From: Jason Merrill <jason@redhat.com>
Date: Mon, 12 Aug 2019 17:46:32 +0000 (-0400)
Subject: PR c++/91378 - ICE with noexcept and auto return type.
X-Git-Tag: releases/gcc-9.3.0~744
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0b8c26032610d97d92a4d14a9ebb693fec0f75b8;p=thirdparty%2Fgcc.git

PR c++/91378 - ICE with noexcept and auto return type.

Here, since the call to g is not type-dependent, we call mark_used on it to
determine its return type.  This also wants to instantiate the
noexcept-expression.  But since nothing in maybe_instantiate_noexcept was
calling push_to_top_level, we substituted b.i with processing_template_decl
set, so we left it unresolved for later access checking.  As a result, the
type of C::g<int> remained instantiation-dependent, leading to an ICE in
type_dependent_expression_p on the assert that the type of a function
template with no dependent template arguments must be non-dependent.

	* pt.c (maybe_instantiate_noexcept): push_to_top_level.

From-SVN: r274316
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 9a34a4f128e2..67ce26866bb9 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,8 @@
 2019-08-12  Jason Merrill  <jason@redhat.com>
 
+	PR c++/91378 - ICE with noexcept and auto return type.
+	* pt.c (maybe_instantiate_noexcept): push_to_top_level.
+
 	PR c++/90538 - multiple expansions of capture packs
 	* cp-tree.h (DECLTYPE_FOR_INIT_CAPTURE): Remove.
 	* lambda.c (add_capture): Copy parameter packs from init.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index dd2dd2940bfe..b3fe901097c8 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -24323,12 +24323,11 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 	}
       else if (push_tinst_level (fn))
 	{
+	  push_to_top_level ();
 	  push_access_scope (fn);
 	  push_deferring_access_checks (dk_no_deferred);
 	  input_location = DECL_SOURCE_LOCATION (fn);
 
-	  tree save_ccp = current_class_ptr;
-	  tree save_ccr = current_class_ref;
 	  /* If needed, set current_class_ptr for the benefit of
 	     tsubst_copy/PARM_DECL.  */
 	  tree tdecl = DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (fn));
@@ -24354,9 +24353,6 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 					/*function_p=*/false,
 					/*i_c_e_p=*/true);
 
-	  current_class_ptr = save_ccp;
-	  current_class_ref = save_ccr;
-
 	  /* Build up the noexcept-specification.  */
 	  spec = build_noexcept_spec (noex, tf_warning_or_error);
 
@@ -24366,6 +24362,7 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
 	  pop_deferring_access_checks ();
 	  pop_access_scope (fn);
 	  pop_tinst_level ();
+	  pop_from_top_level ();
 	}
       else
 	spec = noexcept_false_spec;
diff --git a/gcc/testsuite/g++.dg/cpp1y/auto-fn56.C b/gcc/testsuite/g++.dg/cpp1y/auto-fn56.C
new file mode 100644
index 000000000000..69bdd9586eb9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/auto-fn56.C
@@ -0,0 +1,19 @@
+// PR c++/91378
+// { dg-do compile { target c++14 } }
+
+struct B
+{
+  int i;
+};
+
+struct C
+{
+  template <class T> static auto
+  g(B b) noexcept(noexcept(b.i)) { }
+};
+
+template <class T>
+void h(T t)
+{
+  C::g<int>({});
+}