checker: fix missing check for initializer with function returning options (#17820)

Author: felipensp

vlib/v/checker/containers.v

@@ -66,11 +66,18 @@ fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 			default_expr := node.default_expr
 			default_typ := c.check_expr_opt_call(default_expr, c.expr(default_expr))
 			node.default_type = default_typ
+			if !node.elem_type.has_flag(.option) && default_typ.has_flag(.option) {
+				c.error('cannot use unwrapped Option as initializer', default_expr.pos())
+			}
 			c.check_expected(default_typ, node.elem_type) or {
 				c.error(err.msg(), default_expr.pos())
 			}
 		}
 		if node.has_len {
+			len_typ := c.check_expr_opt_call(node.len_expr, c.expr(node.len_expr))
+			if len_typ.has_flag(.option) {
+				c.error('cannot use unwrapped Option as length', node.len_expr.pos())
+			}
 			if node.has_len && !node.has_default {
 				elem_type_sym := c.table.sym(node.elem_type)
 				if elem_type_sym.kind == .interface_ {

vlib/v/checker/tests/array_init_option_err.out

@@ -0,0 +1,20 @@
+vlib/v/checker/tests/array_init_option_err.vv:2:38: error: cannot use unwrapped Option as initializer
+    1 | fn main() {
+    2 |     mut arr1 := []int{len: get(), init: get()}
+      |                                         ~~~~~
+    3 |     dump(arr1)
+    4 |
+vlib/v/checker/tests/array_init_option_err.vv:5:20: error: cannot use unwrapped Option as length
+    3 |     dump(arr1)
+    4 | 
+    5 |     arr1 = []int{len: get(), init: get()?}
+      |                       ~~~~~
+    6 |     dump(arr1)
+    7 |
+vlib/v/checker/tests/array_init_option_err.vv:8:34: error: cannot use unwrapped Option as initializer
+    6 |     dump(arr1)
+    7 | 
+    8 |     arr1 = []int{len: get()?, init: get()}
+      |                                     ~~~~~
+    9 |     dump(arr1)
+   10 | }

vlib/v/checker/tests/array_init_option_err.vv

@@ -0,0 +1,14 @@
+fn main() {
+	mut arr1 := []int{len: get(), init: get()}
+	dump(arr1)
+
+	arr1 = []int{len: get(), init: get()?}
+	dump(arr1)
+
+	arr1 = []int{len: get()?, init: get()}
+	dump(arr1)
+}
+
+fn get() ?int {
+	return 5
+}

vlib/v/checker/tests/option_fn_err.out

@@ -1,9 +1,9 @@
 vlib/v/checker/tests/option_fn_err.vv:40:9: error: assert can be used only with `bool` expressions, but found `bool` instead
-   38 |
+   38 | 
    39 |     // assert
    40 |     assert bar(true)
       |            ~~~~~~~~~
-   41 |
+   41 | 
    42 |     // struct
 vlib/v/checker/tests/option_fn_err.vv:45:3: error: cannot assign an Option value to a non-option struct field
    43 |     mut v := Data{
@@ -12,6 +12,13 @@ vlib/v/checker/tests/option_fn_err.vv:45:3: error: cannot assign an Option value
       |         ~~~~~~~~~~~~~
    46 |         opt: bar(0)
    47 |     }
+vlib/v/checker/tests/option_fn_err.vv:56:27: error: cannot use unwrapped Option as initializer
+   54 |     // init
+   55 |     _ := [bar(0)]
+   56 |     _ := []int{len: 1, init: bar(0)}
+      |                              ~~~~~~
+   57 |     _ := [bar(0)]!
+   58 |     _ := [1]int{init: bar(0)}
 vlib/v/checker/tests/option_fn_err.vv:60:13: error: cannot use Option or Result as index (array type `[]int`)
    58 |     _ := [1]int{init: bar(0)}
    59 |     // index
@@ -38,5 +45,5 @@ vlib/v/checker/tests/option_fn_err.vv:69:18: error: type mismatch, `bar` must re
    68 |     println(arr.any(bar(true)))
    69 |     println(arr.all(bar(true)))
       |                     ~~~~~~~~~
-   70 |
+   70 | 
    71 |     match bar(0) {