Correct parapoly determination of generated internal type of a `map`

1 files changed, 7 insertions, 1 deletions

diff --git a/src/check_expr.cpp b/src/check_expr.cpp
index 196982084..3f4f11813 100644
--- a/src/check_expr.cpp
+++ b/src/check_expr.cpp
@@ -1360,7 +1360,13 @@ bool is_polymorphic_type_assignable(CheckerContext *c, Type *poly, Type *source,
 		if (source->kind == Type_Map) {
 			bool key   = is_polymorphic_type_assignable(c, poly->Map.key, source->Map.key, true, modify_type);
 			bool value = is_polymorphic_type_assignable(c, poly->Map.value, source->Map.value, true, modify_type);
-			return key || value;
+			if (key || value) {
+				poly->Map.entry_type = nullptr;
+				poly->Map.internal_type = nullptr;
+				poly->Map.lookup_result_type = nullptr;
+				init_map_internal_types(poly);
+				return true;
+			}
 		}
 		return false;