checker, cgen: fix the comparison of alias and non-alias values (#19112)

vlib/v/checker/infix.v

@@ -147,14 +147,7 @@ fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 	match node.op {
 		// .eq, .ne, .gt, .lt, .ge, .le, .and, .logical_or, .dot, .key_as, .right_shift {}
 		.eq, .ne {
-			is_mismatch :=
+			if left_type in ast.integer_type_idxs && right_type in ast.integer_type_idxs {
-				(left_sym.kind == .alias && right_sym.kind in [.struct_, .array, .sum_type])
-				|| (right_sym.kind == .alias && left_sym.kind in [.struct_, .array, .sum_type])
-			if is_mismatch {
-				c.add_error_detail('left type: `${c.table.type_to_str(left_type)}` vs right type: `${c.table.type_to_str(right_type)}`')
-				c.error('possible type mismatch of compared values of `${node.op}` operation',
-					left_right_pos)
-			} else if left_type in ast.integer_type_idxs && right_type in ast.integer_type_idxs {
 				is_left_type_signed := left_type in ast.signed_integer_type_idxs
 				is_right_type_signed := right_type in ast.signed_integer_type_idxs
 				if !is_left_type_signed && mut node.right is ast.IntegerLiteral {

vlib/v/checker/tests/alias_array_possible_type_mismatch.out

@@ -1,8 +0,0 @@
-vlib/v/checker/tests/alias_array_possible_type_mismatch.vv:11:7: error: possible type mismatch of compared values of `==` operation
-    9 |     mut a := new_vector(12, 4.5, 6.7, 6)
-   10 |     dump(a)
-   11 |     x := a == []f64{}
-      |          ~~~~~~~~~~~
-   12 |     dump(x)
-   13 | }
-Details: left type: `main.Vector` vs right type: `[]f64`

vlib/v/checker/tests/alias_array_possible_type_mismatch.vv

@@ -1,13 +0,0 @@
-type Vector = []f64
-type Another = []f64
-
-fn new_vector(x f64, y f64, z f64, w f64) Vector {
-	return Vector([x, y, z, w])
-}
-
-fn test_alias_array_plus_overload() {
-	mut a := new_vector(12, 4.5, 6.7, 6)
-	dump(a)
-	x := a == []f64{}
-	dump(x)
-}

vlib/v/checker/tests/comparing_typesymbol_to_a_type_should_not_compile.out

@@ -1,8 +1,7 @@
-vlib/v/checker/tests/comparing_typesymbol_to_a_type_should_not_compile.vv:12:7: error: possible type mismatch of compared values of `==` operation
+vlib/v/checker/tests/comparing_typesymbol_to_a_type_should_not_compile.vv:12:7: error: infix expr: cannot use `v.ast.Type` (right expression) as `v.ast.TypeSymbol`
    10 |     x := ityp == ast.string_type
    11 |     // the next line should produce at least a warning, or even an error, without an explicit cast:
    12 |     z := isym == ast.string_type
       |          ~~~~~~~~~~~~~~~~~~~~~~~
    13 |     println(typeof(isym).name)
    14 |     println(typeof(ast.string_type).name)
-Details: left type: `&ast.TypeSymbol` vs right type: `ast.Type`

