diff --git a/src/func_def.c b/src/func_def.c
index c28d7e0519..0e954ae248 100644
--- a/src/func_def.c
+++ b/src/func_def.c
@@ -371,6 +371,16 @@ indicated routine has just been processed.
   a_boolean  needed = FALSE;
   a_type_ptr class_type = parent_class_of(routine);
 
+#if IA64_ABI && ABI_COMPATIBILITY_VERSION >= 410
+  if (is_unspecialized_template_class(class_type) &&
+      class_type->variant.class_struct_union.do_not_instantiate &&
+      !class_type->variant.class_struct_union.explicitly_instantiated &&
+      class_type->source_corresp.name_linkage == nlk_cplusplus_external &&
+      !class_type_supp(class_type)->named_in_inline_template_directive) {
+    /* Lowering suppresses this specialization's virtual function table. */
+  } else
+#endif /* IA64_ABI && ABI_COMPATIBILITY_VERSION >= 410 */
+  /* Do not insert code here. */
   if (class_type->variant.class_struct_union.
                              any_virtual_functions_including_in_base_classes) {
     if (routine->special_kind == (a_special_function_kind)sfk_constructor ||
diff --git a/src/pending_changes/gh-431.txt b/src/pending_changes/gh-431.txt
new file mode 100644
index 0000000000..3c82314d3a
--- /dev/null
+++ b/src/pending_changes/gh-431.txt
@@ -0,0 +1,18 @@
+[GH #431]
+Virtual function instantiation for suppressed class template specializations
+
+Previously, in IA-64 ABI configurations with ABI_COMPATIBILITY_VERSION >= 410,
+defining an inline member function of a class template specialization whose
+instantiation was suppressed could unnecessarily instantiate the class's
+virtual functions.  This no longer occurs when the specialization has external
+linkage and its virtual function table is suppressed.  A GNU "inline template"
+directive still requires the virtual functions.  For example, with
+--c++11 -tused:
+
+  template<int N> struct C {
+    virtual void f() {
+      static_assert(N != 1, "");  // Previously a spurious error, now okay.
+    }
+  };
+  extern template class C<1>;
+  C<1> c;
diff --git a/tests/tests/regressions/.gh-431-diag.rto/default.1.1.txt b/tests/tests/regressions/.gh-431-diag.rto/default.1.1.txt
new file mode 100644
index 0000000000..d984e4570b
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-diag.rto/default.1.1.txt
@@ -0,0 +1,127 @@
+fe_only -DTEST_NUMBER=1 -tused --c++11 Test_name.c
+"Test_name.c", line 11: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 11: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_call::C<T>::f() [with T=int]" at line 20
+
+"Test_name.c", line 33: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 33: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_call_inline_out_of_class::C<T>::f() [with T=int]" at line 40
+
+"Test_name.c", line 50: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 50: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void explicit_instantiation::C<T>::f() [with T=int]" at line 56
+
+"Test_name.c", line 84: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 84: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_inline_out_of_class::C<T>::f() [with T=int]" at line 88
+
+"Test_name.c", line 223: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 223: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_virtual_call::C<T>::f() [with T=int]" at line 232
+
+"Test_name.c", line 245: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 245: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_virtual_call_inline_out_of_class::C<T>::f() [with T=int]" at line 252
+
+"Test_name.c", line 68: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 68: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_out_of_class::C<T>::f() [with T=int]" at line 72
+
+"Test_name.c", line 97: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 97: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void derived_vtable::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 121: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 121: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void derived_vtable_inline_out_of_class::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 145: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 145: note: the final comparison was 1 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void internal_linkage::C<T>::f() [with T=internal_linkage::<unnamed>::Local]" 
+
+"Test_name.c", line 168: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 168: note: the final comparison was 1 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void internal_linkage_inline_out_of_class::C<T>::f() [with T=internal_linkage_inline_out_of_class::<unnamed>::Local]" 
+
+"Test_name.c", line 183: error: static assertion failed with ""
+          static_assert(sizeof(T) == 0, "");
+          ^
+"Test_name.c", line 183: note: the final comparison was 4 == 0
+          static_assert(sizeof(T) == 0, "");
+                                  ^
+          detected during instantiation of "void internal_linkage_template::<unnamed>::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 207: error: static assertion failed with ""
+        static_assert(P == nullptr, "");
+        ^
+          detected during instantiation of "void internal_linkage_nontype_argument::C<P>::f() [with P=&internal_linkage_nontype_argument::value]" 
+
+"Test_name.c", line 262: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 262: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void specialized_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 287: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 287: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void nontemplate_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 314: error: static assertion failed with ""
+        static_assert(N != 2, "");
+        ^
+"Test_name.c", line 314: note: the final comparison was 2 != 2
+        static_assert(N != 2, "");
+                        ^
+          detected during instantiation of "void unsuppressed_specialization::C<N>::f() [with N=2]" 
+
+16 errors detected in the compilation of "Test_name.c".
