re PR c++/52269 ([C++11] Body of constexpr function templates instantiated too…

re PR c++/52269 ([C++11] Body of constexpr function templates instantiated too eagerly in unevaluated operands)

	PR c++/52269
	* g++.dg/cpp0x/constexpr-decltype4.C: New test.

From-SVN: r272083

gcc/testsuite/ChangeLog

+2019-06-08  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/52269
+	* g++.dg/cpp0x/constexpr-decltype4.C: New test.
+
 2019-06-08  Thomas Koenig  <tkoenig@gcc.gnu.org>
-	Tomáš Trnka  <trnka@scm.com>
+	    Tomáš Trnka  <trnka@scm.com>
 
 	PR fortran/90744
 	* gfortran.dg/deferred_character_33.f90: New test.

gcc/testsuite/g++.dg/cpp0x/constexpr-decltype4.C

+// PR c++/52269
+// { dg-do compile { target c++11 } }
+
+template<typename T>
+int f(T x)
+{
+  return x.get();
+}
+
+// O.K. The body of `f' is not required.
+decltype(f(0)) a;
+
+template<typename T>
+constexpr int g(T x)
+{
+  return x.get();
+}
+
+// Seems to instantiate the body of `g'
+// and results in an error.
+decltype(g(0)) b;