From bc03ae6217562b35c956d289e78c1a0c14d3b190 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 15 Apr 2026 02:55:56 +0300
Subject: [PATCH] all: refactor typeof(expr) feature (fixes #20387)

---
 vlib/v/checker/checker.v                        |  2 +-
 vlib/v/gen/c/cgen.v                             |  5 +++--
 vlib/v/gen/js/js.v                              |  2 +-
 vlib/v/tests/generics/generic_typeof_idx_test.v | 11 +++++++++++
 vlib/v/tests/typeof_test.v                      |  9 +++++++++
 vlib/v/type_resolver/comptime_resolver.v        |  2 +-
 6 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 10b8772b4..b2a638258 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -2711,7 +2711,7 @@ fn (mut c Checker) selector_expr(mut node ast.SelectorExpr) ast.Type {
 			else {
 				if node.field_name == 'name' {
 					return ast.string_type
-				} else if node.field_name in ['idx', 'unaliased_typ', 'key_type', 'value_type',
+				} else if node.field_name in ['idx', 'typ', 'unaliased_typ', 'key_type', 'value_type',
 					'element_type'] {
 					return ast.int_type
 				} else if node.field_name == 'indirections' {
diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index d1fb043b1..e99506e0f 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -5687,8 +5687,9 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 					}
 					g.type_name(name_type)
 					return
-				} else if node.field_name in ['idx', 'unaliased_typ'] {
-					// `T.idx`, `T.unaliased_typ`, `typeof(expr).idx`, `typeof(expr).unalised_typ`
+				} else if node.field_name in ['idx', 'typ', 'unaliased_typ'] {
+					// `T.idx`, `T.typ`, `T.unaliased_typ`, `typeof(expr).idx`, `typeof(expr).typ`,
+					// `typeof(expr).unalised_typ`
 					mut name_type := node.name_type
 					if node.expr is ast.TypeOf {
 						if g.cur_fn != unsafe { nil } && g.cur_concrete_types.len > 0 {
diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index df8775aa7..fda63a852 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -3484,7 +3484,7 @@ fn (mut g JsGen) gen_selector_expr(it ast.SelectorExpr) {
 				if node.field_name == 'name' {
 					g.type_name(it.name_type)
 					return
-				} else if node.field_name == 'idx' {
+				} else if node.field_name in ['idx', 'typ'] {
 					g.write('new int(')
 					g.write('${int(g.unwrap_generic(it.name_type))}')
 					g.write(')')
diff --git a/vlib/v/tests/generics/generic_typeof_idx_test.v b/vlib/v/tests/generics/generic_typeof_idx_test.v
index 89c529f6d..01093202e 100644
--- a/vlib/v/tests/generics/generic_typeof_idx_test.v
+++ b/vlib/v/tests/generics/generic_typeof_idx_test.v
@@ -25,12 +25,23 @@ fn idx[T](a [][]T) int {
 	return 0
 }
 
+fn typ[T](a [][]T) int {
+	$if typeof[T]().typ is $int {
+		return 1
+	} $else $if typeof[T]().typ is $string {
+		return 2
+	}
+	return 0
+}
+
 fn test_main() {
 	a := Foo{
 		a: [1, 2, 3]
 	}
 	assert idx([a.a]) == 1
 	assert idx([['']]) == 2
+	assert typ([a.a]) == 1
+	assert typ([['']]) == 2
 
 	assert unaliased_typ(1) == 1
 	assert unaliased_typ('') == 2
diff --git a/vlib/v/tests/typeof_test.v b/vlib/v/tests/typeof_test.v
index fda9c1763..b3bd92670 100644
--- a/vlib/v/tests/typeof_test.v
+++ b/vlib/v/tests/typeof_test.v
@@ -202,3 +202,12 @@ fn test_variadic_type() {
 	assert variadic_bool(true, false) == '...bool'
 	assert variadic_f64(3.1, 3.2) == '...f64'
 }
+
+fn test_typeof_typ_field() {
+	a := 123
+	b := &a
+	assert typeof(a).typ == typeof(a).idx
+	assert typeof(a).typ == typeof[int]().idx
+	assert typeof(b).typ == typeof(b).idx
+	assert typeof[FooBar]().typ == typeof[FooBar]().idx
+}
diff --git a/vlib/v/type_resolver/comptime_resolver.v b/vlib/v/type_resolver/comptime_resolver.v
index 3fa4261ab..54e5f052e 100644
--- a/vlib/v/type_resolver/comptime_resolver.v
+++ b/vlib/v/type_resolver/comptime_resolver.v
@@ -138,7 +138,7 @@ pub fn (mut t TypeResolver) typeof_field_type(typ ast.Type, field_name string) a
 		'name' {
 			return ast.string_type
 		}
-		'idx' {
+		'idx', 'typ' {
 			return t.resolver.unwrap_generic(typ)
 		}
 		'unaliased_typ' {
-- 
2.39.5