PR19878: If a pack expansion appears within another pack expansion, correctly

deduce any packs that are expanded by both expansions.

llvm-svn: 209786

1 files changed, 20 insertions, 0 deletions

diff --git a/clang/test/SemaTemplate/pack-deduction.cpp b/clang/test/SemaTemplate/pack-deduction.cpp
new file mode 100644
index 00000000000..2d0a03f0fca
--- /dev/null
+++ b/clang/test/SemaTemplate/pack-deduction.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+
+template<typename ...T> struct X {};
+
+template<typename T, typename U> struct P {};
+
+namespace Nested {
+  template<typename ...T> int f1(X<T, T...>... a); // expected-note +{{conflicting types for parameter 'T'}}
+  template<typename ...T> int f2(P<X<T...>, T> ...a); // expected-note +{{conflicting types for parameter 'T'}}
+
+  int a1 = f1(X<int, int, double>(), X<double, int, double>());
+  int a2 = f1(X<int, int>());
+  int a3 = f1(X<int>(), X<double>()); // expected-error {{no matching}}
+  int a4 = f1(X<int, int>(), X<int>()); // expected-error {{no matching}}
+  int a5 = f1(X<int>(), X<int, int>()); // expected-error {{no matching}}
+  int a6 = f1(X<int, int, int>(), X<int, int, int>(), X<int, int, int, int>()); // expected-error {{no matching}}
+
+  int b1 = f2(P<X<int, double>, int>(), P<X<int, double>, double>());
+  int b2 = f2(P<X<int, double>, int>(), P<X<int, double>, double>(), P<X<int, double>, char>()); // expected-error {{no matching}}
+}