From 2c4a7501eef0db6198e896b17be8333def044c85 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 23 Apr 2010 02:08:13 +0000
Subject: [PATCH] When parsing a cast-expression that starts with a scope
 annotation, try to annotate as a type first to determine whether we have a
 functional-style cast. Patch by Eli Friedman, fixes PR6830.

llvm-svn: 102161
---
 clang/lib/Parse/ParseExpr.cpp              |  8 ++++++++
 clang/test/SemaCXX/qualified-id-lookup.cpp | 22 ++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 588825b01ca4..b9e632a1846e 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -788,6 +788,14 @@ Parser::OwningExprResult Parser::ParseCastExpression(bool isUnaryExpression,
   }
 
   case tok::annot_cxxscope: { // [C++] id-expression: qualified-id
+    // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
+    // (We can end up in this situation after tentative parsing.)
+    if (TryAnnotateTypeOrScopeToken())
+      return ExprError();
+    if (!Tok.is(tok::annot_cxxscope))
+      return ParseCastExpression(isUnaryExpression, isAddressOfOperand,
+                                 NotCastExpr, TypeOfCast);
+
     Token Next = NextToken();
     if (Next.is(tok::annot_template_id)) {
       TemplateIdAnnotation *TemplateId
diff --git a/clang/test/SemaCXX/qualified-id-lookup.cpp b/clang/test/SemaCXX/qualified-id-lookup.cpp
index abde62efceae..dfb059aa36ad 100644
--- a/clang/test/SemaCXX/qualified-id-lookup.cpp
+++ b/clang/test/SemaCXX/qualified-id-lookup.cpp
@@ -124,3 +124,25 @@ namespace test1 {
 
   template class ClassChecker<int>;  
 }
+
+namespace PR6830 {
+  namespace foo {
+
+    class X {
+    public:
+      X() {}
+    };
+
+  }  // namespace foo
+
+  class Z {
+  public:
+    explicit Z(const foo::X& x) {}
+
+    void Work() {}
+  };
+
+  void Test() {
+    Z(foo::X()).Work();
+  }
+}
-- 
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