Warn about the deprecated string literal -> char* conversion. Fixes PR6428.

llvm-svn: 97404

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1779,7 +1779,8 @@ def err_typecheck_incomplete_array_needs_initializer : Error<
 def err_array_init_not_init_list : Error<
   "array initializer must be an initializer "
   "list%select{| or string literal}0">;
-
+def warn_deprecated_string_literal_conversion : Warning<
+  "conversion from string literal to %0 is deprecated">;
 def err_realimag_invalid_type : Error<"invalid type %0 to %1 operator">;
 def err_typecheck_sclass_fscope : Error<
   "illegal storage class on file-scoped variable">;

clang/lib/Sema/SemaExprCXX.cpp

@@ -1774,6 +1774,11 @@ Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
     ImpCastExprToType(From, ToType.getNonReferenceType(),
                       CastExpr::CK_NoOp,
                       ToType->isLValueReferenceType());
+
+    if (SCS.DeprecatedStringLiteralToCharPtr)
+      Diag(From->getLocStart(), diag::warn_deprecated_string_literal_conversion)
+        << ToType.getNonReferenceType();
+
     break;
       
   default:

clang/lib/Sema/SemaOverload.cpp

@@ -118,7 +118,7 @@ void StandardConversionSequence::setAsIdentityConversion() {
   First = ICK_Identity;
   Second = ICK_Identity;
   Third = ICK_Identity;
-  Deprecated = false;
+  DeprecatedStringLiteralToCharPtr = false;
   ReferenceBinding = false;
   DirectBinding = false;
   RRefBinding = false;
@@ -549,7 +549,7 @@ Sema::IsStandardConversion(Expr* From, QualType ToType,
 
   // Standard conversions (C++ [conv])
   SCS.setAsIdentityConversion();
-  SCS.Deprecated = false;
+  SCS.DeprecatedStringLiteralToCharPtr = false;
   SCS.IncompatibleObjC = false;
   SCS.setFromType(FromType);
   SCS.CopyConstructor = 0;
@@ -592,7 +592,7 @@ Sema::IsStandardConversion(Expr* From, QualType ToType,
 
     if (IsStringLiteralToNonConstPointerConversion(From, ToType)) {
       // This conversion is deprecated. (C++ D.4).
-      SCS.Deprecated = true;
+      SCS.DeprecatedStringLiteralToCharPtr = true;
 
       // For the purpose of ranking in overload resolution
       // (13.3.3.1.1), this conversion is considered an
@@ -1993,7 +1993,7 @@ Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1,
   // the deprecated string literal array to pointer conversion.
   switch (Result) {
   case ImplicitConversionSequence::Better:
-    if (SCS1.Deprecated)
+    if (SCS1.DeprecatedStringLiteralToCharPtr)
       Result = ImplicitConversionSequence::Indistinguishable;
     break;
 
@@ -2001,7 +2001,7 @@ Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1,
     break;
 
   case ImplicitConversionSequence::Worse:
-    if (SCS2.Deprecated)
+    if (SCS2.DeprecatedStringLiteralToCharPtr)
       Result = ImplicitConversionSequence::Indistinguishable;
     break;
   }

clang/lib/Sema/SemaOverload.h

@@ -117,7 +117,7 @@ namespace clang {
     /// Deprecated - Whether this the deprecated conversion of a
     /// string literal to a pointer to non-const character data
     /// (C++ 4.2p2).
-    bool Deprecated : 1;
+    bool DeprecatedStringLiteralToCharPtr : 1;
 
     /// IncompatibleObjC - Whether this is an Objective-C conversion
     /// that we should warn about (if we actually use it).

clang/test/CXX/temp/temp.fct.spec/temp.arg.explicit/p3.cpp

@@ -3,8 +3,9 @@
 template<class X, class Y, class Z> X f(Y,Z); // expected-note {{candidate template ignored: couldn't infer template argument 'X'}}
 
 void g() {
-  f<int,char*,double>("aa",3.0); 
-  f<int,char*>("aa",3.0); // Z is deduced to be double 
+  f<int,char*,double>("aa",3.0); // expected-warning{{conversion from string literal to 'char *' is deprecated}}
+  f<int,char*>("aa",3.0); // Z is deduced to be double  \
+                          // expected-warning{{conversion from string literal to 'char *' is deprecated}}
   f<int>("aa",3.0);       // Y is deduced to be char*, and
                           // Z is deduced to be double 
   f("aa",3.0); // expected-error{{no matching}}

clang/test/SemaCXX/dcl_init_aggr.cpp

@@ -38,7 +38,7 @@ char cv[4] = { 'a', 's', 'd', 'f', 0 }; // expected-error{{excess elements in ar
 
 // C++ [dcl.init.aggr]p7
 struct TooFew { int a; char* b; int c; }; 
-TooFew too_few = { 1, "asdf" }; // okay
+TooFew too_few = { 1, "asdf" }; // expected-warning{{conversion from string literal to 'char *' is deprecated}}
 
 struct NoDefaultConstructor { // expected-note 3 {{candidate constructor (the implicit copy constructor)}} \
                               // expected-note{{declared here}}

clang/test/SemaCXX/overload-call.cpp

@@ -53,7 +53,7 @@ int* k(char*);
 double* k(bool);
 
 void test_k() {
-  int* ip1 = k("foo");
+  int* ip1 = k("foo"); // expected-warning{{conversion from string literal to 'char *' is deprecated}}
   double* dp1 = k(L"foo");
 }
 
@@ -61,7 +61,7 @@ int* l(wchar_t*);
 double* l(bool);
 
 void test_l() {
-  int* ip1 = l(L"foo");
+  int* ip1 = l(L"foo"); // expected-warning{{conversion from string literal to 'wchar_t *' is deprecated}}
   double* dp1 = l("foo");
 }
 
@@ -79,7 +79,7 @@ class E;
 void test_n(E* e) {
   char ca[7];
   int* ip1 = n(ca);
-  int* ip2 = n("foo");
+  int* ip2 = n("foo"); // expected-warning{{conversion from string literal to 'char *' is deprecated}}
 
   float fa[7];
   double* dp1 = n(fa);

clang/test/SemaCXX/type-convert-construct.cpp

@@ -11,7 +11,7 @@ void f() {
   int *p;
   bool v6 = T(0) == p;
   char *str;
-  str = "a string";
+  str = "a string"; // expected-warning{{conversion from string literal to 'char *' is deprecated}}
   wchar_t *wstr;
-  wstr = L"a wide string";
+  wstr = L"a wide string"; // expected-warning{{conversion from string literal to 'wchar_t *' is deprecated}}
 }