vlib/v/checker/tests/eq_ne_op_wrong_type_err.out

@@ -1,5 +1,5 @@
 vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:12:10: error: infix expr: cannot use `int literal` (right expression) as `Aaa`
-   10 | 
+   10 |
    11 | fn main() {
    12 |     println(Aaa{} == 10)
       |             ~~~~~~~~~~~
@@ -24,113 +24,45 @@ vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:15:10: error: infix expr: cannot
    14 |     println(Aaa{} != 10)
    15 |     println(10 != Aaa{})
       |             ~~~~~~~~~~~
-   16 | 
+   16 |
    17 |     println(Aaa{0} == AAaa{0})
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:17:10: error: possible type mismatch of compared values of `==` operation
+vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:29:10: error: infix expr: cannot use `Arr` (right expression) as `ArrAaa`
-   15 |     println(10 != Aaa{})
-   16 | 
-   17 |     println(Aaa{0} == AAaa{0})
-      |             ~~~~~~~~~~~~~~~~~
-   18 |     println(AAaa{0} == Aaa{0})
-   19 |     println(AAaa{1} != Aaa{1})
-Details: left type: `main.Aaa` vs right type: `main.AAaa`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:18:10: error: possible type mismatch of compared values of `==` operation
-   16 | 
-   17 |     println(Aaa{0} == AAaa{0})
-   18 |     println(AAaa{0} == Aaa{0})
-      |             ~~~~~~~~~~~~~~~~~
-   19 |     println(AAaa{1} != Aaa{1})
-   20 |     println(Aaa{1} != AAaa{1})
-Details: left type: `main.AAaa` vs right type: `main.Aaa`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:19:10: error: possible type mismatch of compared values of `!=` operation
-   17 |     println(Aaa{0} == AAaa{0})
-   18 |     println(AAaa{0} == Aaa{0})
-   19 |     println(AAaa{1} != Aaa{1})
-      |             ~~~~~~~~~~~~~~~~~
-   20 |     println(Aaa{1} != AAaa{1})
-   21 |
-Details: left type: `main.AAaa` vs right type: `main.Aaa`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:20:10: error: possible type mismatch of compared values of `!=` operation
-   18 |     println(AAaa{0} == Aaa{0})
-   19 |     println(AAaa{1} != Aaa{1})
-   20 |     println(Aaa{1} != AAaa{1})
-      |             ~~~~~~~~~~~~~~~~~
-   21 | 
-   22 |     arr := Arr([0])
-Details: left type: `main.Aaa` vs right type: `main.AAaa`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:23:10: error: possible type mismatch of compared values of `==` operation
-   21 | 
-   22 |     arr := Arr([0])
-   23 |     println(arr == [0])
-      |             ~~~~~~~~~~
-   24 |     println([1] == arr)
-   25 |     println(arr != [0])
-Details: left type: `main.Arr` vs right type: `[]int`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:24:10: error: possible type mismatch of compared values of `==` operation
-   22 |     arr := Arr([0])
-   23 |     println(arr == [0])
-   24 |     println([1] == arr)
-      |             ~~~~~~~~~~
-   25 |     println(arr != [0])
-   26 |     println([1] != arr)
-Details: left type: `[]int` vs right type: `main.Arr`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:25:10: error: possible type mismatch of compared values of `!=` operation
-   23 |     println(arr == [0])
-   24 |     println([1] == arr)
-   25 |     println(arr != [0])
-      |             ~~~~~~~~~~
-   26 |     println([1] != arr)
    27 |
-Details: left type: `main.Arr` vs right type: `[]int`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:26:10: error: possible type mismatch of compared values of `!=` operation
-   24 |     println([1] == arr)
-   25 |     println(arr != [0])
-   26 |     println([1] != arr)
-      |             ~~~~~~~~~~
-   27 | 
-   28 |     arr_aaa := ArrAaa(arr)
-Details: left type: `[]int` vs right type: `main.Arr`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:29:10: error: possible type mismatch of compared values of `==` operation
-   27 | 
    28 |     arr_aaa := ArrAaa(arr)
    29 |     println(arr_aaa == arr)
       |             ~~~~~~~~~~~~~~
    30 |     println(arr == arr_aaa)
    31 |     println(arr_aaa != arr)
-Details: left type: `main.ArrAaa` vs right type: `main.Arr`
+vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:30:10: error: infix expr: cannot use `ArrAaa` (right expression) as `Arr`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:30:10: error: possible type mismatch of compared values of `==` operation
    28 |     arr_aaa := ArrAaa(arr)
    29 |     println(arr_aaa == arr)
    30 |     println(arr == arr_aaa)
       |             ~~~~~~~~~~~~~~
    31 |     println(arr_aaa != arr)
    32 |     println(arr != arr_aaa)
-Details: left type: `main.Arr` vs right type: `main.ArrAaa`
+vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:31:10: error: infix expr: cannot use `Arr` (right expression) as `ArrAaa`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:31:10: error: possible type mismatch of compared values of `!=` operation
    29 |     println(arr_aaa == arr)
    30 |     println(arr == arr_aaa)
    31 |     println(arr_aaa != arr)
       |             ~~~~~~~~~~~~~~
    32 |     println(arr != arr_aaa)
    33 |
-Details: left type: `main.ArrAaa` vs right type: `main.Arr`
+vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:32:10: error: infix expr: cannot use `ArrAaa` (right expression) as `Arr`
-vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:32:10: error: possible type mismatch of compared values of `!=` operation
    30 |     println(arr == arr_aaa)
    31 |     println(arr_aaa != arr)
    32 |     println(arr != arr_aaa)
       |             ~~~~~~~~~~~~~~
-   33 | 
+   33 |
    34 |     println(arr_aaa == [0])
-Details: left type: `main.Arr` vs right type: `main.ArrAaa`
 vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:34:10: error: infix expr: cannot use `[]int` (right expression) as `ArrAaa`
    32 |     println(arr != arr_aaa)
-   33 | 
+   33 |
    34 |     println(arr_aaa == [0])
       |             ~~~~~~~~~~~~~~
    35 |     println([1] == arr_aaa)
    36 |     println(arr_aaa != [0])
 vlib/v/checker/tests/eq_ne_op_wrong_type_err.vv:35:10: error: infix expr: cannot use `ArrAaa` (right expression) as `[]int`
-   33 | 
+   33 |
    34 |     println(arr_aaa == [0])
    35 |     println([1] == arr_aaa)
       |             ~~~~~~~~~~~~~~

