Objective-C: patch to issue the conversion

warning when property-dot syntax is used
with -Wsign-conversion. // rdar://13855394


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181914 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaChecking.cpp

@@ -5133,7 +5133,13 @@ void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
     CheckImplicitConversion(S, E, T, CC);
 
   // Now continue drilling into this expression.
-
+  
+  if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) {
+    Expr *Result = POE->getResultExpr();
+    if (const OpaqueValueExpr *OVE = dyn_cast_or_null<OpaqueValueExpr>(Result))
+      return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC);
+  }
+  
   // Skip past explicit casts.
   if (isa<ExplicitCastExpr>(E)) {
     E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();

test/SemaObjC/sign-conversion.m

@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wsign-conversion %s
+// rdar://13855394
+
+@interface NSObject
+- new;
+@end
+
+@interface X : NSObject
+@property unsigned int uint;
+@end
+
+@implementation X 
+@synthesize uint;
+@end
+
+void foo() {
+    X *x = [X new];
+    signed int sint = -1;
+    [x setUint:sint];  // expected-warning {{implicit conversion changes signedness: 'int' to 'unsigned int'}}
+    x.uint = sint; // expected-warning {{implicit conversion changes signedness: 'int' to 'unsigned int'}}
+}