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.

From-SVN: r254093

1 files changed, 31 insertions, 5 deletions

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 6b84324..68c45fd 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -2241,11 +2241,37 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
 	}
       if (!start_function (specs, declarator, all_prefix_attrs))
 	{
-	  /* This can appear in many cases looking nothing like a
-	     function definition, so we don't give a more specific
-	     error suggesting there was one.  */
-	  c_parser_error (parser, "expected %<=%>, %<,%>, %<;%>, %<asm%> "
-			  "or %<__attribute__%>");
+	  /* At this point we've consumed:
+	       declaration-specifiers declarator
+	     and the next token isn't CPP_EQ, CPP_COMMA, CPP_SEMICOLON,
+	     RID_ASM, RID_ATTRIBUTE, or RID_IN,
+	     but the
+	       declaration-specifiers declarator
+	     aren't grokkable as a function definition, so we have
+	     an error.  */
+	  gcc_assert (!c_parser_next_token_is (parser, CPP_SEMICOLON));
+	  if (c_parser_next_token_starts_declspecs (parser))
+	    {
+	      /* If we have
+		   declaration-specifiers declarator decl-specs
+		 then assume we have a missing semicolon, which would
+		 give us:
+		   declaration-specifiers declarator  decl-specs
+						    ^
+						    ;
+		   <~~~~~~~~~ declaration ~~~~~~~~~~>
+		 Use c_parser_require to get an error with a fix-it hint.  */
+	      c_parser_require (parser, CPP_SEMICOLON, "expected %<;%>");
+	      parser->error = false;
+	    }
+	  else
+	    {
+	      /* This can appear in many cases looking nothing like a
+		 function definition, so we don't give a more specific
+		 error suggesting there was one.  */
+	      c_parser_error (parser, "expected %<=%>, %<,%>, %<;%>, %<asm%> "
+			      "or %<__attribute__%>");
+	    }
 	  if (nested)
 	    c_pop_function_context ();
 	  break;