diff --git a/tests/tests/regressions/.gh-431-diag.rto/default.2.1.txt b/tests/tests/regressions/.gh-431-diag.rto/default.2.1.txt
new file mode 100644
index 0000000000..e6575e340e
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-diag.rto/default.2.1.txt
@@ -0,0 +1,143 @@
+fe_only -DTEST_NUMBER=2 -tused --gnu_version 150200 Test_name.c
+"Test_name.c", line 11: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 11: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_call::C<T>::f() [with T=int]" at line 20
+
+"Test_name.c", line 33: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 33: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_call_inline_out_of_class::C<T>::f() [with T=int]" at line 40
+
+"Test_name.c", line 50: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 50: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void explicit_instantiation::C<T>::f() [with T=int]" at line 56
+
+"Test_name.c", line 68: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 68: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_out_of_class::C<T>::f() [with T=int]" at line 72
+
+"Test_name.c", line 84: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 84: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_inline_out_of_class::C<T>::f() [with T=int]" at line 88
+
+"Test_name.c", line 97: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 97: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void derived_vtable::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 121: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 121: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void derived_vtable_inline_out_of_class::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 145: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 145: note: the final comparison was 1 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void internal_linkage::C<T>::f() [with T=internal_linkage::<unnamed>::Local]" 
+
+"Test_name.c", line 168: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 168: note: the final comparison was 1 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void internal_linkage_inline_out_of_class::C<T>::f() [with T=internal_linkage_inline_out_of_class::<unnamed>::Local]" 
+
+"Test_name.c", line 183: error: static assertion failed with ""
+          static_assert(sizeof(T) == 0, "");
+          ^
+"Test_name.c", line 183: note: the final comparison was 4 == 0
+          static_assert(sizeof(T) == 0, "");
+                                  ^
+          detected during instantiation of "void internal_linkage_template::<unnamed>::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 207: error: static assertion failed with ""
+        static_assert(P == nullptr, "");
+        ^
+          detected during instantiation of "void internal_linkage_nontype_argument::C<P>::f() [with P=&internal_linkage_nontype_argument::value]" 
+
+"Test_name.c", line 223: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 223: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_virtual_call::C<T>::f() [with T=int]" at line 232
+
+"Test_name.c", line 245: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 245: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_virtual_call_inline_out_of_class::C<T>::f() [with T=int]" at line 252
+
+"Test_name.c", line 262: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 262: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void specialized_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 287: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 287: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void nontemplate_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 314: error: static assertion failed with ""
+        static_assert(N != 2, "");
+        ^
+"Test_name.c", line 314: note: the final comparison was 2 != 2
+        static_assert(N != 2, "");
+                        ^
+          detected during instantiation of "void unsuppressed_specialization::C<N>::f() [with N=2]" 
+
+"Test_name.c", line 331: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 331: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void inline_template::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 349: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 349: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void inline_template_inline_out_of_class::C<T>::f() [with T=int]" 
+
+18 errors detected in the compilation of "Test_name.c".
