Add assertions to verify that we are not trying to instantiate a
nontemplate in Sema::InstantiateTemplateDecl.

This should make the issue in PR10026 more visible, although it's not
going to fix it because something is violating this precondition.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132208 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed