[Ada] Missing check on illegal equality operation in subprogram

[Ada] Missing check on illegal equality operation in subprogram

In Ada2012 it is illegal to declare an equality operation on an untagged
type when the operation is primitive and the type is already frozem (see
RM 4.5.2 (9.8)). previously the test to detect this illegality only examined
declarations within a package. This patch covers the case where type and
operation are both declared within a subprogram body.

2018-07-17  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_ch6.adb (Check_Untagged_Equality): Extend check to operations
	declared in the same scope as the operand type, when that scope is a
	procedure.

gcc/testsuite/

	* gnat.dg/equal3.adb: New testcase.

From-SVN: r262788