re PR c++/30566 (-Wshadow warns about clashes between nested function parameters in C++)

gcc/cp/
2010-05-14  Shujing Zhao  <pearly.zhao@oracle.com>

        PR c++/30566
        * name-lookup.c (pushdecl_maybe_friend): Avoid the warnings about
        shadowing the outer parameter or variables by the declaration of
        nested function in nested structure or class. Warn the shadowing by
        the declaration of nested lambda expression.

gcc/testsuite/
2010-05-14  Shujing Zhao  <pearly.zhao@oracle.com>

        PR c++/30566
        * testsuite/g++.dg/warn/Wshadow-4.C: Adjust.
        * testsuite/g++.dg/warn/Wshadow-5.C: New test.
        * testsuite/g++.dg/warn/Wshadow-6.C: New test.

From-SVN: r159383

1 files changed, 38 insertions, 18 deletions

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 88a3e39..405bf16 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -1016,15 +1016,18 @@ pushdecl_maybe_friend (tree x, bool is_friend)
 	  else if (oldlocal != NULL_TREE && !DECL_EXTERNAL (x)
 		   /* Inline decls shadow nothing.  */
 		   && !DECL_FROM_INLINE (x)
-		   && TREE_CODE (oldlocal) == PARM_DECL
+		   && (TREE_CODE (oldlocal) == PARM_DECL
+		       || TREE_CODE (oldlocal) == VAR_DECL)
 		   /* Don't check the `this' parameter.  */
-		   && !DECL_ARTIFICIAL (oldlocal))
+		   && !DECL_ARTIFICIAL (oldlocal)
+		   && !DECL_ARTIFICIAL (x))
 	    {
-	      bool err = false;
+	      bool nowarn = false;
 
 	      /* Don't complain if it's from an enclosing function.  */
 	      if (DECL_CONTEXT (oldlocal) == current_function_decl
-		  && TREE_CODE (x) != PARM_DECL)
+		  && TREE_CODE (x) != PARM_DECL
+		  && TREE_CODE (oldlocal) == PARM_DECL)
 		{
 		  /* Go to where the parms should be and see if we find
 		     them there.  */
@@ -1038,16 +1041,41 @@ pushdecl_maybe_friend (tree x, bool is_friend)
 		  if (b->kind == sk_function_parms)
 		    {
 		      error ("declaration of %q#D shadows a parameter", x);
-		      err = true;
+		      nowarn = true;
 		    }
 		}
 
-	      if (warn_shadow && !err)
+	      /* The local structure or class can't use parameters of
+		 the containing function anyway.  */
+	      if (DECL_CONTEXT (oldlocal) != current_function_decl)
 		{
-		  warning_at (input_location, OPT_Wshadow,
-			      "declaration of %q#D shadows a parameter", x);
-		  warning_at (DECL_SOURCE_LOCATION (oldlocal), OPT_Wshadow,
-			      "shadowed declaration is here");
+		  cxx_scope *scope = current_binding_level;
+		  tree context = DECL_CONTEXT (oldlocal);
+		  for (; scope; scope = scope->level_chain)
+		   {
+		     if (scope->kind == sk_function_parms
+			 && scope->this_entity == context)
+		      break;
+		     if (scope->kind == sk_class
+			 && !LAMBDA_TYPE_P (scope->this_entity))
+		       {
+			 nowarn = true;
+			 break;
+		       }
+		   }
+		}
+
+	      if (warn_shadow && !nowarn)
+		{
+		  if (TREE_CODE (oldlocal) == PARM_DECL)
+		    warning_at (input_location, OPT_Wshadow,
+				"declaration of %q#D shadows a parameter", x);
+		  else
+		    warning_at (input_location, OPT_Wshadow,
+				"declaration of %qD shadows a previous local",
+				x);
+		   warning_at (DECL_SOURCE_LOCATION (oldlocal), OPT_Wshadow,
+			       "shadowed declaration is here");
 		}
 	    }
 
@@ -1074,14 +1102,6 @@ pushdecl_maybe_friend (tree x, bool is_friend)
 		  warning (OPT_Wshadow, "declaration of %qD shadows a member of 'this'",
 			   x);
 		}
-	      else if (oldlocal != NULL_TREE
-		       && TREE_CODE (oldlocal) == VAR_DECL)
-		{
-		  warning_at (input_location, OPT_Wshadow,
-			      "declaration of %qD shadows a previous local", x);
-		  warning_at (DECL_SOURCE_LOCATION (oldlocal), OPT_Wshadow,
-			      "shadowed declaration is here");
-		}
 	      else if (oldglobal != NULL_TREE
 		       && TREE_CODE (oldglobal) == VAR_DECL)
 		/* XXX shadow warnings in outer-more namespaces */