile/920923-1.c
    trunk/gcc/testsuite/gcc.dg/spellcheck-typenames.c