[gcc r10-11235] d: Fix ICE on explicit immutable struct import [PR108877]

[Iain Buclaw <ibuclaw@gcc.gnu.org>]

https://gcc.gnu.org/g:c90e68bffa37edd655dd2f5d14bb7b213c9e2431

commit r10-11235-gc90e68bffa37edd655dd2f5d14bb7b213c9e2431
Author: Iain Buclaw <ibuclaw@gdcproject.org>
Date:   Mon Feb 27 20:46:18 2023 +0100

    d: Fix ICE on explicit immutable struct import [PR108877]
    
    Const and immutable types are built as variants of the type they are
    derived from, and TYPE_STUB_DECL is not set for these variants.
    
            PR d/108877
    
    gcc/d/ChangeLog:
    
            * imports.cc (ImportVisitor::visit (EnumDeclaration *)): Call
            make_import on TYPE_MAIN_VARIANT.
            (ImportVisitor::visit (AggregateDeclaration *)): Likewise.
            (ImportVisitor::visit (ClassDeclaration *)): Likewise.
    
    gcc/testsuite/ChangeLog:
    
            * gdc.dg/imports/pr108877a.d: New test.
            * gdc.dg/pr108877.d: New test.
    
    (cherry picked from commit ce1cea3e22f58bbddde017f8a92e59bae8892339)

Diff:
---
 gcc/d/imports.cc                         | 8 +++++++-
 gcc/testsuite/gdc.dg/imports/pr108877a.d | 6 ++++++
 gcc/testsuite/gdc.dg/pr108877.d          | 9 +++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/gcc/d/imports.cc b/gcc/d/imports.cc
index e72f1ea00ac..7852519bf6d 100644
--- a/gcc/d/imports.cc
+++ b/gcc/d/imports.cc
@@ -97,12 +97,17 @@ public:
     tree type = build_ctype (d->type);
     /* Not all kinds of D enums create a TYPE_DECL.  */
     if (TREE_CODE (type) == ENUMERAL_TYPE)
-      d->isym = this->make_import (TYPE_STUB_DECL (type));
+      {
+	type = TYPE_MAIN_VARIANT (type);
+	d->isym = this->make_import (TYPE_STUB_DECL (type));
+      }
+
   }
 
   void visit (AggregateDeclaration *d)
   {
     tree type = build_ctype (d->type);
+    type = TYPE_MAIN_VARIANT (type);
     d->isym = this->make_import (TYPE_STUB_DECL (type));
   }
 
@@ -110,6 +115,7 @@ public:
   {
     /* Want the RECORD_TYPE, not POINTER_TYPE.  */
     tree type = TREE_TYPE (build_ctype (d->type));
+    type = TYPE_MAIN_VARIANT (type);
     d->isym = this->make_import (TYPE_STUB_DECL (type));
   }
 
diff --git a/gcc/testsuite/gdc.dg/imports/pr108877a.d b/gcc/testsuite/gdc.dg/imports/pr108877a.d
new file mode 100644
index 00000000000..a23c78ddf84
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/imports/pr108877a.d
@@ -0,0 +1,6 @@
+immutable struct ImmutableS { }
+const struct ConstS { }
+immutable class ImmutableC { }
+const class ConstC { }
+immutable enum ImmutableE { _ }
+const enum ConstE { _ }
diff --git a/gcc/testsuite/gdc.dg/pr108877.d b/gcc/testsuite/gdc.dg/pr108877.d
new file mode 100644
index 00000000000..710551f3f9a
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr108877.d
@@ -0,0 +1,9 @@
+// { dg-options "-I $srcdir/gdc.dg" }
+// { dg-do compile }
+import imports.pr108877a :
+    ImmutableS,
+    ConstS,
+    ImmutableC,
+    ConstC,
+    ImmutableE,
+    ConstE;