From 7a6182d48d63df5f2c8fbb112e0dc9c03c7e878a Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Sat, 24 Aug 2019 01:23:57 +0000
Subject: [PATCH] PR40674: fix assertion failure if a structured binding
 declaration has a tuple-like decomposition that produces value-dependent
 reference bindings.

llvm-svn: 369829
---
 clang/lib/Sema/SemaDeclCXX.cpp            | 3 ++-
 clang/test/CXX/dcl.decl/dcl.decomp/p3.cpp | 8 +++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 0f260ab6e91c..633a1667b2dc 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -1225,7 +1225,8 @@ static bool checkTupleLikeDecomposition(Sema &S,
     if (E.isInvalid())
       return true;
     RefVD->setInit(E.get());
-    RefVD->checkInitIsICE();
+    if (!E.get()->isValueDependent())
+      RefVD->checkInitIsICE();
 
     E = S.BuildDeclarationNameExpr(CXXScopeSpec(),
                                    DeclarationNameInfo(B->getDeclName(), Loc),
diff --git a/clang/test/CXX/dcl.decl/dcl.decomp/p3.cpp b/clang/test/CXX/dcl.decl/dcl.decomp/p3.cpp
index 9b030c1a2e13..ce5eefc6bfdb 100644
--- a/clang/test/CXX/dcl.decl/dcl.decomp/p3.cpp
+++ b/clang/test/CXX/dcl.decl/dcl.decomp/p3.cpp
@@ -127,7 +127,7 @@ void referenced_type() {
   using ConstInt3 = decltype(bcr2);
 }
 
-struct C { template<int> int get(); };
+struct C { template<int> int get() const; };
 template<> struct std::tuple_size<C> { static const int value = 1; };
 template<> struct std::tuple_element<0, C> { typedef int type; };
 
@@ -138,6 +138,12 @@ int member_get() {
   return c;
 }
 
+constexpr C c = C();
+template<const C *p> void dependent_binding_PR40674() {
+  const auto &[c] = *p;
+  (void)c;
+}
+
 struct D {
   // FIXME: Emit a note here explaining why this was ignored.
   template<int> struct get {};