c++: Improve C++'s -Wshadow; fix PRs 16 and 713
Neil Booth
neil@daikokuya.demon.co.uk
Tue Nov 6 21:34:00 GMT 2001
Neil Booth wrote:-
> -Wshadow warns about shadowing class names and global function names,
> (the above two PRs, respectively) contrary to its documentation.
[...]
The patch I posted regressed with g++-mike/for3.C, which I didn't
originally notice. A small tweak fixes this.
OK for the final patch below? (all my recent gcc-testresults posts
include this patch).
Neil.
* cp/decl.c (shadow_warning): New function.
(pushdecl): Improve -Wshadow warnings. Don't give both a warning
and an error when a block scope decl shadows a parameter.
* g++.dg/warn/Wshadow-1.C: New tests.
* g++.old-deja/g++.mike/for3.C: Update.
Index: cp/decl.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/decl.c,v
retrieving revision 1.822
diff -u -p -r1.822 decl.c
--- decl.c 2001/10/23 09:14:11 1.822
+++ decl.c 2001/11/07 05:32:03
@@ -147,6 +147,7 @@ static tree push_cp_library_fn PARAMS ((
static tree build_cp_library_fn PARAMS ((tree, enum tree_code, tree));
static void store_parm_decls PARAMS ((tree));
static int cp_missing_noreturn_ok_p PARAMS ((tree));
+static void shadow_warning PARAMS ((const char *, tree, tree));
#if defined (DEBUG_CP_BINDING_LEVELS)
static void indent PARAMS ((void));
@@ -3788,6 +3789,20 @@ duplicate_decls (newdecl, olddecl)
return 1;
}
+/* Output a -Wshadow warning MSGID, if non-NULL, and give the location
+ of the previous declaration. */
+static void
+shadow_warning (msgid, name, decl)
+ const char *msgid;
+ tree name, decl;
+{
+ warning ("declaration of `%s' shadows %s", IDENTIFIER_POINTER (name), msgid);
+ warning_with_file_and_line (DECL_SOURCE_FILE (decl),
+ DECL_SOURCE_LINE (decl),
+ "shadowed declaration is here");
+}
+
+
/* Record a decl-node X as belonging to the current lexical scope.
Check for errors (such as an incompatible declaration for the same
name already seen in the same scope).
@@ -4173,47 +4188,53 @@ pushdecl (x)
if (oldlocal != NULL_TREE && !DECL_EXTERNAL (x)
/* Inline decls shadow nothing. */
&& !DECL_FROM_INLINE (x)
- && TREE_CODE (oldlocal) == PARM_DECL
- /* Don't complain if it's from an enclosing function. */
- && DECL_CONTEXT (oldlocal) == current_function_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. */
- struct binding_level *b = current_binding_level->level_chain;
-
- if (cleanup_label)
- b = b->level_chain;
-
- /* ARM $8.3 */
- if (b->parm_flag == 1)
- cp_error ("declaration of `%#D' shadows a parameter", name);
+ bool err = false;
+
+ /* Don't complain if it's from an enclosing function. */
+ if (DECL_CONTEXT (oldlocal) == current_function_decl
+ && TREE_CODE (x) != PARM_DECL)
+ {
+ /* Go to where the parms should be and see if we find
+ them there. */
+ struct binding_level *b = current_binding_level->level_chain;
+
+ if (cleanup_label)
+ b = b->level_chain;
+
+ /* ARM $8.3 */
+ if (b->parm_flag == 1)
+ {
+ cp_error ("declaration of `%#D' shadows a parameter",
+ name);
+ err = true;
+ }
+ }
+
+ if (warn_shadow && !err)
+ shadow_warning ("a parameter", name, oldlocal);
}
/* Maybe warn if shadowing something else. */
- if (warn_shadow && !DECL_EXTERNAL (x)
- /* Inline decls shadow nothing. */
- && !DECL_FROM_INLINE (x)
+ else if (warn_shadow && !DECL_EXTERNAL (x)
