6b24fdf811
```
error: unconstrained generic constant
--> $DIR/const-argument-if-length.rs:18:10
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LL | pad: [u8; is_zst::<T>()],
| ^^^^^^^^^^^^^^^^^^^
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help: try adding a `where` bound
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LL | pub struct AtLeastByte<T: ?Sized> where [(); is_zst::<T>()]: {
| ++++++++++++++++++++++++++
```
Detect when the constant expression isn't `usize` and suggest casting:
```
error: unconstrained generic constant
--> f300.rs:6:10
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6 | bb::<{!N}>();
| ^^^^
-Ztrack-diagnostics: created at compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs:3539:36
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help: try adding a `where` bound
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5 | fn b<const N: bool>() where [(); {!N} as usize]: {
| ++++++++++++++++++++++++++
```
Fix #122395.
65 lines
1.5 KiB
Plaintext
65 lines
1.5 KiB
Plaintext
error: unconstrained generic constant
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--> $DIR/issue-71202.rs:11:5
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LL | / const ITEM_IS_COPY: [(); 1 - {
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LL | | trait NotCopy {
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LL | | const VALUE: bool = false;
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LL | | }
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... |
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LL | | <IsCopy<T>>::VALUE
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LL | | } as usize] = [];
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| |_____________________^
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help: try adding a `where` bound
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LL ~ } as usize] where [(); 1 - {
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LL + trait NotCopy {
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LL + const VALUE: bool = false;
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LL + }
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LL +
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LL + impl<__Type: ?Sized> NotCopy for __Type {}
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LL +
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LL + struct IsCopy<__Type: ?Sized>(PhantomData<__Type>);
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LL +
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LL + impl<__Type> IsCopy<__Type>
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LL + where
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LL + __Type: Sized + Copy,
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LL + {
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LL + const VALUE: bool = true;
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LL + }
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LL +
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LL + <IsCopy<T>>::VALUE
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LL ~ } as usize]: = [];
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error: unconstrained generic constant
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--> $DIR/issue-71202.rs:28:19
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LL | } as usize] = [];
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| ^^
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help: try adding a `where` bound
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LL ~ } as usize] where [(); 1 - {
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LL + trait NotCopy {
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LL + const VALUE: bool = false;
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LL + }
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LL +
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LL + impl<__Type: ?Sized> NotCopy for __Type {}
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LL +
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LL + struct IsCopy<__Type: ?Sized>(PhantomData<__Type>);
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LL +
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LL + impl<__Type> IsCopy<__Type>
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LL + where
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LL + __Type: Sized + Copy,
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LL + {
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LL + const VALUE: bool = true;
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LL + }
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LL +
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LL + <IsCopy<T>>::VALUE
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LL ~ } as usize]: = [];
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error: aborting due to 2 previous errors
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