diff --git a/tests/tests/regressions/.gh-431-diag.rto/default.3.1.txt b/tests/tests/regressions/.gh-431-diag.rto/default.3.1.txt
new file mode 100644
index 0000000000..02707b6168
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-diag.rto/default.3.1.txt
@@ -0,0 +1,127 @@
+fe_only -DTEST_NUMBER=3 -tused --clang_version 220100 Test_name.c
+"Test_name.c", line 11: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 11: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_call::C<T>::f() [with T=int]" at line 20
+
+"Test_name.c", line 33: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 33: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_call_inline_out_of_class::C<T>::f() [with T=int]" at line 40
+
+"Test_name.c", line 50: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 50: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void explicit_instantiation::C<T>::f() [with T=int]" at line 56
+
+"Test_name.c", line 68: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 68: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_out_of_class::C<T>::f() [with T=int]" at line 72
+
+"Test_name.c", line 84: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 84: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_inline_out_of_class::C<T>::f() [with T=int]" at line 88
+
+"Test_name.c", line 97: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 97: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void derived_vtable::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 121: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 121: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void derived_vtable_inline_out_of_class::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 145: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 145: note: the final comparison was 1 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void internal_linkage::C<T>::f() [with T=internal_linkage::<unnamed>::Local]" 
+
+"Test_name.c", line 168: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 168: note: the final comparison was 1 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void internal_linkage_inline_out_of_class::C<T>::f() [with T=internal_linkage_inline_out_of_class::<unnamed>::Local]" 
+
+"Test_name.c", line 183: error: static assertion failed with ""
+          static_assert(sizeof(T) == 0, "");
+          ^
+"Test_name.c", line 183: note: the final comparison was 4 == 0
+          static_assert(sizeof(T) == 0, "");
+                                  ^
+          detected during instantiation of "void internal_linkage_template::<unnamed>::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 207: error: static assertion failed with ""
+        static_assert(P == nullptr, "");
+        ^
+          detected during instantiation of "void internal_linkage_nontype_argument::C<P>::f() [with P=&internal_linkage_nontype_argument::value]" 
+
+"Test_name.c", line 223: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 223: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_virtual_call::C<T>::f() [with T=int]" at line 232
+
+"Test_name.c", line 245: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 245: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_virtual_call_inline_out_of_class::C<T>::f() [with T=int]" at line 252
+
+"Test_name.c", line 262: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 262: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void specialized_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 287: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 287: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void nontemplate_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 314: error: static assertion failed with ""
+        static_assert(N != 2, "");
+        ^
+"Test_name.c", line 314: note: the final comparison was 2 != 2
+        static_assert(N != 2, "");
+                        ^
+          detected during instantiation of "void unsuppressed_specialization::C<N>::f() [with N=2]" 
+
+16 errors detected in the compilation of "Test_name.c".
