This was failing because uses_template_parms didn't recognize LAMBDA_EXPR as
a kind of expression.  Instead of trying to enumerate all the different
varieties of expression and then aborting if what's left isn't
error_mark_node, let's handle error_mark_node and then assume anything else
is an expression.

	* pt.c (uses_template_parms): Don't try to enumerate all the
	expression cases.