[COMMITTED] ada: Fix missing error on function call returning incomplete view

["Marc Poulhiès" <poulhies@adacore.com>]

From: Eric Botcazou <ebotcazou@adacore.com>

Testing for the presence of Non_Limited_View is not sufficient to detect
whether the nonlimited view has been analyzed because Build_Limited_Views
always sets the field on the limited view.  Instead the discriminant is
whether this nonlimited view is itself an incomplete type.

gcc/ada/

	* sem_ch4.adb (Analyze_Call): Adjust the test to detect the presence
	of an incomplete view of a type on a function call.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/sem_ch4.adb | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gcc/ada/sem_ch4.adb b/gcc/ada/sem_ch4.adb
index 02c59284994..b4b158a3ff4 100644
--- a/gcc/ada/sem_ch4.adb
+++ b/gcc/ada/sem_ch4.adb
@@ -1540,8 +1540,14 @@ package body Sem_Ch4 is
 
                Set_Etype (N, Full_View (Etype (N)));
 
+            --  If the call is within a thunk, the nonlimited view should be
+            --  analyzed eventually (see also Analyze_Return_Type).
+
             elsif From_Limited_With (Etype (N))
               and then Present (Non_Limited_View (Etype (N)))
+              and then
+                (Ekind (Non_Limited_View (Etype (N))) /= E_Incomplete_Type
+                  or else Is_Thunk (Current_Scope))
             then
                Set_Etype (N, Non_Limited_View (Etype (N)));
 
-- 
2.40.0