From: Marek Polacek <polacek@redhat.com>
Date: Tue, 18 Nov 2025 20:23:20 +0000 (-0500)
Subject: c++: fix ICE when comparing targs [PR119580]
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e2faea35a1edf6fca4d98800a1d9566db04a133b;p=thirdparty%2Fgcc.git

c++: fix ICE when comparing targs [PR119580]

In r10-7816, cp_tree_equal/TEMPLATE_ID_EXPR was changed to use
comp_template_args to compare the targs.  This makes sense, but
comp_template_args won't deal with an error_mark_node.  We created
a BASELINK for S::foo<T::value_type>, but since value_type couldn't
be looked up, we ended up with an error_mark_node instead of a TREE_VEC
of arguments for the TEMPLATE_ID_EXPR in the BASELINK.

It seems reasonable not to create such a TEMPLATE_ID_EXPR by checking
the result of tsubst_template_args like we do in so many other places.
This changes the diagnostic in three tests, but it's only the followup
error message after complaining about the type/value mismatch.

	PR c++/119580

gcc/cp/ChangeLog:

	* pt.cc (tsubst_baselink): Return error_mark_node if
	tsubst_template_args returned error_mark_node.

gcc/testsuite/ChangeLog:

	* g++.dg/template/crash106.C: Adjust expected diagnostics.
	* g++.dg/template/crash112.C: Likewise.
	* g++.dg/template/dependent-args1.C: Likewise.
	* g++.dg/cpp0x/pr119580.C: New test.

Reviewed-by: Jason Merrill <jason@redhat.com>
---

diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 6dc3a4c3249..0daf43c681b 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -17595,6 +17595,8 @@ tsubst_baselink (tree baselink, tree object_type,
       if (template_args)
 	template_args = tsubst_template_args (template_args, args,
 					      complain, in_decl);
+      if (template_args == error_mark_node)
+	return error_mark_node;
     }
 
   tree binfo_type = BINFO_TYPE (BASELINK_BINFO (baselink));
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr119580.C b/gcc/testsuite/g++.dg/cpp0x/pr119580.C
new file mode 100644
index 00000000000..598ddbb0e61
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/pr119580.C
@@ -0,0 +1,16 @@
+// PR c++/119580
+// { dg-do compile { target c++11 } }
+
+template<typename> struct V;
+template<typename> class C;
+class F;
+
+struct S {
+  template<typename>
+  static void foo ();
+  template<typename T, typename>
+  C<decltype(S::foo<T::value_type>)> foo ();
+  decltype(foo<V<F>>()) *a;
+};
+
+S s;
diff --git a/gcc/testsuite/g++.dg/template/crash106.C b/gcc/testsuite/g++.dg/template/crash106.C
index 35cedb55b0b..bb71e29b1a6 100644
--- a/gcc/testsuite/g++.dg/template/crash106.C
+++ b/gcc/testsuite/g++.dg/template/crash106.C
@@ -7,6 +7,6 @@ struct A
   template<T> void foo(); // { dg-error "type" "" { target c++17_down } }
 };
 
-template<T N = 0.0, void (A::*)() = &A::foo<N> > struct B {}; // { dg-error "type|declared|could not convert" "" { target c++17_down } }
+template<T N = 0.0, void (A::*)() = &A::foo<N> > struct B {}; // { dg-error "type|not a member" "" { target c++17_down } }
 
-B<> b; // { dg-message "" "" { target c++17_down } }
+B<> b; // { dg-error "invalid" "" { target c++17_down } }
diff --git a/gcc/testsuite/g++.dg/template/crash112.C b/gcc/testsuite/g++.dg/template/crash112.C
index ff35764c7c7..a60b2332562 100644
--- a/gcc/testsuite/g++.dg/template/crash112.C
+++ b/gcc/testsuite/g++.dg/template/crash112.C
@@ -9,9 +9,7 @@ template<void (A::*)()> struct B {};
 
 template<int> struct C
 {
-  B<&A::foo<int int> > b; // { dg-error "declaration|type" }
+  B<&A::foo<int int> > b; // { dg-error "declaration|not a member" }
 };
 
 C<0> c;
-
-// { dg-prune-output "could not convert" }
diff --git a/gcc/testsuite/g++.dg/template/dependent-args1.C b/gcc/testsuite/g++.dg/template/dependent-args1.C
index 8fffbf85317..1f16206c706 100644
--- a/gcc/testsuite/g++.dg/template/dependent-args1.C
+++ b/gcc/testsuite/g++.dg/template/dependent-args1.C
@@ -6,8 +6,6 @@ struct A
   template<int> void foo();
 };
 
-template<int N, void (A::*)() = &A::foo<N> > struct B {};
+template<int N, void (A::*)() = &A::foo<N> > struct B {};  // { dg-error "not a member" }
 
-B<int> b; // { dg-error "type/value mismatch|expected a constant|invalid type" }
-
-// { dg-prune-output "(could not convert|no match)" }
+B<int> b; // { dg-error "type/value mismatch|invalid" }