import std.path;

void main()
{
	globMatch("a.di", "*.d");
}

asserts with

core.exception.AssertError@std.path(2239): Assertion failure

The same happens when using fnmatch instead of globMatch. The problem is a wrong assert at the end of both functions:
    assert(ni >= path.length);

The wrong assert has been there before, but was actually never executed because it was built into the runtime library in release mode only. Now that the functions are templates, code generation moved to the user project, so the asserts can actually trigger.