[PATCH] c++ modules: verify_type failure with typedef enum [PR106848]

[Patrick Palka <ppalka@redhat.com>]

Here during stream in we end up having created a type variant for the enum
before we read the enum's definition, and thus the variant inherited stale
TYPE_VALUES and TYPE_MIN/MAX_VALUES, which leads to an ICE (with -g).  The
stale variant got created from set_underlying_type during earlier stream in
of the (redundant) typedef for the enum.

This patch works around this by setting TYPE_VALUES and TYPE_MIN/MAX_VALUES
for all variants when reading in an enum definition.  Does this look like
the right approach?  Or perhaps we need to arrange that we read the enum
definition before reading in the typedef decl?  Note that seems to be an
issue only when the typedef name and enum names are the same (thus the
typedef is redundant), otherwise we seem to read the enum definition first
as desired.

	PR c++/106848

gcc/cp/ChangeLog:

	* module.cc (trees_in::read_enum_def): Set the TYPE_VALUES,
	TYPE_MIN_VALUE and TYPE_MAX_VALUE of all type variants.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/enum-9_a.H: New test.
	* g++.dg/modules/enum-9_b.C: New test.
---
 gcc/cp/module.cc                        | 9 ++++++---
 gcc/testsuite/g++.dg/modules/enum-9_a.H | 5 +++++
 gcc/testsuite/g++.dg/modules/enum-9_b.C | 6 ++++++
 3 files changed, 17 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/modules/enum-9_a.H
 create mode 100644 gcc/testsuite/g++.dg/modules/enum-9_b.C

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 7ffeefa7c1f..97fb80bcd44 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -12303,9 +12303,12 @@ trees_in::read_enum_def (tree defn, tree maybe_template)
 
   if (installing)
     {
-      TYPE_VALUES (type) = values;
-      TYPE_MIN_VALUE (type) = min;
-      TYPE_MAX_VALUE (type) = max;
+      for (tree t = type; t; t = TYPE_NEXT_VARIANT (t))
+	{
+	  TYPE_VALUES (t) = values;
+	  TYPE_MIN_VALUE (t) = min;
+	  TYPE_MAX_VALUE (t) = max;
+	}
 
       rest_of_type_compilation (type, DECL_NAMESPACE_SCOPE_P (defn));
     }
diff --git a/gcc/testsuite/g++.dg/modules/enum-9_a.H b/gcc/testsuite/g++.dg/modules/enum-9_a.H
new file mode 100644
index 00000000000..fb7d10ad3b6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/enum-9_a.H
@@ -0,0 +1,5 @@
+// PR c++/106848
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+
+typedef enum memory_order { memory_order_seq_cst } memory_order;
diff --git a/gcc/testsuite/g++.dg/modules/enum-9_b.C b/gcc/testsuite/g++.dg/modules/enum-9_b.C
new file mode 100644
index 00000000000..63e81675d0a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/enum-9_b.C
@@ -0,0 +1,6 @@
+// PR c++/106848
+// { dg-additional-options "-fmodules-ts -g" }
+
+import "enum-9_a.H";
+
+memory_order x = memory_order_seq_cst;
-- 
2.38.0.68.ge85701b4af