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checker: stricter type casting error messages

pull/13363/head
Delyan Angelov 2022-02-03 12:24:29 +02:00
parent ede9f29323
commit 85d36ed231
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GPG Key ID: 66886C0F12D595ED
2 changed files with 26 additions and 18 deletions
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38
vlib/v/checker/checker.v
View File

@ -2665,13 +2665,16 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
from_type = node.expr_type
}
if !c.table.sumtype_has_variant(to_type, from_type, false) && !to_type.has_flag(.optional) {
c.error('cannot cast `$from_sym.name` to `$to_sym.name`', node.pos)
ft := c.table.type_to_str(from_type)
tt := c.table.type_to_str(to_type)
c.error('cannot cast `$ft` to `$tt`', node.pos)
}
} else if mut to_sym.info is ast.Alias && !(final_to_sym.kind == .struct_ && to_type.is_ptr()) {
if !c.check_types(from_type, to_sym.info.parent_type) && !(final_to_sym.is_int()
&& final_from_sym.kind in [.enum_, .bool, .i8, .char]) {
c.error('cannot convert type `$from_sym.name` to `$to_sym.name` (alias to `$final_to_sym.name`)',
node.pos)
ft := c.table.type_to_str(from_type)
tt := c.table.type_to_str(to_type)
c.error('cannot cast `$ft` to `$tt` (alias to `$final_to_sym.name`)', node.pos)
}
} else if to_sym.kind == .struct_ && !to_type.is_ptr()
&& !(to_sym.info as ast.Struct).is_typedef {
@ -2686,8 +2689,8 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
node.pos)
}
} else {
type_name := c.table.type_to_str(from_type)
c.error('cannot cast `$type_name` to struct', node.pos)
ft := c.table.type_to_str(from_type)
c.error('cannot cast `$ft` to struct', node.pos)
}
} else if to_sym.kind == .interface_ {
if c.type_implements(from_type, to_type, node.pos) {
@ -2718,8 +2721,9 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
}
} else if to_sym.kind == .byte && !final_from_sym.is_number() && !final_from_sym.is_pointer()
&& !from_type.is_ptr() && final_from_sym.kind !in [.char, .enum_, .bool] {
type_name := c.table.type_to_str(from_type)
c.error('cannot cast type `$type_name` to `byte`', node.pos)
ft := c.table.type_to_str(from_type)
tt := c.table.type_to_str(to_type)
c.error('cannot cast type `$ft` to `$tt`', node.pos)
} else if from_type.has_flag(.optional) || from_type.has_flag(.variadic) {
// variadic case can happen when arrays are converted into variadic
msg := if from_type.has_flag(.optional) { 'an optional' } else { 'a variadic' }
@ -2734,31 +2738,34 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
} else if final_from_sym.kind == .string && final_to_sym.is_number()
&& final_to_sym.kind != .rune {
snexpr := node.expr.str()
c.error('cannot cast string to `$to_sym.name`, use `${snexpr}.${final_to_sym.name}()` instead.',
tt := c.table.type_to_str(to_type)
c.error('cannot cast string to `$tt`, use `${snexpr}.${final_to_sym.name}()` instead.',
node.pos)
}
if to_sym.kind == .rune && from_sym.is_string() {
snexpr := node.expr.str()
c.error('cannot cast `$from_sym.name` to rune, use `${snexpr}.runes()` instead.',
node.pos)
ft := c.table.type_to_str(from_type)
c.error('cannot cast `$ft` to rune, use `${snexpr}.runes()` instead.', node.pos)
}
if to_type == ast.string_type {
if from_type in [ast.byte_type, ast.bool_type] {
snexpr := node.expr.str()
c.error('cannot cast type `$from_sym.name` to string, use `${snexpr}.str()` instead.',
ft := c.table.type_to_str(from_type)
c.error('cannot cast type `$ft` to string, use `${snexpr}.str()` instead.',
node.pos)
} else if from_type.is_real_pointer() {
snexpr := node.expr.str()
c.error('cannot cast pointer type `$from_sym.name` to string, use `&byte($snexpr).vstring()` or `cstring_to_vstring($snexpr)` instead.',
ft := c.table.type_to_str(from_type)
c.error('cannot cast pointer type `$ft` to string, use `&byte($snexpr).vstring()` or `cstring_to_vstring($snexpr)` instead.',
node.pos)
} else if from_type.is_number() {
snexpr := node.expr.str()
c.error('cannot cast number to string, use `${snexpr}.str()` instead.', node.pos)
} else if from_sym.kind == .alias && final_from_sym.name != 'string' {
c.error('cannot cast type `$from_sym.name` to string, use `x.str()` instead.',
node.pos)
ft := c.table.type_to_str(from_type)
c.error('cannot cast type `$ft` to string, use `x.str()` instead.', node.pos)
} else if final_from_sym.kind == .array {
snexpr := node.expr.str()
if final_from_sym.name == '[]byte' {
@ -2776,7 +2783,8 @@ pub fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
c.error('cannot cast map to string.', node.pos)
} else if final_from_sym.kind == .sum_type {
snexpr := node.expr.str()
c.error('cannot cast sumtype `$from_sym.name` to string, use `${snexpr}.str()` instead.',
ft := c.table.type_to_str(from_type)
c.error('cannot cast sumtype `$ft` to string, use `${snexpr}.str()` instead.',
node.pos)
} else if to_type != ast.string_type && from_type == ast.string_type
&& (!(to_sym.kind == .alias && final_to_sym.name == 'string')) {

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

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