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checker: add alias cast type check (closes #6705) (#6709)

pull/6713/head
Daniel Däschle 2020-11-02 01:17:35 +01:00 committed by GitHub
parent 3c0f4c46fa
commit d5a421e3f5
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GPG Key ID: 4AEE18F83AFDEB23
18 changed files with 167 additions and 143 deletions
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6
vlib/time/stopwatch.v
View File

@ -57,11 +57,11 @@ pub fn (mut t StopWatch) pause() {
pub fn (t StopWatch) elapsed() Duration {
if t.start > 0 {
if t.end == 0 {
return Duration(time.sys_mono_now() - t.start + t.elapsed)
return Duration(i64(time.sys_mono_now() - t.start + t.elapsed))
} else {
return Duration(t.end - t.start + t.elapsed)
return Duration(i64(t.end - t.start + t.elapsed))
}
}
return Duration(t.elapsed)
return Duration(i64(t.elapsed))
}

151
vlib/v/checker/checker.v
View File

@ -2683,77 +2683,7 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
return table.bool_type
}
ast.CastExpr {
node.expr_type = c.expr(node.expr)
from_type_sym := c.table.get_type_symbol(node.expr_type)
to_type_sym := c.table.get_type_symbol(node.typ)
expr_is_ptr := node.expr_type.is_ptr() || node.expr_type.idx() in table.pointer_type_idxs
if expr_is_ptr && to_type_sym.kind == .string && !node.in_prexpr {
if node.has_arg {
c.warn('to convert a C string buffer pointer to a V string, please use x.vstring_with_len(len) instead of string(x,len)',
node.pos)
} else {
c.warn('to convert a C string buffer pointer to a V string, please use x.vstring() instead of string(x)',
node.pos)
}
}
if node.expr_type == table.byte_type && to_type_sym.kind == .string {
c.error('can not cast type `byte` to string, use `${node.expr.str()}.str()` instead.',
node.pos)
}
if to_type_sym.kind == .sum_type {
if node.expr_type in [table.any_int_type, table.any_flt_type] {
node.expr_type = c.promote_num(node.expr_type, if node.expr_type == table.any_int_type { table.int_type } else { table.f64_type })
}
if !c.table.sumtype_has_variant(node.typ, node.expr_type) {
c.error('cannot cast `$from_type_sym.source_name` to `$to_type_sym.source_name`',
node.pos)
}
} else if node.typ == table.string_type &&
(from_type_sym.kind in [.any_int, .int, .byte, .byteptr] ||
(from_type_sym.kind == .array && from_type_sym.name == 'array_byte')) {
type_name := c.table.type_to_str(node.expr_type)
c.error('cannot cast type `$type_name` to string, use `x.str()` instead',
node.pos)
} else if node.expr_type == table.string_type {
if to_type_sym.kind != .alias {
mut error_msg := 'cannot cast a string'
if node.expr is ast.StringLiteral {
str_lit := node.expr as ast.StringLiteral
if str_lit.val.len == 1 {
error_msg += ", for denoting characters use `$str_lit.val` instead of '$str_lit.val'"
}
}
c.error(error_msg, node.pos)
}
} else if to_type_sym.kind == .byte &&
node.expr_type != table.voidptr_type && from_type_sym.kind != .enum_ && !node.expr_type.is_int() &&
!node.expr_type.is_float() && !node.expr_type.is_ptr() {
type_name := c.table.type_to_str(node.expr_type)
c.error('cannot cast type `$type_name` to `byte`', node.pos)
} else if to_type_sym.kind == .struct_ && !node.typ.is_ptr() && !(to_type_sym.info as table.Struct).is_typedef {
// For now we ignore C typedef because of `C.Window(C.None)` in vlib/clipboard
if from_type_sym.kind == .struct_ && !node.expr_type.is_ptr() {
from_type_info := from_type_sym.info as table.Struct
to_type_info := to_type_sym.info as table.Struct
if !c.check_struct_signature(from_type_info, to_type_info) {
c.error('cannot convert struct `$from_type_sym.source_name` to struct `$to_type_sym.source_name`',
node.pos)
}
} else {
type_name := c.table.type_to_str(node.expr_type)
c.error('cannot cast `$type_name` to struct', node.pos)
}
} else if node.typ == table.bool_type {
c.error('cannot cast to bool - use e.g. `some_int != 0` instead', node.pos)
} else if node.expr_type == table.none_type {
type_name := c.table.type_to_str(node.typ)
