checker: fix comptime selector evaluate when checked against type of array (#18774)

vlib/v/checker/comptime.v

@@ -742,11 +742,9 @@ fn (mut c Checker) comptime_if_branch(cond ast.Expr, pos token.Pos) ComptimeBran
 					}
 				}
 				.key_in, .not_in {
-					if cond.left is ast.Ident {
-						c.expr(cond.left)
-					}
 					if cond.left in [ast.TypeNode, ast.SelectorExpr, ast.Ident]
 						&& cond.right is ast.ArrayInit {
+						c.expr(cond.left)
 						for expr in cond.right.exprs {
 							if expr !in [ast.ComptimeType, ast.TypeNode] {
 								c.error('invalid `\$if` condition, only types are allowed',

vlib/v/gen/c/comptime.v

@@ -796,6 +796,11 @@ fn (mut g Gen) get_comptime_var_type(node ast.Expr) ast.Type {
 fn (mut g Gen) resolve_comptime_type(node ast.Expr, default_type ast.Type) ast.Type {
 	if (node is ast.Ident && g.is_comptime_var(node)) || node is ast.ComptimeSelector {
 		return g.get_comptime_var_type(node)
+	} else if node is ast.SelectorExpr {
+		sym := g.table.sym(g.unwrap_generic(node.expr_type))
+		if f := g.table.find_field_with_embeds(sym, node.field_name) {
+			return f.typ
+		}
 	}
 	return default_type
 }

vlib/v/tests/comptime_arr_type_test.v

@@ -0,0 +1,24 @@
+struct TestStruct {
+	test string
+}
+
+fn test[T](val T) string {
+	$if T is $struct {
+		$for attribute in T.fields {
+			$if attribute.name == 'test' {
+				$if val.test in [u32, i32, $int] {
+					return 'struct field ${typeof(val.test).name}'
+				} $else {
+					return 'got type: ${typeof(val.test).name}'
+				}
+			}
+		}
+		return 'no test field in struct'
+	} $else {
+		return 'empty'
+	}
+}
+
+fn test_main() {
+	assert test(TestStruct{'7'}) == 'got type: string'
+}

vlib/v/tests/comptime_selector_member_test.v

@@ -0,0 +1,36 @@
+struct OtherStruct {
+	test string
+}
+
+struct I32Struct {
+	test i32
+}
+
+struct U32Struct {
+	test u32
+}
+
+fn test[T](val T) string {
+	$if val is $struct {
+		println(T.name)
+		$for attribute in T.fields {
+			$if attribute.name == 'test' {
+				$if val.test in [u32, i32] {
+					return 'struct field ${typeof(val.test).name}'
+				} $else {
+					return 'not u32 or i32 struct field, got type: ${typeof(val.test).name}'
+				}
+			}
+		}
+		return 'no test field in struct'
+	} $else {
+		return 'else block'
+	}
+}
+
+fn test_main() {
+	assert test(u32(7)) == 'else block'
+	assert test(OtherStruct{'7'}) == 'struct field string'
+	assert test(I32Struct{-7}) == 'struct field i32'
+	assert test(U32Struct{7}) == 'struct field u32'
+}

vlib/v/tests/for_smartcast_test.v

@@ -16,7 +16,7 @@ fn test_nested_sumtype_selector() {
 		pos: 1
 	}))}
 	for c.node is Expr {
-		assert typeof(c.node).name == 'Expr'
+		assert typeof(c.node).name == 'Node'
 		break
 	}
 }