cp:
	PR c++/21280
	* Make-lang.in (method.o): Add diagnostic.h
	* decl.c (start_preparsed_function): Use decl's location for file
	info.
	* decl2.c (cp_finish_file): Set input_location before synthesizing
	a function.
	(mark_used): When deferring a synthesized function, save current
	location.  Do not set function's location when actually
	synthesizing it.
	* method.c: #include diagnostic.h.
	(synthesize_method): Set the functions source location.  Show
	needed location if errors are emitted.
testsuite:
	PR c++/21280
	* g++.dg/opt/interface2.h: New.
	* g++.dg/opt/interface2.C: New.
	* g++.dg/init/ctor4.C: Adjust error lines.
	* g++.old-deja/g++.bob/inherit2.C: Likewise.
	* g++.old-deja/g++.bugs/900205_04.C: Likewise.
	* g++.old-deja/g++.jason/opeq3.C: Likewise.
	* g++.old-deja/g++.pt/assign1.C: Likewise.
	* g++.old-deja/g++.pt/crash20.C: Likewise.

From-SVN: r100500