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C++ PATCH for c++/53783 (wrong error on nested lambda)
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 03 Jul 2012 01:02:29 -0400
- Subject: C++ PATCH for c++/53783 (wrong error on nested lambda)
A nested lambda in a template was complaining about use of an 'auto'
function before its return type was deduced; this was because we were
using tsubst_copy to instantiate LAMBDA_EXPR_EXTRA_SCOPE, i.e. treating
it as an expression, which results in calling mark_used. Fixed by using
tsubst instead.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 35f50b80cc3aad10bb7ce825ff37df57d4d46450
Author: Jason Merrill <jason@redhat.com>
Date: Mon Jul 2 23:42:41 2012 -0400
PR c++/53783
* pt.c (tsubst_copy_and_build) [LAMBDA_EXPR]: Use tsubst
for LAMBDA_EXPR_EXTRA_SCOPE.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 563a1ad..d385ea7 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -14401,7 +14401,7 @@ tsubst_copy_and_build (tree t,
LAMBDA_EXPR_DISCRIMINATOR (r)
= (LAMBDA_EXPR_DISCRIMINATOR (t));
LAMBDA_EXPR_EXTRA_SCOPE (r)
- = RECUR (LAMBDA_EXPR_EXTRA_SCOPE (t));
+ = tsubst (LAMBDA_EXPR_EXTRA_SCOPE (t), args, complain, in_decl);
LAMBDA_EXPR_RETURN_TYPE (r)
= tsubst (LAMBDA_EXPR_RETURN_TYPE (t), args, complain, in_decl);
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template7.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template7.C
new file mode 100644
index 0000000..5b098d0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-template7.C
@@ -0,0 +1,5 @@
+// PR c++/53783
+// { dg-do compile { target c++11 } }
+
+template <class T> void foo() { [] { [] {}; }; }
+int main() { foo<void>(); }