c++: duplicate const static members [PR 99283]

This is the bug that keeps on giving.  Reducing it has been successful
at hitting other defects. In this case, some more specialization hash
table fun, plus an issue with reading in a definition of a duplicated
declaration.  At least I discovered a null context check is no longer
needed.

	PR c++/99283
	gcc/cp/
	* module.cc (dumper::operator): Make less brittle.
	(trees_out::core_bools): VAR_DECLs always have a context.
	(trees_out::key_mergeable): Use same_type_p for asserting.
	(trees_in::read_var_def): Propagate
	DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P.
	gcc/testsuite/
	* g++.dg/modules/pr99283-5.h: New.
	* g++.dg/modules/pr99283-5_a.H: New.
	* g++.dg/modules/pr99283-5_b.H: New.
	* g++.dg/modules/pr99283-5_c.C: New.

5 files changed, 54 insertions, 8 deletions

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 8a1cfbd..fab6b57 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -4325,8 +4325,8 @@ dumper::operator () (const char *format, ...)
 	case 'N': /* Name.  */
 	  {
 	    tree t = va_arg (args, tree);
-	    if (t && TREE_CODE (t) == OVERLOAD)
-	      t = OVL_FIRST (t);
+	    while (t && TREE_CODE (t) == OVERLOAD)
+	      t = OVL_FUNCTION (t);
 	    fputc ('\'', dumps->stream);
 	    dumps->nested_name (t);
 	    fputc ('\'', dumps->stream);
@@ -5206,8 +5206,7 @@ trees_out::core_bools (tree t)
       else if (code == VAR_DECL)
 	{
 	  /* This is DECL_INITIALIZED_P.  */
-	  if (DECL_CONTEXT (t)
-	      && TREE_CODE (DECL_CONTEXT (t)) != FUNCTION_DECL)
+	  if (TREE_CODE (DECL_CONTEXT (t)) != FUNCTION_DECL)
 	    /* We'll set this when reading the definition.  */
 	    flag_1 = false;
 	}
@@ -10331,8 +10330,8 @@ trees_out::key_mergeable (int tag, merge_kind mk, tree decl, tree inner,
 	      if (mk & MK_tmpl_alias_mask)
 		/* It should be in both tables.  */
 		gcc_checking_assert
-		  (match_mergeable_specialization (false, entry)
-		   == TREE_TYPE (existing));
+		  (same_type_p (match_mergeable_specialization (false, entry),
+				TREE_TYPE (existing)));
 	      if (mk & MK_tmpl_tmpl_mask)
 		existing = DECL_TI_TEMPLATE (existing);
 	    }
@@ -10345,7 +10344,10 @@ trees_out::key_mergeable (int tag, merge_kind mk, tree decl, tree inner,
 	    }
 
 	  /* The walkabout should have found ourselves.  */
-	  gcc_checking_assert (existing == decl);
+	  gcc_checking_assert (TREE_CODE (decl) == TYPE_DECL
+			       ? same_type_p (TREE_TYPE (decl),
+					      TREE_TYPE (existing))
+			       : existing == decl);
 	}
     }
   else if (mk != MK_unique)
@@ -11513,7 +11515,11 @@ trees_in::read_var_def (tree decl, tree maybe_template)
       if (DECL_EXTERNAL (decl))
 	DECL_NOT_REALLY_EXTERN (decl) = true;
       if (VAR_P (decl))
-	DECL_INITIALIZED_P (decl) = true;
+	{
+	  DECL_INITIALIZED_P (decl) = true;
+	  if (maybe_dup && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (maybe_dup))
+	    DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = true;
+	}
       DECL_INITIAL (decl) = init;
       if (!dyn_init)
 	;
diff --git a/gcc/testsuite/g++.dg/modules/pr99283-5.h b/gcc/testsuite/g++.dg/modules/pr99283-5.h
new file mode 100644
index 0000000..3c3421f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99283-5.h
@@ -0,0 +1,9 @@
+template<typename _Value>
+struct __traits
+{
+  static const int __digits = 8;
+  static const _Value __min = 0;
+};
+
+template<typename _Value>
+const _Value __traits<_Value>::__min;
diff --git a/gcc/testsuite/g++.dg/modules/pr99283-5_a.H b/gcc/testsuite/g++.dg/modules/pr99283-5_a.H
new file mode 100644
index 0000000..6406dfe
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99283-5_a.H
@@ -0,0 +1,14 @@
+// PR 99283 part 5
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+
+#include "pr99283-5.h"
+
+template<typename _Value>
+const int __traits<_Value>::__digits;
+
+template<typename _Tp>
+void Foo ()
+{
+  __traits<unsigned>::__digits;
+}
diff --git a/gcc/testsuite/g++.dg/modules/pr99283-5_b.H b/gcc/testsuite/g++.dg/modules/pr99283-5_b.H
new file mode 100644
index 0000000..3f4237e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99283-5_b.H
@@ -0,0 +1,12 @@
+// { dg-additional-options {-fmodule-header -fno-module-lazy} }
+// { dg-module-cmi {} }
+
+#include "pr99283-5.h"
+
+template<typename _Tp>
+void Bar ()
+{
+  __traits<unsigned>::__min;
+}
+
+import  "pr99283-5_a.H";
diff --git a/gcc/testsuite/g++.dg/modules/pr99283-5_c.C b/gcc/testsuite/g++.dg/modules/pr99283-5_c.C
new file mode 100644
index 0000000..cc7e795
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99283-5_c.C
@@ -0,0 +1,5 @@
+// { dg-additional-options {-fmodules-ts -fno-module-lazy} }
+
+import  "pr99283-5_b.H";
+
+static_assert(!__traits<unsigned>::__min);