re PR c/17188 (struct Foo { } redefinition)

	PR c/17188
	* c-decl.c (diagnose_mismatched_decls): Check for duplicate
	declarations of enumerators.
	(start_struct): Check TYPE_SIZE rather than TYPE_FIELDS to check
	for redefinition.  Check for nested redefinition.
	(finish_struct): Don't check for nested redefinition.
	(start_enum): Check for nested redefinition.

testsuite:
	* gcc.dg/nested-redef-1.c, gcc.dg/pr17188-1.c: New tests.
	* gcc.dg/decl-3.c: Adjust expected message.

From-SVN: r88063

gcc/ChangeLog

+2004-09-24  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	PR c/17188
+	* c-decl.c (diagnose_mismatched_decls): Check for duplicate
+	declarations of enumerators.
+	(start_struct): Check TYPE_SIZE rather than TYPE_FIELDS to check
+	for redefinition.  Check for nested redefinition.
+	(finish_struct): Don't check for nested redefinition.
+	(start_enum): Check for nested redefinition.
+
 2004-09-24  Devang Patel  <dpatel@apple.com>
 
 	* tree-if-conv.c (tree_if_convert_cond_expr0: Create temp. variable

gcc/c-decl.c

@@ -1145,6 +1145,15 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl,
       return false;
     }
 
+  /* Enumerators have no linkage, so may only be declared once in a
+     given scope.  */
+  if (TREE_CODE (olddecl) == CONST_DECL)
+    {
+      error ("%Jredeclaration of enumerator %qD", newdecl, newdecl);
+      locate_old_decl (olddecl, error);
+      return false;
+    }
+
   if (!comptypes (oldtype, newtype))
     {
       if (TREE_CODE (olddecl) == FUNCTION_DECL
@@ -4910,13 +4919,22 @@ start_struct (enum tree_code code, tree name)
     ref = lookup_tag (code, name, 1);
   if (ref && TREE_CODE (ref) == code)
     {
-      if (TYPE_FIELDS (ref))
+      if (TYPE_SIZE (ref))
         {
 	  if (code == UNION_TYPE)
 	    error ("redefinition of %<union %s%>", IDENTIFIER_POINTER (name));
           else
 	    error ("redefinition of %<struct %s%>", IDENTIFIER_POINTER (name));
 	}
+      else if (C_TYPE_BEING_DEFINED (ref))
+	{
+	  if (code == UNION_TYPE)
+	    error ("nested redefinition of %<union %s%>",
+		   IDENTIFIER_POINTER (name));
+          else
+	    error ("nested redefinition of %<struct %s%>",
+		   IDENTIFIER_POINTER (name));
+	}
     }
   else
     {
@@ -5123,11 +5141,6 @@ finish_struct (tree t, tree fieldlist, tree attributes)
       if (C_DECL_VARIABLE_SIZE (x))
 	C_TYPE_VARIABLE_SIZE (t) = 1;
 
-      /* Detect invalid nested redefinition.  */
-      if (TREE_TYPE (x) == t)
-	error ("nested redefinition of %qs",
-	       IDENTIFIER_POINTER (TYPE_NAME (t)));
-
       if (DECL_INITIAL (x))
 	{
 	  unsigned HOST_WIDE_INT width = tree_low_cst (DECL_INITIAL (x), 1);
@@ -5330,6 +5343,9 @@ start_enum (tree name)
       pushtag (name, enumtype);
     }
 
+  if (C_TYPE_BEING_DEFINED (enumtype))
+    error ("nested redefinition of %<enum %s%>", IDENTIFIER_POINTER (name));
+
   C_TYPE_BEING_DEFINED (enumtype) = 1;
 
   if (TYPE_VALUES (enumtype) != 0)

gcc/testsuite/ChangeLog

+2004-09-24  Joseph S. Myers  <jsm@polyomino.org.uk>
+
+	PR c/17188
+	* gcc.dg/nested-redef-1.c, gcc.dg/pr17188-1.c: New tests.
+	* gcc.dg/decl-3.c: Adjust expected message.
+
 2004-09-24  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
 
 	PR fortran/17615

gcc/testsuite/gcc.dg/decl-3.c

@@ -2,4 +2,4 @@
 /* { dg-do compile } */
 
 enum { CODES }; /* { dg-error "previous definition" } */
-enum { CODES }; /* { dg-error "conflicting types" } */
+enum { CODES }; /* { dg-error "conflicting types|redeclaration of enumerator" } */

gcc/testsuite/gcc.dg/nested-redef-1.c

+/* Test diagnosis of nested tag redefinitions.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+struct s0 {
+  struct s0 { int a; } x; /* { dg-error "error: nested redefinition of 'struct s0'" } */
+};
+
+struct s1 {
+  const struct s1 { int b; } x; /* { dg-error "error: nested redefinition of 'struct s1'" } */
+};
+
+struct s2 {
+  struct s2 { int c; } *x; /* { dg-error "error: nested redefinition of 'struct s2'" } */
+};
+
+struct s3 {
+  struct s4 {
+    struct s5 {
+      struct s3 { int a; } **x; /* { dg-error "error: nested redefinition of 'struct s3'" } */
+    } y;
+  } z;
+};
+
+struct s6;
+struct s6 { struct s6 *p; };
+
+union u0 {
+  union u0 { int c; } *x; /* { dg-error "error: nested redefinition of 'union u0'" } */
+};
+
+enum e0 {
+  E0 = sizeof(enum e0 { E1 }) /* { dg-error "error: nested redefinition of 'enum e0'" } */
+};
+
+enum e1 {
+  E2 = sizeof(enum e2 { E2 }), /* { dg-error "error: redeclaration of enumerator 'E2'" } */
+  /* { dg-error "previous definition" "previous E2" { target *-*-* } 38 } */
+  E3
+};
+
+enum e3;
+enum e3 { E4 = 0 };

gcc/testsuite/gcc.dg/pr17188-1.c

+/* A redefinition of an empty struct should be diagnosed the same as a
+   redefinition of any other tag, but formerly only s2 and s4 were
+   diagnosed.  Bug 17188.  */
+/* Origin: Joseph Myers <jsm@polyomino.org.uk> */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+struct s0 { };
+struct s0;
+struct s0 { }; /* { dg-error "error: redefinition of 'struct s0'" } */
+
+struct s1 { };
+struct s1 { }; /* { dg-error "error: redefinition of 'struct s1'" } */
+
+struct s2 { int a : 1; };
+struct s2 { int a : 1; }; /* { dg-error "error: redefinition of 'struct s2'" } */
+
+struct s3 { };
+struct s3 { int a : 1; }; /* { dg-error "error: redefinition of 'struct s3'" } */
+
+struct s4 { int a : 1; };
+struct s4 { }; /* { dg-error "error: redefinition of 'struct s4'" } */
+
+struct s5 { int a : 1; };
+struct s5;
+
+struct s6;
+struct s6 { int a : 1; };
+
+struct s7;
+struct s7 { };