c++: template partial instantiation mismatch [PR 99528]

This turned out to be an existing problem, which had been hidden by
other bugs.  Templated members of templated classes can end up
instantiating the template itself, and we were not handling the
mergeableness of that correctly.

	PR c++/99528
	gcc/cp/
	* module.cc (enum merge_kind): Delete MK_type_tmpl_spec,
	MK_decl_tmpl_spec.
	(trees_in::decl_value): Adjust add_mergeable_specialization call.
	(trees_out::get_merge_kind): Adjust detecting a partial template
	instantiation.
	(trees_out::key_mergeable): Adjust handling same.
	(trees_in::key_mergeabvle): Likewise.
	gcc/testsuite/
	* g++.dg/modules/pr99528.h: New.
	* g++.dg/modules/pr99528_a.H: New.
	* g++.dg/modules/pr99528_b.H: New.
	* g++.dg/modules/pr99528_c.C: New.

5 files changed, 35 insertions, 45 deletions

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index db5fa90..03359db 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -2783,11 +2783,7 @@ enum merge_kind
   MK_tmpl_tmpl_mask = 0x1, /* We want TEMPLATE_DECL.  */
 
   MK_type_spec = MK_template_mask,
-  MK_type_tmpl_spec = MK_type_spec | MK_tmpl_tmpl_mask,
-
   MK_decl_spec = MK_template_mask | MK_tmpl_decl_mask,
-  MK_decl_tmpl_spec = MK_decl_spec | MK_tmpl_tmpl_mask,
-
   MK_alias_spec = MK_decl_spec | MK_tmpl_alias_mask,
 
   MK_hwm = 0x20
@@ -8062,10 +8058,10 @@ trees_in::decl_value ()
 	{
 	  /* Add to specialization tables now that constraints etc are
 	     added.  */
-	  bool is_decl = (mk & MK_template_mask) && (mk & MK_tmpl_decl_mask);
+	  bool is_type = mk == MK_partial || !(mk & MK_tmpl_decl_mask);
 
-	  spec.spec = is_decl ? inner : type;
-	  add_mergeable_specialization (is_decl, &spec, decl, spec_flags);
+	  spec.spec = is_type ? type : mk & MK_tmpl_tmpl_mask ? inner : decl;
+	  add_mergeable_specialization (!is_type, &spec, decl, spec_flags);
 	}
 
       if (TREE_CODE (decl) == INTEGER_CST && !TREE_OVERFLOW (decl))
@@ -10229,7 +10225,6 @@ trees_out::get_merge_kind (tree decl, depset *dep)
     case depset::EK_SPECIALIZATION:
       {
 	gcc_checking_assert (dep->is_special ());
-	spec_entry *entry = reinterpret_cast <spec_entry *> (dep->deps[0]);
 
 	if (TREE_CODE (DECL_CONTEXT (decl)) == FUNCTION_DECL)
 	  /* An block-scope classes of templates are themselves
@@ -10247,13 +10242,8 @@ trees_out::get_merge_kind (tree decl, depset *dep)
 
 	if (TREE_CODE (decl) == TEMPLATE_DECL)
 	  {
-	    tree res = DECL_TEMPLATE_RESULT (decl);
-	    if (!(mk & MK_tmpl_decl_mask))
-	      res = TREE_TYPE (res);
-
-	    if (res == entry->spec)
-	      /* We check we can get back to the template during
-		 streaming.  */
+	    spec_entry *entry = reinterpret_cast <spec_entry *> (dep->deps[0]);
+	    if (TREE_CODE (entry->spec) != TEMPLATE_DECL)
 	      mk = merge_kind (mk | MK_tmpl_tmpl_mask);
 	  }
       }
@@ -10362,15 +10352,14 @@ trees_out::key_mergeable (int tag, merge_kind mk, tree decl, tree inner,
 		gcc_assert (match_mergeable_specialization (false, entry)
 			    == TREE_TYPE (existing));
 	      else if (mk & MK_tmpl_tmpl_mask)
-		if (tree ti = DECL_TEMPLATE_INFO (existing))
-		  existing = TI_TEMPLATE (ti);
+		existing = DECL_TI_TEMPLATE (existing);
 	    }
 	  else
 	    {
-	      if (!(mk & MK_tmpl_tmpl_mask))
+	      if (mk & MK_tmpl_tmpl_mask)
+		existing = CLASSTYPE_TI_TEMPLATE (existing);
+	      else
 		existing = TYPE_NAME (existing);
-	      else if (tree ti = CLASSTYPE_TEMPLATE_INFO (existing))
-		existing = TI_TEMPLATE (ti);
 	    }
 
