Remember the location of a variable template-id.

I noticed that tsubst of a TEMPLATE_ID_EXPR was losing the location
information from its EXPR_LOCATION.  Then I noticed that
cxx_eval_constant_expression was also throwing away location information for
variable references.

	* pt.c (tsubst_copy_and_build) [TEMPLATE_ID_EXPR]: Remember the
	location of a variable template-id.
	* constexpr.c (cxx_eval_constant_expression): Get expr location
	before stripping location wrappers.
	(non_const_var_error): Take location argument.

git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@278755 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 15 insertions, 1 deletions

diff --git a/gcc/testsuite/g++.dg/concepts/pr67595.C b/gcc/testsuite/g++.dg/concepts/pr67595.C
index 7199e0517d4..029ec7a1186 100644
--- a/gcc/testsuite/g++.dg/concepts/pr67595.C
+++ b/gcc/testsuite/g++.dg/concepts/pr67595.C
@@ -9,6 +9,6 @@ template <class X> bool input_iterator{weak_input_iterator<X>}; // { dg-warning
 template <class X> bool forward_iterator{input_iterator<X>};
 template <class X> bool bidirectional_iterator{forward_iterator<X>};
 template <class X>
-concept bool random_access_iterator{bidirectional_iterator<X>};
+concept bool random_access_iterator{bidirectional_iterator<X>}; // { dg-error "constant" }
 void fn1(random_access_iterator);
 int main() { fn1(0); }  // { dg-error "" }
diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ64.C b/gcc/testsuite/g++.dg/cpp1y/var-templ64.C
new file mode 100644
index 00000000000..4e2b43b1d07
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/var-templ64.C
@@ -0,0 +1,14 @@
+// { dg-do compile { target c++14 } }
+
+template <class T> T var = T();
+
+template <class T>
+void f()
+{
+  constexpr T i = var<T>;	// { dg-error "19:var" }
+}
+
+int main()
+{
+  f<int>();
+}