Improve our handling of the -Wunused-variable warning in templates. In

particular, don't complain about unused variables that have dependent
type until instantiation time, so that we can look at the type of the
variable. Moreover, only complain about unused variables that have
neither a user-declared constructor nor a non-trivial destructor.

llvm-svn: 103362

1 files changed, 21 insertions, 0 deletions

diff --git a/clang/test/SemaTemplate/unused-variables.cpp b/clang/test/SemaTemplate/unused-variables.cpp
new file mode 100644
index 00000000000..1b9350b865d
--- /dev/null
+++ b/clang/test/SemaTemplate/unused-variables.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fsyntax-only -Wunused -verify %s
+
+struct X0 {
+  ~X0();
+};
+
+struct X1 { };
+
+template<typename T>
+void f() {
+  X0 x0;
+  X1 x1; // expected-warning{{unused variable 'x1'}}
+}
+
+template<typename T, typename U>
+void g() {
+  T t;
+  U u; // expected-warning{{unused variable 'u'}}
+}
+
+template void g<X0, X1>(); // expected-note{{in instantiation of}}