[COMMITTED] ada: Fix internal error on call with parameter of predicated subtype

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

From: Eric Botcazou <ebotcazou@adacore.com>

The problem is that the predicated subtype does not inherit all the required
attributes of a string subtype with a static predicate.

gcc/ada/

	* sem_ch3.adb (Analyze_Subtype_Declaration): Remove a short-circuit
	for subtypes without aspects when it comes to predicates.
	* sem_util.adb (Inherit_Predicate_Flags): Deal with private subtypes
	whose full view is an Itype.

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

---
 gcc/ada/sem_ch3.adb  | 11 ++---------
 gcc/ada/sem_util.adb |  7 ++++++-
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
index 33d8f116bc2..a6bc8c95cd2 100644
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -6032,17 +6032,10 @@ package body Sem_Ch3 is
       --  If this is a subtype declaration for an actual in an instance,
       --  inherit static and dynamic predicates if any.
 
-      --  If declaration has no aspect specifications, inherit predicate
-      --  info as well. Unclear how to handle the case of both specified
-      --  and inherited predicates ??? Other inherited aspects, such as
-      --  invariants, should be OK, but the combination with later pragmas
-      --  may also require special merging.
-
       if Has_Predicates (T)
         and then Present (Predicate_Function (T))
-        and then
-          ((In_Instance and then not Comes_From_Source (N))
-             or else No (Aspect_Specifications (N)))
+        and then In_Instance
+        and then not Comes_From_Source (N)
       then
          --  Inherit Subprograms_For_Type from the full view, if present
 
diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index 791fa7bc12e..9cff9e1be16 100644
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -14531,11 +14531,16 @@ package body Sem_Util is
       --  A named subtype does not inherit the predicate function of its
       --  parent but an itype declared for a loop index needs the discrete
       --  predicate information of its parent to execute the loop properly.
+      --  Moreover, a named private subtype whose full view is an itype also
+      --  needs to inherit a predicate function because it will not be frozen.
       --  A non-discrete type may has a static predicate (for example True)
       --  but has no static_discrete_predicate.
 
       if not Only_Flags
-        and then Is_Itype (Subt)
+        and then (Is_Itype (Subt)
+                   or else (Ekind (Subt) = E_Private_Subtype
+                             and then Present (Full_View (Subt))
+                             and then Is_Itype (Full_View (Subt))))
         and then Present (Predicate_Function (Par))
       then
          Set_Subprograms_For_Type (Subt, Subprograms_For_Type (Par));
-- 
2.43.0