/* No shadow warnings for internally generated vars. */
&& ! DECL_ARTIFICIAL (x)
/* No shadow warnings for vars made for inlining. */
&& ! DECL_FROM_INLINE (x))
{
- if (oldlocal != NULL_TREE && TREE_CODE (oldlocal) == PARM_DECL)
- warning ("declaration of `%s' shadows a parameter",
- IDENTIFIER_POINTER (name));
- else if (IDENTIFIER_CLASS_VALUE (name) != NULL_TREE
+ if (IDENTIFIER_CLASS_VALUE (name) != NULL_TREE
&& current_class_ptr
&& !TREE_STATIC (name))
- warning ("declaration of `%s' shadows a member of `this'",
- IDENTIFIER_POINTER (name));
- else if (oldlocal != NULL_TREE)
- warning ("declaration of `%s' shadows previous local",
- IDENTIFIER_POINTER (name));
- else if (oldglobal != NULL_TREE)
+ cp_warning ("declaration of `%s' shadows a member of `this'",
+ IDENTIFIER_POINTER (name));
+ else if (oldlocal != NULL_TREE
+ && TREE_CODE (oldlocal) == VAR_DECL)
+ shadow_warning ("a previous local", name, oldlocal);
+ else if (oldglobal != NULL_TREE
+ && TREE_CODE (oldglobal) == VAR_DECL)
/* XXX shadow warnings in outer-more namespaces */
- warning ("declaration of `%s' shadows global declaration",
- IDENTIFIER_POINTER (name));
+ shadow_warning ("a global declaration", name, oldglobal);
}
}
Index: testsuite/g++.dg/warn/Wshadow-1.C
===================================================================
RCS file: Wshadow-1.C
diff -N Wshadow-1.C
--- /dev/null Tue May 5 13:32:27 1998
+++ Wshadow-1.C Tue Nov 6 21:32:03 2001
@@ -0,0 +1,42 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc. */
+
+/* { dg-do compile } */
+/* { dg-options -Wshadow } */
+
+/* Source: Neil Booth, 3 Nov 2001, and PR 16, 713. -Wshadow was
+ giving a bunch of warnings we didn't want, and wasn't giving the
+ location of the shadowed variable. */
+
+struct status // { dg-bogus "shadowed declaration" }
+{
+ int member;
+ void foo2 ();
+
+ inline static int foo3 (int member) // { dg-bogus "shadows" }
+ {
+ return member;
+ }
+};
+
+int decl1; // { dg-warning "shadowed declaration" }
+int decl2; // { dg-warning "shadowed declaration" }
+void foo (struct status &status,// { dg-bogus "shadows a global decl" }
+ double decl1)
+{ // { dg-warning "shadows a global decl" }
+}
+
+void foo1 (int d)
+{
+ double d; // { dg-error "shadows a parameter" }
+}
+
+// { dg-error "In member function" "ignored" { target *-*-* } 0 }
+void status::foo2 ()
+{
+ int member; // { dg-warning "shadows a member" }
+ int decl2; // { dg-warning "shadows a global decl" }
+ int local; // { dg-warning "shadowed declaration" }
+ {
+ int local; // { dg-warning "shadows a previous local" }
+ }
+}
Index: testsuite/g++.old-deja/g++.mike/for3.C
===================================================================
RCS file: /cvs/gcc/gcc/gcc/testsuite/g++.old-deja/g++.mike/for3.C,v
retrieving revision 1.1
diff -u -p -r1.1 for3.C
--- for3.C 2000/01/27 23:19:47 1.1
+++ for3.C 2001/11/07 05:32:03
@@ -1,9 +1,9 @@
// Special g++ Options: -Wshadow
int
-main(int i) {
- for(int i=1; i < 3; i++); // WARNING - shadows parm
- for(int i=1; i < 3; i++); // WARNING - shadows parm
+main(int i) { // WARNING - shadowed decl
+ for(int i=1; i < 3; i++); // WARNING - declaration of
+ for(int i=1; i < 3; i++); // WARNING - declaration of
for(int j=1; j < 3; j++);
for(int j=1; j < 3; j++);
}
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