Objective-C. Make diagnostics and fix-its consistent

when diagnosing casting of a cstring literal to
NSString in default and -fobjc-arc mode. 
// rdar://14106083

llvm-svn: 197515

2 files changed, 23 insertions, 11 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index e4a6102b067..0597a998c47 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -10587,22 +10587,23 @@ ExprResult Sema::ActOnGNUNullExpr(SourceLocation TokenLoc) {
   return Owned(new (Context) GNUNullExpr(Ty, TokenLoc));
 }
 
-static void MakeObjCStringLiteralFixItHint(Sema& SemaRef, QualType DstType,
-                                           Expr *SrcExpr, FixItHint &Hint,
-                                           bool &IsNSString) {
-  if (!SemaRef.getLangOpts().ObjC1)
-    return;
+StringLiteral *
+Sema::ConversionToObjCStringLiteralCheck(QualType DstType,
+                                     Expr *SrcExpr, FixItHint &Hint,
+                                     bool &IsNSString) {
+  if (!getLangOpts().ObjC1)
+    return 0;
 
   const ObjCObjectPointerType *PT = DstType->getAs<ObjCObjectPointerType>();
   if (!PT)
-    return;
+    return 0;
 
   // Check if the destination is of type 'id'.
   if (!PT->isObjCIdType()) {
     // Check if the destination is the 'NSString' interface.
     const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
     if (!ID || !ID->getIdentifier()->isStr("NSString"))
-      return;
+      return 0;
     IsNSString = true;
   }
 
@@ -10616,9 +10617,9 @@ static void MakeObjCStringLiteralFixItHint(Sema& SemaRef, QualType DstType,
 
   StringLiteral *SL = dyn_cast<StringLiteral>(SrcExpr);
   if (!SL || !SL->isAscii())
-    return;
-
+    return 0;
   Hint = FixItHint::CreateInsertion(SL->getLocStart(), "@");
+  return SL;
 }
 
 bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
@@ -10655,7 +10656,7 @@ bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
     MayHaveConvFixit = true;
     break;
   case IncompatiblePointer:
-    MakeObjCStringLiteralFixItHint(*this, DstType, SrcExpr, Hint, IsNSString);
+    ConversionToObjCStringLiteralCheck(DstType, SrcExpr, Hint, IsNSString);
       DiagKind =
         (Action == AA_Passing_CFAudited ?
           diag::err_arc_typecheck_convert_incompatible_pointer :
@@ -10670,7 +10671,7 @@ bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
       DstType = DstType.getUnqualifiedType();
     }
     else if (IsNSString && !Hint.isNull())
-      DiagKind = diag::warn_missing_atsign_prefix;
+      DiagKind = diag::err_missing_atsign_prefix;
     MayHaveConvFixit = true;
     break;
   case IncompatiblePointerSign:
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 905c080e47d..f312839a9d2 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -3612,6 +3612,17 @@ Sema::CheckObjCARCConversion(SourceRange castRange, QualType castType,
       CCK != CCK_ImplicitConversion)
     return ACR_unbridged;
 
+  // Do not issue bridge cast" diagnostic when implicit casting a cstring
+  // to 'NSString *'. Let caller issue a normal mismatched diagnostic with
+  // suitable fix-it.
+  if (castACTC == ACTC_retainable && exprACTC == ACTC_none) {
+    bool IsNSString = false;
+    FixItHint Hint;
+    if (ConversionToObjCStringLiteralCheck(
+          castType, castExpr, Hint, IsNSString) && IsNSString)
+      return ACR_okay;
+  }
+  
   // Do not issue "bridge cast" diagnostic when implicit casting
   // a retainable object to a CF type parameter belonging to an audited
   // CF API function. Let caller issue a normal type mismatched diagnostic