Introduce support for template instantiation of lambda

expressions. This is mostly a simple refact, splitting the main "start
a lambda expression" function into smaller chunks that are driven
either from the parser (Sema::ActOnLambdaExpr) or during AST
transformation (TreeTransform::TransformLambdaExpr). A few minor
interesting points:

  - Added new entry points for TreeTransform, so that we can
  explicitly establish the link between the lambda closure type in the
  template and the lambda closure type in the instantiation.
  - Added a bit into LambdaExpr specifying whether it had an explicit
  result type or not. We should have had this anyway.

This code is 'lightly' tested.

llvm-svn: 150417

1 files changed, 45 insertions, 0 deletions

diff --git a/clang/test/CXX/expr/expr.prim/expr.prim.lambda/templates.cpp b/clang/test/CXX/expr/expr.prim/expr.prim.lambda/templates.cpp
new file mode 100644
index 00000000000..4126dd96b97
--- /dev/null
+++ b/clang/test/CXX/expr/expr.prim/expr.prim.lambda/templates.cpp
@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -Winvalid-noreturn %s -verify
+
+template<typename T>
+void test_attributes() {
+  auto nrl = []() [[noreturn]] {}; // expected-warning{{function declared 'noreturn' should not return}}
+}
+
+template void test_attributes<int>(); // expected-note{{in instantiation of function}}
+
+template<typename T>
+void call_with_zero() {
+  [](T *ptr) -> T& { return *ptr; }(0);
+}
+
+template void call_with_zero<int>();
+
+template<typename T>
+T captures(T x, T y) {
+  auto lambda = [=, &y] () -> T {
+    T i = x;
+    return i + y;
+  };
+
+  return lambda();
+}
+
+struct X {
+  X(const X&);
+};
+
+X operator+(X, X);
+X operator-(X, X);
+
+template int captures(int, int);
+template X captures(X, X);
+
+template<typename T>
+int infer_result(T x, T y) {
+  auto lambda = [=](bool b) { return x + y; };
+  return lambda(true); // expected-error{{no viable conversion from 'X' to 'int'}}
+}
+
+template int infer_result(int, int);
+template int infer_result(X, X); // expected-note{{in instantiation of function template specialization 'infer_result<X>' requested here}}
+