diff --git a/tests/tests/regressions/.gh-431-diag.rto/default.4.1.txt b/tests/tests/regressions/.gh-431-diag.rto/default.4.1.txt
new file mode 100644
index 0000000000..f346ee5710
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-diag.rto/default.4.1.txt
@@ -0,0 +1,103 @@
+fe_only -DTEST_NUMBER=4 -tused --ms_c++20 --microsoft_version 1950 Test_name.c
+"Test_name.c", line 11: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 11: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_call::C<T>::f() [with T=int]" at line 20
+
+"Test_name.c", line 33: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 33: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_call_inline_out_of_class::C<T>::f() [with T=int]" at line 40
+
+"Test_name.c", line 50: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 50: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void explicit_instantiation::C<T>::f() [with T=int]" at line 56
+
+"Test_name.c", line 68: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 68: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_out_of_class::C<T>::f() [with T=int]" at line 72
+
+"Test_name.c", line 84: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 84: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void explicit_instantiation_inline_out_of_class::C<T>::f() [with T=int]" at line 88
+
+"Test_name.c", line 97: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 97: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void derived_vtable::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 121: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 121: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void derived_vtable_inline_out_of_class::C<T>::f() [with T=int]" 
+
+"Test_name.c", line 207: error: static assertion failed with ""
+        static_assert(P == nullptr, "");
+        ^
+          detected during instantiation of "void internal_linkage_nontype_argument::C<P>::f() [with P=&internal_linkage_nontype_argument::value]" 
+
+"Test_name.c", line 223: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 223: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void direct_virtual_call::C<T>::f() [with T=int]" at line 232
+
+"Test_name.c", line 245: error: static assertion failed with ""
+      static_assert(sizeof(T) == 0, "");
+      ^
+"Test_name.c", line 245: note: the final comparison was 4 == 0
+      static_assert(sizeof(T) == 0, "");
+                              ^
+          detected during instantiation of "void direct_virtual_call_inline_out_of_class::C<T>::f() [with T=int]" at line 252
+
+"Test_name.c", line 262: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 262: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void specialized_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 287: error: static assertion failed with ""
+        static_assert(sizeof(T) == 0, "");
+        ^
+"Test_name.c", line 287: note: the final comparison was 4 == 0
+        static_assert(sizeof(T) == 0, "");
+                                ^
+          detected during instantiation of "void nontemplate_nested_class::Base<T>::f() [with T=int]" 
+
+"Test_name.c", line 314: error: static assertion failed with ""
+        static_assert(N != 2, "");
+        ^
+"Test_name.c", line 314: note: the final comparison was 2 != 2
+        static_assert(N != 2, "");
+                        ^
+          detected during instantiation of "void unsuppressed_specialization::C<N>::f() [with N=2]" 
+
+13 errors detected in the compilation of "Test_name.c".
diff --git a/tests/tests/regressions/.gh-431-ia64.rto/default.1.1.txt b/tests/tests/regressions/.gh-431-ia64.rto/default.1.1.txt
new file mode 100644
index 0000000000..fcf5b546e4
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-ia64.rto/default.1.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=1 -tused --c++11 Test_name.c
diff --git a/tests/tests/regressions/.gh-431-ia64.rto/default.2.1.txt b/tests/tests/regressions/.gh-431-ia64.rto/default.2.1.txt
