The attached patch fixes this by adding code to match a default character
expression if the left paren is first matched on a READ statement.  If the
expression is matched the dt-format is set and processing continues.  Otherwise
execution drops through to match a control list as usual.

Regression tested on x86-64-linux. Test case attached.

OK for trunk?

Regards,

Jerry

2016-05-30  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR fortran/52393
	* io.c (match_io): For READ, try to match a default character
	expression. If found, set the dt format expression to this,
	otherwise go back and try control list.