c.error('cannot cast `none` to `$type_name`', node.pos)
}
if node.has_arg {
c.expr(node.arg)
}
node.typname = c.table.get_type_symbol(node.typ).name
return node.typ
return c.cast_expr(mut node)
}
ast.CallExpr {
return c.call_expr(mut node)
@ -2959,6 +2889,85 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
return table.void_type
}
pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) table.Type {
node.expr_type = c.expr(node.expr)
from_type_sym := c.table.get_type_symbol(node.expr_type)
to_type_sym := c.table.get_type_symbol(node.typ)
expr_is_ptr := node.expr_type.is_ptr() || node.expr_type.idx() in table.pointer_type_idxs
if expr_is_ptr && to_type_sym.kind == .string && !node.in_prexpr {
if node.has_arg {
c.warn('to convert a C string buffer pointer to a V string, please use x.vstring_with_len(len) instead of string(x,len)',
node.pos)
} else {
c.warn('to convert a C string buffer pointer to a V string, please use x.vstring() instead of string(x)',
node.pos)
}
}
if node.expr_type == table.byte_type && to_type_sym.kind == .string {
c.error('can not cast type `byte` to string, use `${node.expr.str()}.str()` instead.',
node.pos)
}
if to_type_sym.kind == .sum_type {
if node.expr_type in [table.any_int_type, table.any_flt_type] {
node.expr_type = c.promote_num(node.expr_type, if node.expr_type == table.any_int_type { table.int_type } else { table.f64_type })
}
if !c.table.sumtype_has_variant(node.typ, node.expr_type) {
c.error('cannot cast `$from_type_sym.source_name` to `$to_type_sym.source_name`',
node.pos)
}
} else if to_type_sym.info is table.Alias as alias_info {
if !c.check_types(node.expr_type, alias_info.parent_type) {
parent_type_sym := c.table.get_type_symbol(alias_info.parent_type)
c.error('cannot convert type `$from_type_sym.source_name` to `$to_type_sym.source_name` (alias to `$parent_type_sym.source_name`)',
node.pos)
}
} else if node.typ == table.string_type &&
(from_type_sym.kind in [.any_int, .int, .byte, .byteptr] ||
(from_type_sym.kind == .array && from_type_sym.name == 'array_byte')) {
type_name := c.table.type_to_str(node.expr_type)
c.error('cannot cast type `$type_name` to string, use `x.str()` instead', node.pos)
} else if node.expr_type == table.string_type {
if to_type_sym.kind != .alias {
mut error_msg := 'cannot cast a string'
if node.expr is ast.StringLiteral {
str_lit := node.expr as ast.StringLiteral
if str_lit.val.len == 1 {
error_msg += ", for denoting characters use `$str_lit.val` instead of '$str_lit.val'"
}
}
c.error(error_msg, node.pos)
}
} else if to_type_sym.kind == .byte &&
node.expr_type != table.voidptr_type && from_type_sym.kind != .enum_ && !node.expr_type.is_int() &&
!node.expr_type.is_float() && !node.expr_type.is_ptr() {
type_name := c.table.type_to_str(node.expr_type)
c.error('cannot cast type `$type_name` to `byte`', node.pos)
} else if to_type_sym.kind == .struct_ && !node.typ.is_ptr() && !(to_type_sym.info as table.Struct).is_typedef {
// For now we ignore C typedef because of `C.Window(C.None)` in vlib/clipboard
if from_type_sym.kind == .struct_ && !node.expr_type.is_ptr() {
from_type_info := from_type_sym.info as table.Struct
to_type_info := to_type_sym.info as table.Struct
if !c.check_struct_signature(from_type_info, to_type_info) {
c.error('cannot convert struct `$from_type_sym.source_name` to struct `$to_type_sym.source_name`',
node.pos)
}
} else {
type_name := c.table.type_to_str(node.expr_type)
c.error('cannot cast `$type_name` to struct', node.pos)
}
} else if node.typ == table.bool_type {
c.error('cannot cast to bool - use e.g. `some_int != 0` instead', node.pos)
} else if node.expr_type == table.none_type {
type_name := c.table.type_to_str(node.typ)
c.error('cannot cast `none` to `$type_name`', node.pos)
}
if node.has_arg {
c.expr(node.arg)
}
node.typname = c.table.get_type_symbol(node.typ).name
return node.typ
}
pub fn (mut c Checker) ident(mut ident ast.Ident) table.Type {
// TODO: move this
if c.const_deps.len > 0 {