new file mode 100644
index 0000000000..7a2ce534cb
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-ia64.rto/default.2.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=2 -tused --gnu_version 150200 Test_name.c
diff --git a/tests/tests/regressions/.gh-431-ia64.rto/default.3.1.txt b/tests/tests/regressions/.gh-431-ia64.rto/default.3.1.txt
new file mode 100644
index 0000000000..6d6dc6d606
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-ia64.rto/default.3.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=3 -tused --clang_version 220100 Test_name.c
diff --git a/tests/tests/regressions/.gh-431-ia64.rto/default.4.1.txt b/tests/tests/regressions/.gh-431-ia64.rto/default.4.1.txt
new file mode 100644
index 0000000000..6c55ae241d
--- /dev/null
+++ b/tests/tests/regressions/.gh-431-ia64.rto/default.4.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=4 -tused --ms_c++20 --microsoft_version 1950 Test_name.c
diff --git a/tests/tests/regressions/.gh-431.rto/default.1.1.txt b/tests/tests/regressions/.gh-431.rto/default.1.1.txt
new file mode 100644
index 0000000000..fcf5b546e4
--- /dev/null
+++ b/tests/tests/regressions/.gh-431.rto/default.1.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=1 -tused --c++11 Test_name.c
diff --git a/tests/tests/regressions/.gh-431.rto/default.2.1.txt b/tests/tests/regressions/.gh-431.rto/default.2.1.txt
new file mode 100644
index 0000000000..7a2ce534cb
--- /dev/null
+++ b/tests/tests/regressions/.gh-431.rto/default.2.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=2 -tused --gnu_version 150200 Test_name.c
diff --git a/tests/tests/regressions/.gh-431.rto/default.3.1.txt b/tests/tests/regressions/.gh-431.rto/default.3.1.txt
new file mode 100644
index 0000000000..6d6dc6d606
--- /dev/null
+++ b/tests/tests/regressions/.gh-431.rto/default.3.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=3 -tused --clang_version 220100 Test_name.c
diff --git a/tests/tests/regressions/.gh-431.rto/default.4.1.txt b/tests/tests/regressions/.gh-431.rto/default.4.1.txt
new file mode 100644
index 0000000000..6c55ae241d
--- /dev/null
+++ b/tests/tests/regressions/.gh-431.rto/default.4.1.txt
@@ -0,0 +1 @@
+fe_only -DTEST_NUMBER=4 -tused --ms_c++20 --microsoft_version 1950 Test_name.c
diff --git a/tests/tests/regressions/gh-431-diag.sft.cpp b/tests/tests/regressions/gh-431-diag.sft.cpp
new file mode 100644
index 0000000000..72784bedee
--- /dev/null
+++ b/tests/tests/regressions/gh-431-diag.sft.cpp
@@ -0,0 +1,355 @@
+//type:fn
+//options_all:-tused
+//options:--c++11:--gnu_version 150200:--clang_version 220100:--ms_c++20 --microsoft_version 1950
+
+namespace direct_call
+{
+  template<class T> struct C
+  {
+    void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int>;
+
+  /* An extern template declaration must not suppress inline body checking. */
+  void g(C<int>& c)
+  {
+    c.f();
+  }
+}
+
+namespace direct_call_inline_out_of_class
+{
+  template<class T> struct C
+  {
+    void f();
+  };
+
+  template<class T> inline void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<int>;
+
+  void g(C<int>& c)
+  {
+    c.f();
+  }
+}
+
+namespace explicit_instantiation
+{
+  template<class T> struct C
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int>;
+  /* A subsequent explicit instantiation must instantiate the virtual member. */
+  template struct C<int>;
+}
+
+namespace explicit_instantiation_out_of_class
+{
+  template<class T> struct C
+  {
+    virtual void f();
+  };
+
+  template<class T> void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<int>;
+  template struct C<int>;
+}
+
+namespace explicit_instantiation_inline_out_of_class
+{
+  template<class T> struct C
+  {
+    virtual void f();
+  };
+
+  template<class T> inline void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<int>;
+  template struct C<int>;
+}
+
+namespace derived_vtable
+{
+  template<class T> struct C
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int>;
+  struct D : C<int>
+  {};
+
