From b3eb023bef514b684fcb374ae674c251e48514fd Mon Sep 17 00:00:00 2001
From: Hal Finkel <hfinkel@anl.gov>
Date: Sun, 27 Nov 2016 16:26:14 +0000
Subject: [PATCH] Adjust type-trait evaluation to properly handle
 Using(Shadow)Decls

Since r274049, for an inheriting constructor declaration, the name of the using
declaration (and using shadow declaration comes from the using declaration) is
the name of a derived class, not the base class (line 8225-8232 of
lib/Sema/SemaDeclCXX.cpp in https://reviews.llvm.org/rL274049). Because of
this, name-based lookup performed inside Sema::LookupConstructors returns not
only CXXConstructorDecls but also Using(Shadow)Decls, which results assertion
failure reported in PR29087.

Patch by Taewook Oh, thanks!

Differential Revision: https://reviews.llvm.org/D23765

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@287999 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaExprCXX.cpp       | 14 ++++++++++----
 test/SemaCXX/cxx11-crashes.cpp | 12 ++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 91cdb67f30..dfbbf01a51 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -4416,9 +4416,12 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
         // A template constructor is never a copy constructor.
         // FIXME: However, it may actually be selected at the actual overload
         // resolution point.
-        if (isa<FunctionTemplateDecl>(ND))
+        if (isa<FunctionTemplateDecl>(ND->getUnderlyingDecl()))
           continue;
-        const CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(ND);
+        // UsingDecl itself is not a constructor
+        if (isa<UsingDecl>(ND))
+          continue;
+        auto *Constructor = cast<CXXConstructorDecl>(ND->getUnderlyingDecl());
         if (Constructor->isCopyConstructor(FoundTQs)) {
           FoundConstructor = true;
           const FunctionProtoType *CPT
@@ -4452,9 +4455,12 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
       bool FoundConstructor = false;
       for (const auto *ND : Self.LookupConstructors(RD)) {
         // FIXME: In C++0x, a constructor template can be a default constructor.
-        if (isa<FunctionTemplateDecl>(ND))
+        if (isa<FunctionTemplateDecl>(ND->getUnderlyingDecl()))
+          continue;
+        // UsingDecl itself is not a constructor
+        if (isa<UsingDecl>(ND))
           continue;
-        const CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(ND);
+        auto *Constructor = cast<CXXConstructorDecl>(ND->getUnderlyingDecl());
         if (Constructor->isDefaultConstructor()) {
           FoundConstructor = true;
           const FunctionProtoType *CPT
diff --git a/test/SemaCXX/cxx11-crashes.cpp b/test/SemaCXX/cxx11-crashes.cpp
index 97c959454c..7c455eecd5 100644
--- a/test/SemaCXX/cxx11-crashes.cpp
+++ b/test/SemaCXX/cxx11-crashes.cpp
@@ -91,3 +91,15 @@ void test(int some_number) {  // expected-note {{'some_number' declared here}}
   Foo(lambda);
 }
 }
+
+namespace pr29091 {
+  struct X{ X(const X &x); };
+  struct Y: X { using X::X; };
+  bool foo() { return __has_nothrow_constructor(Y); }
+  bool bar() { return __has_nothrow_copy(Y); }
+
+  struct A { template <typename T> A(); };
+  struct B : A { using A::A; };
+  bool baz() { return __has_nothrow_constructor(B); }
+  bool qux() { return __has_nothrow_copy(B); }
+}
-- 
2.40.0