6
vlib/v/checker/tests/cannot_cast_to_alias.out 100644
View File

@ -0,0 +1,6 @@
vlib/v/checker/tests/cannot_cast_to_alias.vv:6:7: error: cannot convert type `any_int` to `MyType` (alias to `string`)
4 |
5 | fn main() {
6 | _ := MyType(5)
| ~~~~~~~~~
7 | }

7
vlib/v/checker/tests/cannot_cast_to_alias.vv 100644
View File

@ -0,0 +1,7 @@
module main
type MyType = string
fn main() {
_ := MyType(5)
}

18
vlib/v/checker/tests/cannot_cast_to_struct.out
View File

@ -1,27 +1,27 @@
vlib/v/checker/tests/cannot_cast_to_struct.vv:10:12: error: cannot convert struct `Abc` to struct `Test`
vlib/v/checker/tests/cannot_cast_to_struct.vv:10:7: error: cannot convert struct `Abc` to struct `Test`
8 |
9 | fn main() {
10 | _ := Test(Abc{})
| ~~~~~
| ~~~~~~~~~~~
11 | sum := Alphabet(Xyz{})
12 | _ = Xyz(sum)
vlib/v/checker/tests/cannot_cast_to_struct.vv:12:10: error: cannot cast `Alphabet` to struct
vlib/v/checker/tests/cannot_cast_to_struct.vv:12:6: error: cannot cast `Alphabet` to struct
10 | _ := Test(Abc{})
11 | sum := Alphabet(Xyz{})
12 | _ = Xyz(sum)
| ~~~
| ~~~~~~~~
13 | _ = Xyz(5)
14 | s := Abc{}
vlib/v/checker/tests/cannot_cast_to_struct.vv:13:10: error: cannot cast `any_int` to struct
vlib/v/checker/tests/cannot_cast_to_struct.vv:13:6: error: cannot cast `any_int` to struct
11 | sum := Alphabet(Xyz{})
12 | _ = Xyz(sum)
13 | _ = Xyz(5)
| ^
| ~~~~~~
14 | s := Abc{}
15 | _ = Xyz(&s)
vlib/v/checker/tests/cannot_cast_to_struct.vv:15:10: error: cannot cast `&Abc` to struct
vlib/v/checker/tests/cannot_cast_to_struct.vv:15:6: error: cannot cast `&Abc` to struct
13 | _ = Xyz(5)
14 | s := Abc{}
15 | _ = Xyz(&s)
| ^
16 | }
| ~~~~~~~
16 | }

14
vlib/v/checker/tests/cast_err.out
View File

@ -1,20 +1,20 @@
vlib/v/checker/tests/cast_err.vv:3:11: error: cannot cast to bool - use e.g. `some_int != 0` instead
vlib/v/checker/tests/cast_err.vv:3:6: error: cannot cast to bool - use e.g. `some_int != 0` instead
1 | fn test_bool_cast() {
2 | v := 3
3 | _ = bool(v)
| ^
| ~~~~~~~
4 | _ = bool(&v)
5 | _ = bool([2])
vlib/v/checker/tests/cast_err.vv:4:11: error: cannot cast to bool - use e.g. `some_int != 0` instead
vlib/v/checker/tests/cast_err.vv:4:6: error: cannot cast to bool - use e.g. `some_int != 0` instead
2 | v := 3
3 | _ = bool(v)
4 | _ = bool(&v)
| ^
| ~~~~~~~~
5 | _ = bool([2])
6 | }
vlib/v/checker/tests/cast_err.vv:5:11: error: cannot cast to bool - use e.g. `some_int != 0` instead
vlib/v/checker/tests/cast_err.vv:5:6: error: cannot cast to bool - use e.g. `some_int != 0` instead
3 | _ = bool(v)
4 | _ = bool(&v)
5 | _ = bool([2])
| ~~~
6 | }
| ~~~~~~~~~
6 | }

