v2: fix all tests

Author: medvednikov

vlib/v2/builder/parse_parallel.v

@@ -3124,14 +3124,16 @@ fn (mut t Transformer) try_transform_map_index_push(stmt ast.ExprStmt) ?ast.Stmt
 		}))
 	})
 
-	// Common: (array*)map__get_and_set(&m, &key, &empty_array)
+	// Common: (array*)map__get(&m, &key, &empty_array)
+	// Use map__get (not map__get_and_set) so that pushing to a missing key is a no-op:
+	// map__get returns a pointer to the existing value or to the zero value without inserting.
 	arr_ptr_expr := ast.Expr(ast.CastExpr{
 		typ:  ast.Ident{
 			name: 'array*'
 		}
 		expr: ast.CallExpr{
 			lhs:  ast.Ident{
-				name: 'map__get_and_set'
+				name: 'map__get'
 			}
 			args: [
 				map_arg,

vlib/v2/transformer/transformer.v

@@ -2217,10 +2217,12 @@ fn (mut c Checker) sync_imported_const_type(source Const) {
 		for _, scope_ptr in c.env.scopes {
 			mut scope := unsafe { scope_ptr }
 			obj := scope.objects[source.name] or { continue }
-			if obj is Const && obj.mod == source.mod {
-				mut updated := obj
-				updated.typ = source.typ
-				scope.objects[source.name] = Object(updated)
+			if obj is Const {
+				if obj.mod == source.mod {
+					mut updated := obj
+					updated.typ = source.typ
+					scope.objects[source.name] = Object(updated)
+				}
 			}
 		}
 	}

vlib/v2/types/checker.v

@@ -404,7 +404,7 @@ fn value_type_with_depth(t Type, depth int) Type {
 			if elem_type := t.elem_type {
 				return elem_type
 			}
-			return Type(Channel{})
+			return Type(empty_channel())
 		} // TODO: ?
 		Map {
 			return t.value_type
@@ -427,7 +427,7 @@ fn value_type_with_depth(t Type, depth int) Type {
 			if elem_type := t.elem_type {
 				return elem_type
 			}
-			return Type(Thread{})
+			return Type(empty_thread())
 		} // TODO: ?
 		OptionType, ResultType {
 			return value_type_with_depth(t.base_type, depth + 1)