vlib/v/gen/c/infix.v

@@ -148,13 +148,18 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 		}
 		g.expr(node.right)
 		g.write(')')
-	} else if left.typ.idx() == right.typ.idx()
+	} else if left.unaliased.idx() == right.unaliased.idx()
 		&& left.sym.kind in [.array, .array_fixed, .alias, .map, .struct_, .sum_type, .interface_] {
 		if g.pref.translated && !g.is_builtin_mod {
 			g.gen_plain_infix_expr(node)
 			return
 		}
-		match left.sym.kind {
+		kind := if left.sym.kind == .alias && right.sym.kind != .alias {
+			left.unaliased_sym.kind
+		} else {
+			left.sym.kind
+		}
+		match kind {
 			.alias {
 				ptr_typ := g.equality_fn(left.typ)
 				if node.op == .ne {
@@ -289,7 +294,9 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 				g.expr(node.right)
 				g.write(')')
 			}
-			else {}
+			else {
+				g.gen_plain_infix_expr(node)
+			}
 		}
 	} else if left.unaliased.idx() in [ast.u32_type_idx, ast.u64_type_idx]
 		&& right.unaliased.is_signed() {

vlib/v/tests/alias_compare_non_alias_test.v

@@ -0,0 +1,21 @@
+struct Foo {
+	name string
+}
+
+type Foo1 = [2][2]int
+type Foo2 = []int
+type Foo3 = Foo
+
+fn test_alias_compare_non_alias_value() {
+	f1 := Foo1([[1, 2]!, [3, 4]!]!)
+	assert f1 == [[1, 2]!, [3, 4]!]!
+	assert [[1, 2]!, [3, 4]!]! == f1
+
+	f2 := Foo2([1, 2, 3, 4])
+	assert f2 == [1, 2, 3, 4]
+	assert [1, 2, 3, 4] == f2
+
+	f3 := Foo3(Foo{'hello'})
+	assert f3 == Foo{'hello'}
+	assert Foo{'hello'} == f3
+}