+  /* The derived vtable still needs the inherited virtual member. */
+  D *g()
+  {
+    return new D();
+  }
+}
+
+namespace derived_vtable_inline_out_of_class
+{
+  template<class T> struct C
+  {
+    virtual void f();
+  };
+
+  template<class T> inline void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<int>;
+  struct D : C<int>
+  {};
+
+  D *g()
+  {
+    return new D();
+  }
+}
+
+namespace internal_linkage
+{
+  namespace
+  {
+    struct Local {};
+  }
+
+  template<class T> struct C
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<Local>;
+  /* A specialization with internal linkage still gets a local vtable. */
+  C<Local> c;
+}
+
+namespace internal_linkage_inline_out_of_class
+{
+  namespace
+  {
+    struct Local {};
+  }
+
+  template<class T> struct C
+  {
+    virtual void f();
+  };
+
+  template<class T> inline void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<Local>;
+  C<Local> c;
+}
+
+namespace internal_linkage_template
+{
+  namespace
+  {
+    template<class T> struct C
+    {
+      virtual void f()
+      {
+        static_assert(sizeof(T) == 0, "");
+      }
+    };
+
+    extern template struct C<int>;
+
+    /* The template itself has internal linkage, even with an external arg. */
+    C<int> c;
+  }
+
+  void *g()
+  {
+    return &c;
+  }
+}
+
+namespace internal_linkage_nontype_argument
+{
+  static int value;
+
+  template<int *P> struct C
+  {
+    virtual void f()
+    {
+      static_assert(P == nullptr, "");
+    }
+  };
+
+  extern template struct C<&value>;
+
+  /* A pointer to an internal-linkage object makes the instance local too. */
+  C<&value> c;
+}
+
+namespace direct_virtual_call
+{
+  template<class T> struct C
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int>;
+
+  /* Suppressing the vtable must not suppress a qualified inline call. */
+  void g(C<int>& c)
+  {
+    c.C<int>::f();
+  }
+}
+
+namespace direct_virtual_call_inline_out_of_class
+{
+  template<class T> struct C
+  {
+    virtual void f();
+  };
+
+  template<class T> inline void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<int>;
+
+  void g(C<int>& c)
+  {
+    c.C<int>::f();
+  }
+}
+
+namespace specialized_nested_class
+{
+  template<class T> struct Base
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct Base<int>;
+
+  template<class T> struct C
+  {
+    struct D;
+  };
+
+  template<> struct C<int>::D : Base<int> {};
+
+  /* Propagation of suppression must not suppress a specialized class's
+     vtable or its inherited virtual functions. */
+  extern template struct C<int>;
+  C<int>::D d;
+}
+
+namespace nontemplate_nested_class
+{
+  template<class T> struct Base
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct Base<int>;
+
+  template<class T> struct C
+  {
+    struct D;
+  };
+
+  template<> struct C<int>::D
+  {
+    struct E : Base<int> {};
+  };
+
+  /* Suppression also propagates to E, which is not a template instance. */
+  extern template struct C<int>;
+  C<int>::D::E e;
+}
+
+namespace unsuppressed_specialization
+{
+  template<int N> struct C
+  {
+    virtual void f()
+    {
+      static_assert(N != 2, "");
+    }
+  };
+
+  extern template struct C<1>;
+
+  /* Suppression applies only to the named specialization. */
+  C<2> c;
+}
+
+#if defined(__GNUC__) && !defined(__clang__)
+namespace inline_template
+{
+  template<class T> struct C
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int>;
+  /* GNU inline template explicitly requests a local vtable. */
+  inline template struct C<int>;
+}
+
+namespace inline_template_inline_out_of_class
+{
+  template<class T> struct C
+  {
+    virtual void f();
+  };
+
+  template<class T> inline void C<T>::f()
+  {
+    static_assert(sizeof(T) == 0, "");
+  }
+
+  extern template struct C<int>;
+  inline template struct C<int>;
+}
+#endif
diff --git a/tests/tests/regressions/gh-431-ia64.sft.cpp b/tests/tests/regressions/gh-431-ia64.sft.cpp
new file mode 100644
index 0000000000..fafeccaebd
--- /dev/null