6
vlib/v/checker/tests/cast_string_err.out
View File

@ -1,6 +1,6 @@
vlib/v/checker/tests/cast_string_err.vv:2:14: error: cannot cast type `any_int` to string, use `x.str()` instead
vlib/v/checker/tests/cast_string_err.vv:2:7: error: cannot cast type `any_int` to string, use `x.str()` instead
1 | fn main() {
2 | a := string(1)
| ^
| ~~~~~~~~~
3 | println(a)
4 | }
4 | }

6
vlib/v/checker/tests/cast_string_with_byte_err.out
View File

@ -1,5 +1,5 @@
vlib/v/checker/tests/cast_string_with_byte_err.vv:2:19: error: can not cast type `byte` to string, use `by.str()` instead.
vlib/v/checker/tests/cast_string_with_byte_err.vv:2:12: error: can not cast type `byte` to string, use `by.str()` instead.
1 | for by in 'abc' {
2 | println(string(by))
| ~~
3 | }
| ~~~~~~~~~~
3 | }

8
vlib/v/checker/tests/float_modulo_err.out
View File

@ -1,12 +1,12 @@
vlib/v/checker/tests/float_modulo_err.vv:2:13: error: float modulo not allowed, use math.fmod() instead
vlib/v/checker/tests/float_modulo_err.vv:2:13: error: float modulo not allowed, use math.fmod() instead
1 | fn main() {
2 | println(3.0 % 2.0)
| ~~~
3 | println(f32(3.0) % f32(2.0))
4 | }
vlib/v/checker/tests/float_modulo_err.vv:3:17: error: float modulo not allowed, use math.fmod() instead
vlib/v/checker/tests/float_modulo_err.vv:3:13: error: float modulo not allowed, use math.fmod() instead
1 | fn main() {
2 | println(3.0 % 2.0)
3 | println(f32(3.0) % f32(2.0))
| ~~~
4 | }
| ~~~~~~~~
4 | }