 	  /* The walkabout should have found ourselves.  */
@@ -10677,13 +10666,6 @@ trees_in::key_mergeable (int tag, merge_kind mk, tree decl, tree inner,
       DECL_NAME (inner) = DECL_NAME (decl);
       DECL_CONTEXT (inner) = DECL_CONTEXT (decl);
 
-      spec.spec = decl;
-      if (mk & MK_tmpl_tmpl_mask)
-	{
-	  if (inner == decl)
-	    return error_mark_node;
-	  spec.spec = inner;
-	}
       tree constr = NULL_TREE;
       bool is_decl = mk & MK_tmpl_decl_mask;
       if (is_decl)
@@ -10694,13 +10676,10 @@ trees_in::key_mergeable (int tag, merge_kind mk, tree decl, tree inner,
 	      if (constr)
 		set_constraints (inner, constr);
 	    }
+	  spec.spec = (mk & MK_tmpl_tmpl_mask) ? inner : decl;
 	}
       else
-	{
-	  if (mk == MK_type_spec && inner != decl)
-	    return error_mark_node;
-	  spec.spec = type;
-	}
+	spec.spec = type;
       existing = match_mergeable_specialization (is_decl, &spec);
       if (constr)
 	/* We'll add these back later, if this is the new decl.  */
@@ -10712,24 +10691,15 @@ trees_in::key_mergeable (int tag, merge_kind mk, tree decl, tree inner,
 	{
 	  /* A declaration specialization.  */
 	  if (mk & MK_tmpl_tmpl_mask)
-	    if (tree ti = DECL_TEMPLATE_INFO (existing))
-	      {
-		tree tmpl = TI_TEMPLATE (ti);
-		if (DECL_TEMPLATE_RESULT (tmpl) == existing)
-		  existing = tmpl;
-	      }
+	    existing = DECL_TI_TEMPLATE (existing);
 	}
       else
 	{
 	  /* A type specialization.  */
-	  if (!(mk & MK_tmpl_tmpl_mask))
+	  if (mk & MK_tmpl_tmpl_mask)
+	    existing = CLASSTYPE_TI_TEMPLATE (existing);
+	  else
 	    existing = TYPE_NAME (existing);
-	  else if (tree ti = CLASSTYPE_TEMPLATE_INFO (existing))
-	    {
-	      tree tmpl = TI_TEMPLATE (ti);
-	      if (DECL_TEMPLATE_RESULT (tmpl) == TYPE_NAME (existing))
-		existing = tmpl;
-	    }
 	}
     }
   else if (mk == MK_unique)
diff --git a/gcc/testsuite/g++.dg/modules/pr99528.h b/gcc/testsuite/g++.dg/modules/pr99528.h
new file mode 100644
index 0000000..ea5d60f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99528.h
@@ -0,0 +1,9 @@
+template<typename _Tp>
+class new_allocator
+{
+public:
+  template<typename _Tp1>
+  new_allocator(const new_allocator<_Tp1>&) noexcept { }
+};
+
+extern template class new_allocator<char>;
diff --git a/gcc/testsuite/g++.dg/modules/pr99528_a.H b/gcc/testsuite/g++.dg/modules/pr99528_a.H
new file mode 100644
index 0000000..08f766b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99528_a.H
@@ -0,0 +1,4 @@
+// PR 99528, ICE with template/function mismatch
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+#include "pr99528.h"
diff --git a/gcc/testsuite/g++.dg/modules/pr99528_b.H b/gcc/testsuite/g++.dg/modules/pr99528_b.H
new file mode 100644
index 0000000..48c4b4d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99528_b.H
@@ -0,0 +1,4 @@
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+#include "pr99528.h"
+
diff --git a/gcc/testsuite/g++.dg/modules/pr99528_c.C b/gcc/testsuite/g++.dg/modules/pr99528_c.C
new file mode 100644
index 0000000..ca8d867
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/pr99528_c.C
@@ -0,0 +1,3 @@
+// { dg-additional-options {-fmodules-ts -fno-module-lazy} }
+import "pr99528_a.H";
+import "pr99528_b.H";