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Only suggest casting numeric types using into()

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This commit is contained in:
Esteban Küber 2018-01-07 12:51:33 -08:00
parent af91d9955b
commit 509ea8efc6
6 changed files with 494 additions and 989 deletions
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34
src/librustc_typeck/check/demand.rs
View file

@ -331,13 +331,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// We want to minimize the amount of casting operations that are suggested, as it can be a
// lossy operation with potentially bad side effects, so we only suggest when encountering
// an expression that indicates that the original type couldn't be directly changed.
let can_cast = match expr.node {
hir::ExprPath(..) |
hir::ExprCall(..) |
hir::ExprMethodCall(..) |
hir::ExprBinary(..) => true,
_ => false,
};
//
// For now, don't suggest casting with `as`.
let can_cast = false;
let needs_paren = match expr.node {
hir::ExprBinary(..) => true,
@ -369,7 +365,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
(None, _) | (_, None) => {
if can_cast {
err.span_suggestion(expr.span,
&format!("{}, which {}", msg, depending_on_isize),
&format!("{}, which {}",
msg,
depending_on_isize),
cast_suggestion);
}
}
@ -393,7 +391,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
(None, _) | (_, None) => {
if can_cast {
err.span_suggestion(expr.span,
&format!("{}, which {}", msg, depending_on_usize),
&format!("{}, which {}",
msg,
depending_on_usize),
cast_suggestion);
}
}
@ -420,12 +420,16 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
(None, _) => {
err.span_suggestion(expr.span,
&format!("{}, which {}", msg, depending_on_isize),
&format!("{}, which {}",
msg,
depending_on_isize),
cast_suggestion);
}
(_, None) => {
err.span_suggestion(expr.span,
&format!("{}, which {}", msg, depending_on_usize),
&format!("{}, which {}",
msg,
depending_on_usize),
cast_suggestion);
}
_ => {
@ -452,12 +456,16 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
(None, _) => {
err.span_suggestion(expr.span,
&format!("{}, which {}", msg, depending_on_usize),
&format!("{}, which {}",
msg,
depending_on_usize),
cast_suggestion);
}
(_, None) => {
err.span_suggestion(expr.span,
&format!("{}, which {}", msg, depending_on_isize),
&format!("{}, which {}",
msg,
depending_on_isize),
cast_suggestion);
}
_ => {

4
src/test/ui/mismatched_types/issue-26480.stderr
View file

@ -6,10 +6,6 @@ error[E0308]: mismatched types
...
37 | write!(hello);
| -------------- in this macro invocation
help: you can cast an `usize` to `u64`, which will truncate or zero-extend depending on the bit width of `usize`
|
26 | ($arr.len() * size_of($arr[0])) as u64); //~ ERROR mismatched types
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0605]: non-primitive cast: `{integer}` as `()`
--> $DIR/issue-26480.rs:32:19

4
src/test/ui/suggestions/numeric-cast-2.rs
View file

@ -12,7 +12,9 @@ fn foo() -> i32 {
4
}
fn main() {
let x: u32 = foo();
let x: u16 = foo();
//~^ ERROR mismatched types
let y: i64 = x + x;
//~^ ERROR mismatched types
let z: i32 = x + x;
//~^ ERROR mismatched types

22
src/test/ui/suggestions/numeric-cast-2.stderr
View file

@ -1,22 +1,20 @@
error[E0308]: mismatched types
--> $DIR/numeric-cast-2.rs:15:18
|
15 | let x: u32 = foo();
| ^^^^^ expected u32, found i32
help: you can cast an `i32` to `u32`, which will sign-extend the source value
|
15 | let x: u32 = foo() as u32;
| ^^^^^^^^^^^^
15 | let x: u16 = foo();
| ^^^^^ expected u16, found i32
error[E0308]: mismatched types
--> $DIR/numeric-cast-2.rs:17:18
|
17 | let z: i32 = x + x;
| ^^^^^ expected i32, found u32
help: you can cast an `u32` to `i32`, which will truncate the source value
17 | let y: i64 = x + x;
| ^^^^^ expected i64, found u16
error[E0308]: mismatched types
--> $DIR/numeric-cast-2.rs:19:18
|
17 | let z: i32 = (x + x) as i32;
| ^^^^^^^^^^^^^^
19 | let z: i32 = x + x;
| ^^^^^ expected i32, found u16
error: aborting due to 2 previous errors
error: aborting due to 3 previous errors

21
src/test/ui/suggestions/numeric-cast.rs
View file

@ -46,10 +46,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<usize>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<usize>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<isize>(x_usize);
//~^ ERROR mismatched types
@ -72,10 +70,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<isize>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<isize>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u64>(x_usize);
//~^ ERROR mismatched types
@ -98,10 +94,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<u64>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u64>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i64>(x_usize);
//~^ ERROR mismatched types
@ -124,10 +118,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<i64>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i64>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u32>(x_usize);
//~^ ERROR mismatched types
@ -150,10 +142,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<u32>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u32>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i32>(x_usize);
//~^ ERROR mismatched types
@ -176,10 +166,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<i32>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i32>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u16>(x_usize);
//~^ ERROR mismatched types
@ -202,10 +190,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<u16>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u16>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i16>(x_usize);
//~^ ERROR mismatched types
@ -228,10 +214,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<i16>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i16>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u8>(x_usize);
//~^ ERROR mismatched types
@ -254,10 +238,8 @@ fn main() {
//~^ ERROR mismatched types
foo::<u8>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<u8>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i8>(x_usize);
//~^ ERROR mismatched types
@ -280,10 +262,8 @@ fn main() {
foo::<i8>(x_i8);
foo::<i8>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<i8>(x_f32);
//~^ ERROR mismatched types
//~| WARN casting here will cause Undefined Behavior
foo::<f64>(x_usize);
//~^ ERROR mismatched types
@ -331,6 +311,5 @@ fn main() {
//~^ ERROR mismatched types
foo::<f32>(x_f64);
//~^ ERROR mismatched types
//~| WARN casting here will cause undefined behavior
foo::<f32>(x_f32);
}

1398
src/test/ui/suggestions/numeric-cast.stderr
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