re PR c++/55223 ([C++11] Default lambda expression of a templated class member)

	PR c++/55223
gcc/cp/
	* pt.c (tsubst_copy_and_build) [LAMBDA_EXPR]: Fix handling of
	default argument scope.
	* mangle.c (write_name): Likewise.
libiberty/
	* cp-demangle.c (d_dump): Handle DEMANGLE_COMPONENT_DEFAULT_ARG.
	(d_print_comp): Likewise.

From-SVN: r196065

5 files changed, 43 insertions, 4 deletions

diff --git a/gcc/common.opt b/gcc/common.opt
index b6592e0..3c7b415 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -785,7 +785,8 @@ Driver Undocumented
 ;    argument.
 ;    First selectable in G++ 4.7.
 ;
-; 7: The version of the ABI that treats nullptr_t as a builtin type.
+; 7: The version of the ABI that treats nullptr_t as a builtin type and
+;    corrects the mangling of lambdas in default argument scope.
 ;    First selectable in G++ 4.8.
 ; Additional positive integers will be assigned as new versions of
 ; the ABI become the default version of the ABI.
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4784a3c..de03a7a 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,10 @@
 2013-02-14  Jason Merrill  <jason@redhat.com>
 
+	PR c++/55223
+	* pt.c (tsubst_copy_and_build) [LAMBDA_EXPR]: Fix handling of
+	default argument scope.
+	* mangle.c (write_name): Likewise.
+
 	PR c++/55232
 	* error.c (find_typenames_r): Don't walk into a pack expansion.
 
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index f6b3443..a48d4768 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -802,7 +802,10 @@ write_name (tree decl, const int ignore_local_scope)
   if (context == NULL
       || context == global_namespace
       || DECL_NAMESPACE_STD_P (context)
-      || (ignore_local_scope && TREE_CODE (context) == FUNCTION_DECL))
+      || (ignore_local_scope
+	  && (TREE_CODE (context) == FUNCTION_DECL
+	      || (abi_version_at_least (7)
+		  && TREE_CODE (context) == PARM_DECL))))
     {
       tree template_info;
       /* Is this a template instance?  */
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index bd44fde..aa868a4 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -14444,8 +14444,20 @@ tsubst_copy_and_build (tree t,
 	   than build a new one.  */
 	tree scope = LAMBDA_EXPR_EXTRA_SCOPE (t);
 	if (scope && TREE_CODE (scope) == FUNCTION_DECL)
-	  scope = tsubst (LAMBDA_EXPR_EXTRA_SCOPE (t), args,
-			  complain, in_decl);
+	  scope = tsubst (scope, args, complain, in_decl);
+	else if (scope && TREE_CODE (scope) == PARM_DECL)
+	  {
+	    /* Look up the parameter we want directly, as tsubst_copy
+	       doesn't do what we need.  */
+	    tree fn = tsubst (DECL_CONTEXT (scope), args, complain, in_decl);
+	    tree parm = FUNCTION_FIRST_USER_PARM (fn);
+	    while (DECL_PARM_INDEX (parm) != DECL_PARM_INDEX (scope))
+	      parm = DECL_CHAIN (parm);
+	    scope = parm;
+	    /* FIXME Work around the parm not having DECL_CONTEXT set.  */
+	    if (DECL_CONTEXT (scope) == NULL_TREE)
+	      DECL_CONTEXT (scope) = fn;
+	  }
 	else
 	  scope = RECUR (scope);
 	LAMBDA_EXPR_EXTRA_SCOPE (r) = scope;
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg3.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg3.C
new file mode 100644
index 0000000..f02fb29
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-defarg3.C
@@ -0,0 +1,18 @@
+// PR c++/55223
+// { dg-options "-std=c++11 -fabi-version=0" }
+// { dg-final { scan-assembler "_ZN8functionC1IZN1CIiE4testES_Ed_UliE_EET_" } }
+
+struct function
+{
+  template <class U> function(U u) { }
+};
+
+template<typename T> struct C
+{
+  static T test(function f = [](int i){return i;}) { }
+};
+
+int main()
+{
+  C<int>::test();
+}