C++ PATCH for c++/56464 (ICE with lambda capturing 'this' in NSDMI)

commit 92223a939da06304df678232b3f15051d750157a
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Feb 15 23:09:57 2013 -0500

    	PR c++/56464
    	PR c++/54383
    	* semantics.c (lambda_expr_this_capture): Handle NSDMI
    	and non-class scopes.

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 8038aa2..ab3d16e 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -9442,41 +9442,62 @@  lambda_expr_this_capture (tree lambda)
   if (!this_capture
       && LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) != CPLD_NONE)
     {
-      tree containing_function = TYPE_CONTEXT (LAMBDA_EXPR_CLOSURE (lambda));
-      tree lambda_stack = tree_cons (NULL_TREE, lambda, NULL_TREE);
+      tree lambda_stack = NULL_TREE;
       tree init = NULL_TREE;
 
       /* If we are in a lambda function, we can move out until we hit:
-           1. a non-lambda function,
+           1. a non-lambda function or NSDMI,
            2. a lambda function capturing 'this', or
            3. a non-default capturing lambda function.  */
-      while (LAMBDA_FUNCTION_P (containing_function))
-        {
-          tree lambda
+      for (tree tlambda = lambda; ;)
+	{
+          lambda_stack = tree_cons (NULL_TREE,
+                                    tlambda,
+                                    lambda_stack);
+
+	  if (LAMBDA_EXPR_EXTRA_SCOPE (tlambda)
+	      && TREE_CODE (LAMBDA_EXPR_EXTRA_SCOPE (tlambda)) == FIELD_DECL)
+	    {
+	      /* In an NSDMI, we don't have a function to look up the decl in,
+		 but the fake 'this' pointer that we're using for parsing is
+		 in scope_chain.  */
+	      init = scope_chain->x_current_class_ptr;
+	      gcc_checking_assert
+		(init && (TREE_TYPE (TREE_TYPE (init))
+			  == current_nonlambda_class_type ()));
+	      break;
+	    }
+
+	  tree closure_decl = TYPE_NAME (LAMBDA_EXPR_CLOSURE (tlambda));
+	  tree containing_function = decl_function_context (closure_decl);
+
+	  if (containing_function == NULL_TREE)
+	    /* We ran out of scopes; there's no 'this' to capture.  */
+	    break;
+
+	  if (!LAMBDA_FUNCTION_P (containing_function))
+	    {
+	      /* We found a non-lambda function.  */
+	      if (DECL_NONSTATIC_MEMBER_FUNCTION_P (containing_function))
+		/* First parameter is 'this'.  */
+		init = DECL_ARGUMENTS (containing_function);
+	      break;
+	    }
+
+	  tlambda
             = CLASSTYPE_LAMBDA_EXPR (DECL_CONTEXT (containing_function));
 
-          if (LAMBDA_EXPR_THIS_CAPTURE (lambda))
+          if (LAMBDA_EXPR_THIS_CAPTURE (tlambda))
 	    {
 	      /* An outer lambda has already captured 'this'.  */
-	      init = LAMBDA_EXPR_THIS_CAPTURE (lambda);
+	      init = LAMBDA_EXPR_THIS_CAPTURE (tlambda);
 	      break;
 	    }
 
-	  if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) == CPLD_NONE)
+	  if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (tlambda) == CPLD_NONE)
 	    /* An outer lambda won't let us capture 'this'.  */
 	    break;
-
-          lambda_stack = tree_cons (NULL_TREE,
-                                    lambda,
-                                    lambda_stack);
-
-          containing_function = decl_function_context (containing_function);
-        }
-
-      if (!init && DECL_NONSTATIC_MEMBER_FUNCTION_P (containing_function)
-	  && !LAMBDA_FUNCTION_P (containing_function))
-	/* First parameter is 'this'.  */
-	init = DECL_ARGUMENTS (containing_function);
+	}
 
       if (init)
 	this_capture = add_default_capture (lambda_stack,
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi1.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi1.C
new file mode 100644
index 0000000..4d16ea4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi1.C
@@ -0,0 +1,11 @@ 
+// PR c++/56464
+// { dg-do run { target c++11 } }
+
+struct bug { bug*a = [&]{ return [=]{return this;}(); }(); };
+int main()
+{
+  bug b;
+  if (b.a != &b)
+    __builtin_abort ();
+}
+
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this10.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this10.C
new file mode 100644
index 0000000..b4b8e72
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this10.C
@@ -0,0 +1,4 @@ 
+// PR c++/54383
+// { dg-do compile { target c++11 } }
+
+auto foo = [&](int a) { return a > this->b; }; // { dg-error "this" }