re PR c++/79435 (ICE on invalid C++ code (with member access into an incomplete type) on x86_64-linux-gnu: Segmentation fault)

	PR c++/79435
	* pt.c (type_dependent_expression_p): Check if the expression type
	is null.

	* g++.dg/cpp1y/pr79435.C: New.

From-SVN: r245334