re PR c++/57709 (-Wshadow is too strict / has false positives)

gcc/cp/ChangeLog:

2014-08-22  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR c++/57709
	* name-lookup.c (pushdecl_maybe_friend_1): Do not warn if a
	declaration shadows a function declaration, unless the former
	declares a function, pointer to function or pointer to member
	function, because this is a common and valid case in real-world
	code.
	* cp-tree.h (TYPE_PTRFN_P,TYPE_REFFN_P,TYPE_PTRMEMFUNC_P):
	Improve description.

gcc/testsuite/ChangeLog:

2014-08-22  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR c++/57709
	* g++.dg/Wshadow.C: New test.

From-SVN: r214357

5 files changed, 52 insertions, 7 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 649941c..2ea2665 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,14 @@
+2014-08-22  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+	PR c++/57709
+	* name-lookup.c (pushdecl_maybe_friend_1): Do not warn if a
+	declaration shadows a function declaration, unless the former
+	declares a function, pointer to function or pointer to member
+	function, because this is a common and valid case in real-world
+	code.
+	* cp-tree.h (TYPE_PTRFN_P,TYPE_REFFN_P,TYPE_PTRMEMFUNC_P):
+	Improve description.
+
 2014-08-22  Jason Merrill  <jason@redhat.com>
 
 	PR c++/62129
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 34373b7..81c7fd6 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -3558,18 +3558,17 @@ more_aggr_init_expr_args_p (const aggr_init_expr_arg_iterator *iter)
    && !(TREE_CODE (TREE_TYPE (NODE)) == FUNCTION_TYPE		\
 	|| TREE_CODE (TREE_TYPE (NODE)) == METHOD_TYPE))
 
-/* Returns true if NODE is a pointer to function.  */
+/* Returns true if NODE is a pointer to function type.  */
 #define TYPE_PTRFN_P(NODE)				\
   (TYPE_PTR_P (NODE)			                \
    && TREE_CODE (TREE_TYPE (NODE)) == FUNCTION_TYPE)
 
-/* Returns true if NODE is a reference to function.  */
+/* Returns true if NODE is a reference to function type.  */
 #define TYPE_REFFN_P(NODE)				\
   (TREE_CODE (NODE) == REFERENCE_TYPE			\
    && TREE_CODE (TREE_TYPE (NODE)) == FUNCTION_TYPE)
 
-/* Nonzero for _TYPE node means that this type is a pointer to member
-   function type.  */
+/* Returns true if NODE is a pointer to member function type.  */
 #define TYPE_PTRMEMFUNC_P(NODE)		\
   (TREE_CODE (NODE) == RECORD_TYPE	\
    && TYPE_PTRMEMFUNC_FLAG (NODE))
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 6e779a6..ebcbb5c 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -1239,9 +1239,24 @@ pushdecl_maybe_friend_1 (tree x, bool is_friend)
 
 	      if (member && !TREE_STATIC (member))
 		{
-		  /* Location of previous decl is not useful in this case.  */
-		  warning (OPT_Wshadow, "declaration of %qD shadows a member of 'this'",
-			   x);
+		  if (BASELINK_P (member))
+		    member = BASELINK_FUNCTIONS (member);
+		  member = OVL_CURRENT (member);
+	
+		  /* Do not warn if a variable shadows a function, unless
+		     the variable is a function or a pointer-to-function.  */
+		  if (TREE_CODE (member) != FUNCTION_DECL
+		      || TREE_CODE (x) == FUNCTION_DECL
+		      || TYPE_PTRFN_P (TREE_TYPE (x))
+		      || TYPE_PTRMEMFUNC_P (TREE_TYPE (x)))
+		    {
+		      if (warning_at (input_location, OPT_Wshadow,
+				      "declaration of %qD shadows a member of %qT",
+				      x, current_nonlambda_class_type ())
+			  && DECL_P (member))
+			inform (DECL_SOURCE_LOCATION (member),
+				"shadowed declaration is here");
+		    }
 		}
 	      else if (oldglobal != NULL_TREE
 		       && (VAR_P (oldglobal)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a6415d6..ce3e30e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-08-22  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+	PR c++/57709
+	* g++.dg/Wshadow.C: New test.
+
 2014-08-22  Steven Bosscher  <steven@gcc.gnu.org>
 
 	PR fortran/62135
diff --git a/gcc/testsuite/g++.dg/Wshadow.C b/gcc/testsuite/g++.dg/Wshadow.C
new file mode 100644
index 0000000..482d2f0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/Wshadow.C
@@ -0,0 +1,15 @@
+// { dg-do compile }
+// { dg-options "-Wshadow" }
+// PR c++/57709 
+class C {
+  int both_var; // { dg-message "declaration" }
+  void var_and_method(void) {} // { dg-message "declaration" }
+  void m() { 
+    int 
+      both_var,  // { dg-warning "shadows" }
+      var_and_method; 
+  }
+  void m2() { 
+    void (C::*var_and_method)(void); // { dg-warning "shadows" }
+  }
+};