[PATCH] c++: Fix tsubst ICE with invalid code [PR97993, PR97187]

[Marek Polacek via Gcc-patches]

I had a strong sense of deja vu when looking into this, and no wonder,
since this is almost identical to c++/95728.

Since r11-423 tsubst_copy_and_build/TREE_LIST uses tsubst_tree_list
instead of open coding it.  While the latter could return an error
node wrapped in a TREE_LIST, the former can return a naked error node.

That broke in tsubst_copy_and_build/NEW_EXPR, because we were accessing
TREE_VALUE of an error node.

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

gcc/cp/ChangeLog:

        PR c++/97187
        PR c++/97993
        * pt.c (tsubst_copy_and_build) <case NEW_EXPR>: Return error_mark_node
        if init is erroneous.

gcc/testsuite/ChangeLog:

        PR c++/97187
        PR c++/97993
        * g++.dg/eh/crash2.C: New test.
        * g++.dg/template/crash132.C: New test.
---
 gcc/cp/pt.c                              |  2 ++
 gcc/testsuite/g++.dg/eh/crash2.C         | 20 ++++++++++++++++++++
 gcc/testsuite/g++.dg/template/crash132.C |  6 ++++++
 3 files changed, 28 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/eh/crash2.C
 create mode 100644 gcc/testsuite/g++.dg/template/crash132.C

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 4fb0bc82c31..72d6cc3ad98 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -19829,6 +19829,8 @@ tsubst_copy_and_build (tree t,
           parameter packs are of length zero.  */
        if (init == NULL_TREE && TREE_OPERAND (t, 3) == NULL_TREE)
          init_vec = NULL;
+       else if (init == error_mark_node)
+         RETURN (error_mark_node);
        else
          {
            init_vec = make_tree_vector ();
diff --git a/gcc/testsuite/g++.dg/eh/crash2.C b/gcc/testsuite/g++.dg/eh/crash2.C
new file mode 100644
index 00000000000..fff8e142fd6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/eh/crash2.C
@@ -0,0 +1,20 @@
+// PR c++/97187
+// { dg-do compile { target c++14 } }
+// { dg-options "-fno-exceptions" }
+
+auto yp = [] { return 0; };
+
+template <class DI>
+DI
+zl ()
+{
+  auto au = [] () -> DI { return *new auto (true ? yp : throw); }; // { 
dg-error "exception handling disabled" }
+
+  return au ();
+}
+
+auto
+vd ()
+{
+  return zl <decltype (yp)> ();
+}
diff --git a/gcc/testsuite/g++.dg/template/crash132.C 
b/gcc/testsuite/g++.dg/template/crash132.C
new file mode 100644
index 00000000000..f6f4863e937
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/crash132.C
@@ -0,0 +1,6 @@
+// PR c++/97993
+// { dg-do compile { target c++14 } }
+
+template <class T> T a;
+template <class T, class A, class=decltype(::new T (A()))> auto foo ();
+struct S decltype (foo <int, S>); // { dg-error "" }

base-commit: b46314c78061a5156bac44a317c87d32b00d4295
-- 
2.28.0