1 files changed, 26 insertions, 2 deletions

diff --git a/src/check_stmt.cpp b/src/check_stmt.cpp
index 388a64e00..bdfa24460 100644
--- a/src/check_stmt.cpp
+++ b/src/check_stmt.cpp
@@ -402,6 +402,12 @@ gb_internal Type *check_assignment_variable(CheckerContext *ctx, Operand *lhs, O
 
 	Type *assignment_type = lhs->type;
 
+	if (rhs->mode == Addressing_Type && is_type_polymorphic(rhs->type)) {
+		gbString t = type_to_string(rhs->type);
+		error(rhs->expr, "Invalid use of a non-specialized polymorphic type '%s'", t);
+		gb_string_free(t);
+	}
+
 	switch (lhs->mode) {
 	case Addressing_Invalid:
 		return nullptr;
@@ -1455,6 +1461,7 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 	bool is_map = false;
 	bool use_by_reference_for_value = false;
 	bool is_soa = false;
+	bool is_reverse = rs->reverse;
 
 	Ast *expr = unparen_expr(rs->expr);
 
@@ -1470,6 +1477,10 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 		}
 		array_add(&vals, x.type);
 		array_add(&vals, t_int);
+
+		if (is_reverse) {
+			error(node, "#reverse for is not supported with ranges, prefer an explicit for loop with init, condition, and post arguments");
+		}
 	} else {
 		Operand operand = {Addressing_Invalid};
 		check_expr_base(ctx, &operand, expr, nullptr);
@@ -1482,6 +1493,9 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 				gb_string_free(t);
 				goto skip_expr_range_stmt;
 			} else {
+				if (is_reverse) {
+					error(node, "#reverse for is not supported for enum types");
+				}
 				array_add(&vals, operand.type);
 				array_add(&vals, t_int);
 				add_type_info_type(ctx, operand.type);
@@ -1495,7 +1509,11 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 				if (is_type_string(t) && t->Basic.kind != Basic_cstring) {
 					array_add(&vals, t_rune);
 					array_add(&vals, t_int);
-					add_package_dependency(ctx, "runtime", "string_decode_rune");
+					if (is_reverse) {
+						add_package_dependency(ctx, "runtime", "string_decode_last_rune");
+					} else {
+						add_package_dependency(ctx, "runtime", "string_decode_rune");
+					}
 				}
 				break;
 
@@ -1528,6 +1546,9 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 				is_map = true;
 				array_add(&vals, t->Map.key);
 				array_add(&vals, t->Map.value);
+				if (is_reverse) {
+					error(node, "#reverse for is not supported for map types, as maps are unordered");
+				}
 				break;
 
 			case Type_Tuple:
@@ -1564,6 +1585,9 @@ gb_internal void check_range_stmt(CheckerContext *ctx, Ast *node, u32 mod_flags)
 						break;
 					}
 
+					if (is_reverse) {
+						error(node, "#reverse for is not supported for multiple return valued parameters");
+					}
 				}
 				break;
 
@@ -2170,7 +2194,7 @@ gb_internal void check_return_stmt(CheckerContext *ctx, Ast *node) {
 	auto operands = array_make<Operand>(heap_allocator(), 0, 2*rs->results.count);
 	defer (array_free(&operands));
 
-	check_unpack_arguments(ctx, result_entities, result_count, &operands, rs->results, true, false);
+	check_unpack_arguments(ctx, result_entities, result_count, &operands, rs->results, UnpackFlag_AllowOk);
 
 	if (result_count == 0 && rs->results.count > 0) {
 		error(rs->results[0], "No return values expected");