Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk/backports?
-- >8 --
r8-7538 for PR84968 made strip_typedefs_expr diagnose seeing
STATEMENT_LIST, which effectively makes us reject statement-expressions
noexcept-specifiers (we already diagnose them in template arguments
at parse time).
Later r11-7452 made decltype(auto) deduction do strip_typedefs_expr on
the expression before deducing (as an implementation detail) and so ever
since we inadvertently reject decltype(auto) deduction of a
statement-expression.
This patch just removes the diagnostic in strip_typedefs_expr; it doesn't
seem like the right place for it. And it lets us accept more code using
statement-expressions in various contexts.
PR c++/116418
PR c++/84968
gcc/cp/ChangeLog:
* tree.cc (strip_typedefs_expr) <case STATEMENT_LIST>: Replace
with ...
<case STMT_EXPR>: ... this non-diagnosing early exit.
gcc/testsuite/ChangeLog:
* g++.dg/eh/pr84968.C: No longer expect ah ahead of time diagnostic
for the statement-expresssion. Instantiate the template and expect
an incomplete type error instead.
* g++.dg/ext/stmtexpr26.C: New test.
---
gcc/cp/tree.cc | 5 ++---
gcc/testsuite/g++.dg/eh/pr84968.C | 4 +++-
gcc/testsuite/g++.dg/ext/stmtexpr26.C | 10 ++++++++++
3 files changed, 15 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/ext/stmtexpr26.C
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index 31ecbb1ac79..a150a91f2fa 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -2011,9 +2011,8 @@ strip_typedefs_expr (tree t, bool *remove_attributes,
unsigned int flags)
case LAMBDA_EXPR:
return t;
- case STATEMENT_LIST:
- error ("statement-expression in a constant expression");
- return error_mark_node;
+ case STMT_EXPR:
+ return t;
default:
break;
diff --git a/gcc/testsuite/g++.dg/eh/pr84968.C
b/gcc/testsuite/g++.dg/eh/pr84968.C
index 23c49f477a8..a6e21914eed 100644
--- a/gcc/testsuite/g++.dg/eh/pr84968.C
+++ b/gcc/testsuite/g++.dg/eh/pr84968.C
@@ -9,7 +9,9 @@ struct S {
void a()
try {
} catch (int ()
- noexcept (({ union b a; true; }))) // { dg-error "constant" }
+ noexcept (({ union b a; true; }))) // { dg-error "'b a' has
incomplete type" }
{
}
};
+
+template void S::a<int>(); // { dg-message "required from here" }
diff --git a/gcc/testsuite/g++.dg/ext/stmtexpr26.C
b/gcc/testsuite/g++.dg/ext/stmtexpr26.C
new file mode 100644
index 00000000000..498dd12ef10
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/stmtexpr26.C
@@ -0,0 +1,10 @@
+// PR c++/116418
+// { dg-do compile { target c++14 } }
+
+void foo ();
+template <typename>
+void bar ()
+{
+ decltype(auto) v = ({ foo (); 3; });
+}
+
--
2.46.0.540.g4c42d5ff28
