checker: check option propogation in multi return types

vlang · Sep 25, 2023 · f90c01d · f90c01d
1 parent 20bce37
commit f90c01d
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Showing 3 changed files with 13 additions and 0 deletions.
diff --git a/vlib/v/checker/assign.v b/vlib/v/checker/assign.v
@@ -47,6 +47,11 @@ fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 				}
 				node.right_types = right_type_sym.mr_info().types
 				right_len = node.right_types.len
+				if mut right is ast.CallExpr {
+					if right.or_block.kind == .absent && right_type.has_flag(.option) {
+						c.error("cannot multi assign as Option isn't propagated", right.pos)
+					}
+				}
 			} else if right_type == ast.void_type {
 				right_len = 0
 			}

diff --git a/vlib/v/checker/tests/multi_return_option_not_set_err.out b/vlib/v/checker/tests/multi_return_option_not_set_err.out
@@ -0,0 +1,5 @@
+vlib/v/checker/tests/multi_return_option_not_set_err.vv:1:19: error: cannot multi assign as Option isn't propagated
+    1 | a, b := 'fdf:df:'.split_once(',')
+      |                   ~~~~~~~~~~~~~~~
+    2 | println(a)
+    3 | println(b)
diff --git a/vlib/v/checker/tests/multi_return_option_not_set_err.vv b/vlib/v/checker/tests/multi_return_option_not_set_err.vv
@@ -0,0 +1,3 @@
+a, b := 'fdf:df:'.split_once(',')
+println(a)
+println(b)