On 10/24/22 13:13, Marek Polacek wrote:
On Mon, Oct 24, 2022 at 10:31:50AM -0400, Jason Merrill wrote:
On 10/21/22 19:29, Marek Polacek wrote:
This test ICEs in C++23 because we reach the new code in do_auto_deduction:
30468 if (cxx_dialect >= cxx23
30469 && context == adc_return_type
30470 && (!AUTO_IS_DECLTYPE (auto_node)
30471 || !unparenthesized_id_or_class_member_access_p (init))
30472 && (r = treat_lvalue_as_rvalue_p (maybe_undo_parenthesized_ref
(init),
30473 /*return*/true)))
where 'init' is "VIEW_CONVERT_EXPR<<<< error >>>>(y)", and then the move
in treat_lvalue_as_rvalue_p returns error_mark_node whereupon
set_implicit_rvalue_p crashes.
I don't think such V_C_Es are useful so let's not create them. But that
won't fix the ICE so I'm checking the return value of move. A structured
bindings decl can have an error type, that is set in cp_finish_decomp:
8908 TREE_TYPE (first) = error_mark_node;
therefore I think treat_lvalue_as_rvalue_p just needs to cope.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
PR c++/107276
gcc/cp/ChangeLog:
* typeck.cc (treat_lvalue_as_rvalue_p): Check the return value of move.
gcc/ChangeLog:
* tree.cc (maybe_wrap_with_location): Don't create a location wrapper
when the type is erroneous.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/decomp4.C: New test.
---
gcc/cp/typeck.cc | 7 ++++++-
gcc/testsuite/g++.dg/cpp2a/decomp4.C | 8 ++++++++
gcc/tree.cc | 3 ++-
3 files changed, 16 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/decomp4.C
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 16e7d85793d..5ca191759f6 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -10726,7 +10726,12 @@ treat_lvalue_as_rvalue_p (tree expr, bool return_p)
if (DECL_CONTEXT (retval) != current_function_decl)
return NULL_TREE;
if (return_p)
- return set_implicit_rvalue_p (move (expr));
+ {
+ expr = move (expr);
+ if (expr == error_mark_node)
+ return NULL_TREE;
+ return set_implicit_rvalue_p (expr);
+ }
/* if the operand of a throw-expression is a (possibly parenthesized)
id-expression that names an implicitly movable entity whose scope does
not
diff --git a/gcc/testsuite/g++.dg/cpp2a/decomp4.C
b/gcc/testsuite/g++.dg/cpp2a/decomp4.C
new file mode 100644
index 00000000000..28b3f172b53
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/decomp4.C
@@ -0,0 +1,8 @@
+// PR c++/107276
+// { dg-do run { target c++20 } }
+
+auto f(auto x) {
+ auto [y] = x; // { dg-error "cannot decompose" }
+ return y;
+}
+int i = f(0);
diff --git a/gcc/tree.cc b/gcc/tree.cc
index 81a6ceaf181..4e5b1df4d85 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -14352,7 +14352,8 @@ maybe_wrap_with_location (tree expr, location_t loc)
/* For now, don't add wrappers to exceptional tree nodes, to minimize
any impact of the wrapper nodes. */
- if (EXCEPTIONAL_CLASS_P (expr))
+ if (EXCEPTIONAL_CLASS_P (expr)
+ || (TREE_TYPE (expr) && EXCEPTIONAL_CLASS_P (TREE_TYPE (expr))))
I think check error_operand_p instead; I don't think it makes sense to look
for other exceptional nodes in TREE_TYPE.
Makes sense. I don't suppose you want to replace the whole condition with
error_operand_p, only what comes after ||. Updated patch below, thanks.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
-- >8 --
This test ICEs in C++23 because we reach the new code in do_auto_deduction:
30468 if (cxx_dialect >= cxx23
30469 && context == adc_return_type
30470 && (!AUTO_IS_DECLTYPE (auto_node)
30471 || !unparenthesized_id_or_class_member_access_p (init))
30472 && (r = treat_lvalue_as_rvalue_p (maybe_undo_parenthesized_ref
(init),
30473 /*return*/true)))
where 'init' is "VIEW_CONVERT_EXPR<<<< error >>>>(y)", and then the move
in treat_lvalue_as_rvalue_p returns error_mark_node whereupon
set_implicit_rvalue_p crashes.
I don't think such V_C_Es are useful so let's not create them. But that
won't fix the ICE so I'm checking the return value of move. A structured
bindings decl can have an error type, that is set in cp_finish_decomp:
8908 TREE_TYPE (first) = error_mark_node;
therefore I think treat_lvalue_as_rvalue_p just needs to cope.
PR c++/107276
gcc/cp/ChangeLog:
* typeck.cc (treat_lvalue_as_rvalue_p): Check the return value of move.
gcc/ChangeLog:
* tree.cc (maybe_wrap_with_location): Don't create a location wrapper
when the type is erroneous.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/decomp4.C: New test.
---
gcc/cp/typeck.cc | 7 ++++++-
gcc/testsuite/g++.dg/cpp2a/decomp4.C | 8 ++++++++
gcc/tree.cc | 2 +-
3 files changed, 15 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/decomp4.C
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 16e7d85793d..5ca191759f6 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -10726,7 +10726,12 @@ treat_lvalue_as_rvalue_p (tree expr, bool return_p)
if (DECL_CONTEXT (retval) != current_function_decl)
return NULL_TREE;
if (return_p)
- return set_implicit_rvalue_p (move (expr));
+ {
+ expr = move (expr);
+ if (expr == error_mark_node)
+ return NULL_TREE;
+ return set_implicit_rvalue_p (expr);
+ }
/* if the operand of a throw-expression is a (possibly parenthesized)
id-expression that names an implicitly movable entity whose scope does
not
diff --git a/gcc/testsuite/g++.dg/cpp2a/decomp4.C
b/gcc/testsuite/g++.dg/cpp2a/decomp4.C
new file mode 100644
index 00000000000..d1b0c90ee26
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/decomp4.C
@@ -0,0 +1,8 @@
+// PR c++/107276
+// { dg-do compile { target c++20 } }
+
+auto f(auto x) {
+ auto [y] = x; // { dg-error "cannot decompose" }
+ return y;
+}
+int i = f(0);
diff --git a/gcc/tree.cc b/gcc/tree.cc
index 81a6ceaf181..04603c8c902 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -14352,7 +14352,7 @@ maybe_wrap_with_location (tree expr, location_t loc)
/* For now, don't add wrappers to exceptional tree nodes, to minimize
any impact of the wrapper nodes. */
- if (EXCEPTIONAL_CLASS_P (expr))
+ if (EXCEPTIONAL_CLASS_P (expr) || error_operand_p (expr))
return expr;
/* Compiler-generated temporary variables don't need a wrapper. */
base-commit: 131d18e928a3ea1ab2d3bf61aa92d68a8a254609
