Remove default arguments from TryImplicitConversion and fix a bug found in the process.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@80258 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 52010ab..b1364a9 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -1929,7 +1929,9 @@
                        /*AllowExplicit=*/false, ForceRValue);
     return ICS;
   } else {
-    return TryImplicitConversion(From, ToType, SuppressUserConversions,
+    return TryImplicitConversion(From, ToType, 
+                                 SuppressUserConversions,
+                                 /*AllowExplicit=*/false,
                                  ForceRValue);
   }
 }
@@ -2064,7 +2066,11 @@
 /// TryContextuallyConvertToBool - Attempt to contextually convert the
 /// expression From to bool (C++0x [conv]p3).
 ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) {
-  return TryImplicitConversion(From, Context.BoolTy, false, true);
+  return TryImplicitConversion(From, Context.BoolTy, 
+                               // FIXME: Are these flags correct?
+                               /*SuppressUserConversions=*/false,
+                               /*AllowExplicit=*/true, 
+                               /*ForceRValue=*/false);
 }
 
 /// PerformContextuallyConvertToBool - Perform a contextual conversion