[BUG] Type with defined operator=: (out this, cs : int ) with lambda that capture any variable trigger assert (ICE)

[filipsajdak]

In the current implementation of cppfront (fbf55ad) the following code:

element: type = {
    operator=: (out this, cs : int) = {
        i := 42;
        :() = {
            i$; // cpp2 fail (ICE)
            // cs$; // cpp2 fail (ICE)
        };
    }
}

Trigger assert here:

cppfront/source/cppfront.cpp

Lines 2536 to 2539 in fbf55ad

	assert(
	found != n.cap_grp->members.cend()
	&& "ICE: could not find this postfix-expression in capture group"
	);

The build_capture_lambda_intro_for() function is called two times that causing cap.str and cap.str_suppressed_move contains duplicated symbol inside - the dirty fix is below patch:

diff --git a/source/cppfront.cpp b/source/cppfront.cpp
index e4c7a8b..f07f093 100644
--- a/source/cppfront.cpp
+++ b/source/cppfront.cpp
@@ -2103,8 +2103,10 @@ public:
         for (auto& cap : captures.members)
         {
             assert(cap.capture_expr->cap_grp == &captures);
+            cap.str.clear();
             print_to_string(&cap.str, *cap.capture_expr, true);
             suppress_move_from_last_use = true;
+            cap.str_suppressed_move.clear();
             print_to_string(&cap.str_suppressed_move, *cap.capture_expr, true);
             suppress_move_from_last_use = false;
         }

[hsutter]

Thanks! I believe this is now fixed, please check?

[filipsajdak]

@hsutter I confirmed it is solved!