A new conversion warning for when an Objective-C object literal is implicitly

cast into a boolean true value.  This warning will catch code like:

if (@0) {}
if (@"foo") {}

llvm-svn: 200356

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 0dffa53679e..ee0e6702e0f 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5358,6 +5358,13 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
       // prevented by a check in AnalyzeImplicitConversions().
       return DiagnoseImpCast(S, E, T, CC,
                              diag::warn_impcast_string_literal_to_bool);
+    if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) ||
+        isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) {
+      // This covers the literal expressions that evaluate to Objective-C
+      // objects.
+      return DiagnoseImpCast(S, E, T, CC,
+                             diag::warn_impcast_objective_c_literal_to_bool);
+    }
     if (Source->isFunctionType()) {
       // Warn on function to bool. Checks free functions and static member
       // functions. Weakly imported functions are excluded from the check,