c++: Fix ICE-on-invalid with lambda template [PR94507]

While reducing something else I noticed that we ICE on the following
invalid code.  In tsubst_lambda_expr, tsubst_template_decl has already
reported an error and returned the error_mark_node, so make sure we
don't ICE on that.  I'm using a goto here because we still have to
do finish_struct because it does popclass ().

	PR c++/94507 - ICE-on-invalid with lambda template.
	* pt.c (tsubst_lambda_expr): Cope when tsubst_template_decl or
	tsubst_function_decl returns error_mark_node.

	* g++.dg/cpp2a/lambda-generic7.C: New test.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 7c5edc2..50f1857 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-04-08  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/94507 - ICE-on-invalid with lambda template.
+       * pt.c (tsubst_lambda_expr): Cope when tsubst_template_decl or
+       tsubst_function_decl returns error_mark_node.
+
 2020-04-08  Martin Liska  <mliska@suse.cz>
 
        PR c++/94314

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 256a937..050a57b 100644 (file)
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18953,6 +18953,11 @@ tsubst_lambda_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
       if (oldtmpl)
        {
          tmpl = tsubst_template_decl (oldtmpl, args, complain, fntype);
+         if (tmpl == error_mark_node)
+           {
+             r = error_mark_node;
+             goto out;
+           }
          fn = DECL_TEMPLATE_RESULT (tmpl);
          finish_member_declaration (tmpl);
        }
@@ -18960,6 +18965,11 @@ tsubst_lambda_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
        {
          tmpl = NULL_TREE;
          fn = tsubst_function_decl (oldfn, args, complain, fntype);
+         if (fn == error_mark_node)
+           {
+             r = error_mark_node;
+             goto out;
+           }
          finish_member_declaration (fn);
        }
 
@@ -19025,6 +19035,7 @@ tsubst_lambda_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
       maybe_add_lambda_conv_op (type);
     }
 
+out:
   finish_struct (type, /*attr*/NULL_TREE);
 
   insert_pending_capture_proxies ();

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index db4f639..6ed5114 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-08  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/94507 - ICE-on-invalid with lambda template.
+       * g++.dg/cpp2a/lambda-generic7.C: New test.
+
 2020-04-08  Alexandre Oliva <oliva@adacore.com>
 
        * gcc.target/arm/fp16-aapcs-3.c: Explicitly use the

diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-generic7.C b/gcc/testsuite/g++.dg/cpp2a/lambda-generic7.C
new file mode 100644 (file)
index 0000000..bedba68
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/lambda-generic7.C
@@ -0,0 +1,10 @@
+// PR c++/94507 - ICE-on-invalid with lambda template.
+// { dg-do compile { target c++2a } }
+
+struct S { };
+
+template<typename T, typename U>
+auto foo(T, U)
+{
+  [] <> () { foo (S{}, S{}); }; // { dg-error "expected" }
+}