checker: check fixed array init with default expression (#19472)

vlib/v/checker/containers.v

@@ -62,15 +62,7 @@ fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 			}
 		}
 		if node.has_default {
-			mut default_expr := node.default_expr
+			c.check_array_init_default_expr(mut node)
-			default_typ := c.check_expr_opt_call(default_expr, c.expr(mut 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(mut node.len_expr))
@@ -304,12 +296,22 @@ fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 			node.typ = ast.new_type(idx)
 		}
 		if node.has_default {
-			node.default_type = c.expr(mut node.default_expr)
+			c.check_array_init_default_expr(mut node)
 		}
 	}
 	return node.typ
 }
 
+fn (mut c Checker) check_array_init_default_expr(mut node ast.ArrayInit) {
+	mut default_expr := node.default_expr
+	default_typ := c.check_expr_opt_call(default_expr, c.expr(mut 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()) }
+}
+
 fn (mut c Checker) check_array_init_para_type(para string, mut expr ast.Expr, pos token.Pos) {
 	sym := c.table.sym(c.unwrap_generic(c.expr(mut expr)))
 	if sym.kind !in [.int, .int_literal] {

vlib/v/checker/tests/fixed_array_init_with_default.out

@@ -0,0 +1,27 @@
+vlib/v/checker/tests/fixed_array_init_with_default.vv:6:27: error: expected `string`, not `[]string`
+    4 |
+    5 | fn main() {
+    6 |     _ := Foo{[2]string{init: ['a', 'b']}}
+      |                              ~~~~~~~~~~
+    7 |     _ := Foo{[2]string{init: 2.2}}
+    8 |     _ := Foo{[2]string{init: 22}}
+vlib/v/checker/tests/fixed_array_init_with_default.vv:7:27: error: expected `string`, not `float literal`
+    5 | fn main() {
+    6 |     _ := Foo{[2]string{init: ['a', 'b']}}
+    7 |     _ := Foo{[2]string{init: 2.2}}
+      |                              ~~~
+    8 |     _ := Foo{[2]string{init: 22}}
+    9 |     _ := Foo{[2]string{init: true}}
+vlib/v/checker/tests/fixed_array_init_with_default.vv:8:27: error: expected `string`, not `int literal`
+    6 |     _ := Foo{[2]string{init: ['a', 'b']}}
+    7 |     _ := Foo{[2]string{init: 2.2}}
+    8 |     _ := Foo{[2]string{init: 22}}
+      |                              ~~
+    9 |     _ := Foo{[2]string{init: true}}
+   10 | }
+vlib/v/checker/tests/fixed_array_init_with_default.vv:9:27: error: expected `string`, not `bool`
+    7 |     _ := Foo{[2]string{init: 2.2}}
+    8 |     _ := Foo{[2]string{init: 22}}
+    9 |     _ := Foo{[2]string{init: true}}
+      |                              ~~~~
+   10 | }

vlib/v/checker/tests/fixed_array_init_with_default.vv

@@ -0,0 +1,10 @@
+struct Foo {
+	stack_arr [2]string
+}
+
+fn main() {
+	_ := Foo{[2]string{init: ['a', 'b']}}
+	_ := Foo{[2]string{init: 2.2}}
+	_ := Foo{[2]string{init: 22}}
+	_ := Foo{[2]string{init: true}}
+}

vlib/v/checker/tests/option_fn_err.out

@@ -3,21 +3,21 @@ vlib/v/checker/tests/option_fn_err.vv:34:16: error: cannot use `?int` as `int`,
    33 |     _ := bar(0)
    34 |     println(twice(bar(0)))
       |                   ~~~~~~
-   35 | 
+   35 |
    36 |     // anon fn
 vlib/v/checker/tests/option_fn_err.vv:37:16: error: cannot use `?int` as `int`, it must be unwrapped first in argument 1 to `anon`
-   35 | 
+   35 |
    36 |     // anon fn
    37 |     fn (_ int) {}(bar(0))
       |                   ~~~~~~
-   38 | 
+   38 |
    39 |     // assert
 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{
@@ -38,7 +38,7 @@ vlib/v/checker/tests/option_fn_err.vv:49:6: error: cannot use `?int` as `int`, i
    48 |     v.add(bar(0)) // call method
    49 |     v.f(bar(0)) // call fn field
       |         ~~~~~~
-   50 | 
+   50 |
    51 |     // array
 vlib/v/checker/tests/option_fn_err.vv:56:27: error: cannot use unwrapped Option as initializer
    54 |     // init
@@ -47,6 +47,13 @@ vlib/v/checker/tests/option_fn_err.vv:56:27: error: cannot use unwrapped Option
       |                              ~~~~~~
    57 |     _ := [bar(0)]!
    58 |     _ := [1]int{init: bar(0)}
+vlib/v/checker/tests/option_fn_err.vv:58:20: error: cannot use unwrapped Option as initializer
+   56 |     _ := []int{len: 1, init: bar(0)}
+   57 |     _ := [bar(0)]!
+   58 |     _ := [1]int{init: bar(0)}
+      |                       ~~~~~~
+   59 |     // index
+   60 |     println(arr[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
@@ -101,5 +108,5 @@ 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) {