46
vlib/v/checker/tests/none_type_cast_err.out
View File

@ -1,75 +1,75 @@
vlib/v/checker/tests/none_type_cast_err.vv:2:14: error: cannot cast `none` to `string`
vlib/v/checker/tests/none_type_cast_err.vv:2:7: error: cannot cast `none` to `string`
1 | fn main() {
2 | _ := string(none)
| ~~~~
| ~~~~~~~~~~~~
3 | _ := int(none)
4 | _ := i8(none)
vlib/v/checker/tests/none_type_cast_err.vv:3:11: error: cannot cast `none` to `int`
vlib/v/checker/tests/none_type_cast_err.vv:3:7: error: cannot cast `none` to `int`
1 | fn main() {
2 | _ := string(none)
3 | _ := int(none)
| ~~~~
| ~~~~~~~~~
4 | _ := i8(none)
5 | _ := i16(none)
vlib/v/checker/tests/none_type_cast_err.vv:4:10: error: cannot cast `none` to `i8`
vlib/v/checker/tests/none_type_cast_err.vv:4:7: error: cannot cast `none` to `i8`
2 | _ := string(none)
3 | _ := int(none)
4 | _ := i8(none)
| ~~~~
| ~~~~~~~~
5 | _ := i16(none)
6 | _ := i64(none)
vlib/v/checker/tests/none_type_cast_err.vv:5:11: error: cannot cast `none` to `i16`
vlib/v/checker/tests/none_type_cast_err.vv:5:7: error: cannot cast `none` to `i16`
3 | _ := int(none)
4 | _ := i8(none)
5 | _ := i16(none)
| ~~~~
| ~~~~~~~~~
6 | _ := i64(none)
7 | _ := u16(none)
vlib/v/checker/tests/none_type_cast_err.vv:6:11: error: cannot cast `none` to `i64`
vlib/v/checker/tests/none_type_cast_err.vv:6:7: error: cannot cast `none` to `i64`
4 | _ := i8(none)
5 | _ := i16(none)
6 | _ := i64(none)
| ~~~~
| ~~~~~~~~~
7 | _ := u16(none)
8 | _ := u32(none)
vlib/v/checker/tests/none_type_cast_err.vv:7:11: error: cannot cast `none` to `u16`
vlib/v/checker/tests/none_type_cast_err.vv:7:7: error: cannot cast `none` to `u16`
5 | _ := i16(none)
6 | _ := i64(none)
7 | _ := u16(none)
| ~~~~
| ~~~~~~~~~
8 | _ := u32(none)
9 | _ := u64(none)
vlib/v/checker/tests/none_type_cast_err.vv:8:11: error: cannot cast `none` to `u32`
vlib/v/checker/tests/none_type_cast_err.vv:8:7: error: cannot cast `none` to `u32`
6 | _ := i64(none)
7 | _ := u16(none)
8 | _ := u32(none)
| ~~~~
| ~~~~~~~~~
9 | _ := u64(none)
10 | _ := rune(none)
vlib/v/checker/tests/none_type_cast_err.vv:9:11: error: cannot cast `none` to `u64`
vlib/v/checker/tests/none_type_cast_err.vv:9:7: error: cannot cast `none` to `u64`
7 | _ := u16(none)
8 | _ := u32(none)
9 | _ := u64(none)
| ~~~~
| ~~~~~~~~~
10 | _ := rune(none)
11 | _ := f32(none)
vlib/v/checker/tests/none_type_cast_err.vv:10:12: error: cannot cast `none` to `rune`
vlib/v/checker/tests/none_type_cast_err.vv:10:7: error: cannot cast `none` to `rune`
8 | _ := u32(none)
9 | _ := u64(none)
10 | _ := rune(none)
| ~~~~
| ~~~~~~~~~~
11 | _ := f32(none)
12 | _ := f64(none)
vlib/v/checker/tests/none_type_cast_err.vv:11:11: error: cannot cast `none` to `f32`
vlib/v/checker/tests/none_type_cast_err.vv:11:7: error: cannot cast `none` to `f32`
9 | _ := u64(none)
10 | _ := rune(none)
11 | _ := f32(none)
| ~~~~
| ~~~~~~~~~
12 | _ := f64(none)
13 | }
vlib/v/checker/tests/none_type_cast_err.vv:12:11: error: cannot cast `none` to `f64`
vlib/v/checker/tests/none_type_cast_err.vv:12:7: error: cannot cast `none` to `f64`
10 | _ := rune(none)
11 | _ := f32(none)
12 | _ := f64(none)
| ~~~~
13 | }
| ~~~~~~~~~
13 | }

4
vlib/v/checker/tests/struct_cast_to_struct_generic_err.out
View File

@ -1,6 +1,6 @@
vlib/v/checker/tests/struct_cast_to_struct_generic_err.vv:11:11: error: cannot convert struct `Abc<int>` to struct `Xyz`
vlib/v/checker/tests/struct_cast_to_struct_generic_err.vv:11:7: error: cannot convert struct `Abc<int>` to struct `Xyz`
9 | fn main() {
10 | abc := Abc<int>{}
11 | _ := Xyz(abc)
| ~~~
| ~~~~~~~~
12 | }

4
vlib/v/checker/tests/struct_cast_to_struct_mut_err_a.out
View File

@ -1,6 +1,6 @@
vlib/v/checker/tests/struct_cast_to_struct_mut_err_a.vv:12:11: error: cannot convert struct `Abc` to struct `Xyz`
vlib/v/checker/tests/struct_cast_to_struct_mut_err_a.vv:12:7: error: cannot convert struct `Abc` to struct `Xyz`
10 | fn main() {
11 | abc := Abc{}
12 | _ := Xyz(abc)
| ~~~
| ~~~~~~~~
13 | }

4
vlib/v/checker/tests/struct_cast_to_struct_mut_err_b.out
View File

@ -1,6 +1,6 @@
vlib/v/checker/tests/struct_cast_to_struct_mut_err_b.vv:12:11: error: cannot convert struct `Abc` to struct `Xyz`
vlib/v/checker/tests/struct_cast_to_struct_mut_err_b.vv:12:7: error: cannot convert struct `Abc` to struct `Xyz`
10 | fn main() {
11 | abc := Abc{}
12 | _ := Xyz(abc)
| ~~~
| ~~~~~~~~
13 | }

