Implement C++ core issue 974, which permits default arguments for

lambda expressions. Because these issue was pulled back from Ready
status at the Kona meeting, we still emit an ExtWarn when using
default arguments for lambda expressions.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150519 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 53 insertions, 2 deletions

diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/default-arguments.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/default-arguments.cpp
new file mode 100644
index 0000000000..5dac886d4d
--- /dev/null
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/default-arguments.cpp
@@ -0,0 +1,50 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 %s -Wno-lambda-extensions -verify
+
+void defargs() {
+  auto l1 = [](int i, int j = 17, int k = 18) { return i + j + k; };
+  int i1 = l1(1);
+  int i2 = l1(1, 2);
+  int i3 = l1(1, 2, 3);
+}
+
+
+void defargs_errors() {
+  auto l1 = [](int i, 
+               int j = 17, 
+               int k) { }; // expected-error{{missing default argument on parameter 'k'}}
+
+  auto l2 = [](int i, int j = i) {}; // expected-error{{default argument references parameter 'i'}}
+
+  int foo;
+  auto l3 = [](int i = foo) {}; // expected-error{{default argument references local variable 'foo' of enclosing function}}
+}
+
+struct NonPOD {
+  NonPOD();
+  NonPOD(const NonPOD&);
+  ~NonPOD();
+};
+
+struct NoDefaultCtor {
+  NoDefaultCtor(const NoDefaultCtor&); // expected-note{{candidate constructor}}
+  ~NoDefaultCtor();
+};
+
+template<typename T>
+void defargs_in_template_unused(T t) {
+  auto l1 = [](const T& value = T()) { };
+  l1(t);
+}
+
+template void defargs_in_template_unused(NonPOD);
+template void defargs_in_template_unused(NoDefaultCtor);
+
+template<typename T>
+void defargs_in_template_used() {
+  auto l1 = [](const T& value = T()) { }; // expected-error{{no matching constructor for initialization of 'NoDefaultCtor'}}
+  l1(); // expected-note{{in instantiation of default function argument expression for 'operator()<NoDefaultCtor>' required here}}
+}
+
+template void defargs_in_template_used<NonPOD>();
+template void defargs_in_template_used<NoDefaultCtor>(); // expected-note{{in instantiation of function template specialization}}
+
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
index 581dbca309..a67b5c01fd 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
@@ -38,9 +38,10 @@ void test_quals() {
 
 // Default arguments (8.3.6) shall not be specified in the
 // parameter-declaration-clause of a lambda- declarator.
+// Note: Removed by core issue 974.
 int test_default_args() {
-  return [](int i = 5,  // expected-error{{default arguments can only be specified for parameters in a function declaration}}
-            int j = 17) { return i+j;}(5, 6); // expected-error{{default arguments can only be specified for parameters in a function declaration}}
+  return [](int i = 5,  // expected-warning{{C++11 forbids default arguments for lambda expressions}}
+            int j = 17) { return i+j;}(5, 6);
 }
 
 // Any exception-specification specified on a lambda-expression