3 files changed, 57 insertions, 11 deletions

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index c21cd3f65b..afc7fa8ea0 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1641,25 +1641,32 @@ const char *CastExpr::getCastKindName() const {
   llvm_unreachable("Unhandled cast kind!");
 }
 
+namespace {
+  Expr *skipImplicitTemporary(Expr *expr) {
+    // Skip through reference binding to temporary.
+    if (MaterializeTemporaryExpr *Materialize
+                                  = dyn_cast<MaterializeTemporaryExpr>(expr))
+      expr = Materialize->GetTemporaryExpr();
+
+    // Skip any temporary bindings; they're implicit.
+    if (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(expr))
+      expr = Binder->getSubExpr();
+
+    return expr;
+  }
+}
+
 Expr *CastExpr::getSubExprAsWritten() {
   Expr *SubExpr = nullptr;
   CastExpr *E = this;
   do {
-    SubExpr = E->getSubExpr();
+    SubExpr = skipImplicitTemporary(E->getSubExpr());
 
-    // Skip through reference binding to temporary.
-    if (MaterializeTemporaryExpr *Materialize 
-                                  = dyn_cast<MaterializeTemporaryExpr>(SubExpr))
-      SubExpr = Materialize->GetTemporaryExpr();
-        
-    // Skip any temporary bindings; they're implicit.
-    if (CXXBindTemporaryExpr *Binder = dyn_cast<CXXBindTemporaryExpr>(SubExpr))
-      SubExpr = Binder->getSubExpr();
-    
     // Conversions by constructor and conversion functions have a
     // subexpression describing the call; strip it off.
     if (E->getCastKind() == CK_ConstructorConversion)
-      SubExpr = cast<CXXConstructExpr>(SubExpr)->getArg(0);
+      SubExpr =
+        skipImplicitTemporary(cast<CXXConstructExpr>(SubExpr)->getArg(0));
     else if (E->getCastKind() == CK_UserDefinedConversion) {
       assert((isa<CXXMemberCallExpr>(SubExpr) ||
               isa<BlockExpr>(SubExpr)) &&
diff --git a/unittests/Tooling/CMakeLists.txt b/unittests/Tooling/CMakeLists.txt
index b5af99bdfd..8ed35480cb 100644
--- a/unittests/Tooling/CMakeLists.txt
+++ b/unittests/Tooling/CMakeLists.txt
@@ -11,6 +11,7 @@ if (MSVC)
 endif()
 
 add_clang_unittest(ToolingTests
+  CastExprTest.cpp
   CommentHandlerTest.cpp
   CompilationDatabaseTest.cpp
   FixItTest.cpp
diff --git a/unittests/Tooling/CastExprTest.cpp b/unittests/Tooling/CastExprTest.cpp
new file mode 100644
index 0000000000..5310c21254
--- /dev/null
+++ b/unittests/Tooling/CastExprTest.cpp
@@ -0,0 +1,38 @@
+//===- unittest/Tooling/CastExprTest.cpp ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestVisitor.h"
+
+using namespace clang;
+
+namespace {
+
+struct CastExprVisitor : TestVisitor<CastExprVisitor> {
+  std::function<void(ExplicitCastExpr *)> OnExplicitCast;
+
+  bool VisitExplicitCastExpr(ExplicitCastExpr *Expr) {
+    if (OnExplicitCast)
+      OnExplicitCast(Expr);
+    return true;
+  }
+};
+
+TEST(CastExprTest, GetSubExprAsWrittenThroughMaterializedTemporary) {
+    CastExprVisitor Visitor;
+    Visitor.OnExplicitCast = [](ExplicitCastExpr *Expr) {
+      auto Sub = Expr->getSubExprAsWritten();
+      EXPECT_TRUE(isa<DeclRefExpr>(Sub))
+        << "Expected DeclRefExpr, but saw " << Sub->getStmtClassName();
+    };
+    Visitor.runOver("struct S1 {};\n"
+                    "struct S2 { operator S1(); };\n"
+                    "S1 f(S2 s) { return static_cast<S1>(s); }\n");
+}
+
+}