+++ b/tests/tests/regressions/gh-431-ia64.sft.cpp
@@ -0,0 +1,105 @@
+//type:fp
+//options:--c++11:--gnu_version 150200:--clang_version 220100:--ms_c++20 --microsoft_version 1950
+//options_all:-tused
+//requires:IA64_ABI=1
+
+namespace in_class
+{
+  template<int N>
+  struct C
+  {
+    virtual void f()
+    {
+      static_assert(N != 1, "");
+    }
+  };
+
+  extern template class C<1>;
+
+  C<1> c;
+}
+
+namespace external_linkage
+{
+  struct External {};
+
+  template<class T> struct C
+  {
+    C() {}
+    ~C() {}
+
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<External>;
+
+  /* Both user-defined bodies are checked, but the vtable is suppressed. */
+  void g()
+  {
+    C<External> c;
+  }
+}
+
+namespace partial_specialization
+{
+  template<class T> struct C;
+
+  template<class T> struct C<T*>
+  {
+    C() {}
+    virtual ~C() {}
+
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int*>;
+
+  /* A partial specialization is still subject to extern template. */
+  void g()
+  {
+    C<int*> c;
+  }
+}
+
+#if defined(__GNUC__) || defined(__clang__)
+namespace hidden_external_linkage
+{
+  template<class T> struct __attribute__((visibility("hidden"))) C
+  {
+    virtual void f()
+    {
+      static_assert(sizeof(T) == 0, "");
+    }
+  };
+
+  extern template struct C<int>;
+
+  /* Hidden visibility is not internal linkage: suppress this vtable too. */
+  C<int> c;
+}
+#endif
+
+namespace inline_out_of_class
+{
+  template<int N>
+  struct C
+  {
+    virtual void f();
+  };
+
+  template<int N>
+  inline void C<N>::f()
+  {
+    static_assert(N != 1, "");
+  }
+
+  extern template class C<1>;
+
+  C<1> c;
+}
diff --git a/tests/tests/regressions/gh-431-link/.t1.rto/default.1.1.txt b/tests/tests/regressions/gh-431-link/.t1.rto/default.1.1.txt
new file mode 100644
index 0000000000..64d6aa5453
--- /dev/null
+++ b/tests/tests/regressions/gh-431-link/.t1.rto/default.1.1.txt
@@ -0,0 +1,3 @@
+eccp -DTEST_NUMBER=1 --c++11 -tused t2.cpp Test_name.c
+t2.cpp:
+Test_name.c:
diff --git a/tests/tests/regressions/gh-431-link/.t1.rto/default.1.2.txt b/tests/tests/regressions/gh-431-link/.t1.rto/default.1.2.txt
new file mode 100644
index 0000000000..ff2642c6d5
--- /dev/null
+++ b/tests/tests/regressions/gh-431-link/.t1.rto/default.1.2.txt
@@ -0,0 +1 @@
+./a.out
diff --git a/tests/tests/regressions/gh-431-link/t1.mft.cpp b/tests/tests/regressions/gh-431-link/t1.mft.cpp
new file mode 100644
index 0000000000..28cdb3ce45
--- /dev/null
+++ b/tests/tests/regressions/gh-431-link/t1.mft.cpp
@@ -0,0 +1,18 @@
+//type:rp
+//options:--c++11 -tused t2.cpp
+//source_files:t2.cpp
+
+template<int N>
+struct C {
+  virtual int f() { return N; }
+};
+
+extern template struct C<1>;
+
+C<1> c;
+C<1> *p = &c;
+
+int main()
+{
+  return p->f() != 1;
+}
diff --git a/tests/tests/regressions/gh-431-link/t2.cpp b/tests/tests/regressions/gh-431-link/t2.cpp
new file mode 100644
index 0000000000..27d556805f
--- /dev/null
+++ b/tests/tests/regressions/gh-431-link/t2.cpp
@@ -0,0 +1,6 @@
+template<int N>
+struct C {
+  virtual int f() { return N; }
+};
+
+template struct C<1>;
diff --git a/tests/tests/regressions/gh-431.sft.cpp b/tests/tests/regressions/gh-431.sft.cpp
new file mode 100644
index 0000000000..7e29b3c582
--- /dev/null
+++ b/tests/tests/regressions/gh-431.sft.cpp
@@ -0,0 +1,44 @@
+//type:fp
+//options:--c++11:--gnu_version 150200:--clang_version 220100:--ms_c++20 --microsoft_version 1950
+//options_all:-tused
+
+namespace out_of_class
+{
+  template<int N>
+  struct C
+  {
+    virtual void f();
+  };
+
+  template<int N>
+  void C<N>::f()
+  {
+    static_assert(N != 1, "");
+  }
+
+  extern template class C<1>;
+
+  C<1> c;
+}
+
+namespace constant_evaluation
+{
+  template<class T>
+  struct C
+  {
+    static constexpr int f()
+    {
+      return 42;
+    }
+
+    constexpr int g() const
+    {
+      return 43;
+    }
+  };
+
+  extern template struct C<int>;
+
+  static_assert(C<int>::f() == 42, "");
+  static_assert(C<int>{}.g() == 43, "");
+}