4
vlib/v/checker/tests/struct_cast_to_struct_pub_err_a.out
View File

@ -1,6 +1,6 @@
vlib/v/checker/tests/struct_cast_to_struct_pub_err_a.vv:12:11: error: cannot convert struct `Abc` to struct `Xyz`
vlib/v/checker/tests/struct_cast_to_struct_pub_err_a.vv:12:7: error: cannot convert struct `Abc` to struct `Xyz`
10 | fn main() {
11 | abc := Abc{}
12 | _ := Xyz(abc)
| ~~~
| ~~~~~~~~
13 | }

4
vlib/v/checker/tests/struct_cast_to_struct_pub_err_b.out
View File

@ -1,6 +1,6 @@
vlib/v/checker/tests/struct_cast_to_struct_pub_err_b.vv:12:11: error: cannot convert struct `Abc` to struct `Xyz`
vlib/v/checker/tests/struct_cast_to_struct_pub_err_b.vv:12:7: error: cannot convert struct `Abc` to struct `Xyz`
10 | fn main() {
11 | abc := Abc{}
12 | _ := Xyz(abc)
| ~~~
| ~~~~~~~~
13 | }

8
vlib/v/checker/tests/sum.out
View File

@ -12,11 +12,11 @@ vlib/v/checker/tests/sum.vv:6:8: error: cannot cast non-sum type `int` using `as
| ~~
7 | }
8 |
vlib/v/checker/tests/sum.vv:10:11: error: cannot cast `rune` to `Var`
8 |
vlib/v/checker/tests/sum.vv:10:7: error: cannot cast `rune` to `Var`
8 |
9 | fn sum() {
10 | _ := Var(`J`)
| ~~~
| ~~~~~~~~
11 | mut s2 := Var('')
12 | s2 = true
vlib/v/checker/tests/sum.vv:12:7: error: cannot assign to `s2`: expected `Var`, not `bool`
@ -24,4 +24,4 @@ vlib/v/checker/tests/sum.vv:12:7: error: cannot assign to `s2`: expected `Var`,
11 | mut s2 := Var('')
12 | s2 = true
| ~~~~
13 | }
13 | }

10
vlib/v/checker/tests/warnings_for_string_c2v_calls.out
View File

@ -1,14 +1,14 @@
vlib/v/checker/tests/warnings_for_string_c2v_calls.vv:8:14: error: to convert a C string buffer pointer to a V string, please use x.vstring() instead of string(x)
vlib/v/checker/tests/warnings_for_string_c2v_calls.vv:8:7: error: to convert a C string buffer pointer to a V string, please use x.vstring() instead of string(x)
6 | p[2] = `z`
7 | }
8 | x := string(p)
| ^
| ~~~~~~~~~
9 | y := string(p, 10)
10 | eprintln('x: $x | y: $y')
vlib/v/checker/tests/warnings_for_string_c2v_calls.vv:9:14: error: to convert a C string buffer pointer to a V string, please use x.vstring_with_len(len) instead of string(x,len)
vlib/v/checker/tests/warnings_for_string_c2v_calls.vv:9:7: error: to convert a C string buffer pointer to a V string, please use x.vstring_with_len(len) instead of string(x,len)
7 | }
8 | x := string(p)
9 | y := string(p, 10)
| ^
| ~~~~~~~~~~~~~
10 | eprintln('x: $x | y: $y')
11 | eprintln('x.len: $x.len | y.len: $y.len')
11 | eprintln('x.len: $x.len | y.len: $y.len')

4
vlib/v/parser/parser.v
View File

@ -1059,6 +1059,7 @@ pub fn (mut p Parser) name_expr() ast.Expr {
is_mod_cast || (!(name.len > 1 && name[0] == `C` && name[1] == `.`) && name[0].is_capital()) {
// MainLetter(x) is *always* a cast, as long as it is not `C.`
// TODO handle C.stat()
start_pos := p.tok.position()
mut to_typ := p.parse_type()
if p.is_amp {
// Handle `&Foo(0)`
@ -1079,13 +1080,14 @@ pub fn (mut p Parser) name_expr() ast.Expr {
arg = p.expr(0) // len
has_arg = true
}
end_pos := p.tok.position()
p.check(.rpar)
node = ast.CastExpr{
typ: to_typ
expr: expr
arg: arg
has_arg: has_arg
pos: expr.position()
pos: start_pos.extend(end_pos)
}
p.expr_mod = ''
return node