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handle mismatched generic parameter kinds

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This commit is contained in:
Ellen 2022-05-05 12:23:42 +01:00
parent fed2c43bbf
commit 6225e980bf
5 changed files with 263 additions and 54 deletions
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213
compiler/rustc_typeck/src/check/compare_method.rs
View File

@ -48,6 +48,10 @@ crate fn compare_impl_method<'tcx>(
return;
}
if let Err(_) = compare_generic_param_kinds(tcx, impl_m, trait_m, trait_item_span) {
return;
}
if let Err(_) =
compare_number_of_method_arguments(tcx, impl_m, impl_m_span, trait_m, trait_item_span)
{
@ -62,10 +66,6 @@ crate fn compare_impl_method<'tcx>(
{
return;
}
if let Err(_) = compare_const_param_types(tcx, impl_m, trait_m, trait_item_span) {
return;
}
}
fn compare_predicate_entailment<'tcx>(
@ -914,62 +914,165 @@ fn compare_synthetic_generics<'tcx>(
if let Some(reported) = error_found { Err(reported) } else { Ok(()) }
}
fn compare_const_param_types<'tcx>(
/// Checks that all parameters in the generics of a given assoc item in a trait impl have
/// the same kind as the respective generic parameter in the trait def.
///
/// For example all 4 errors in the following code are emitted here:
/// ```
/// trait Foo {
/// fn foo<const N: u8>();
/// type bar<const N: u8>;
/// fn baz<const N: u32>();
/// type blah<T>;
/// }
///
/// impl Foo for () {
/// fn foo<const N: u64>() {}
/// //~^ error
/// type bar<const N: u64> {}
/// //~^ error
/// fn baz<T>() {}
/// //~^ error
/// type blah<const N: i64> = u32;
/// //~^ error
/// }
/// ```
///
/// This function does not handle lifetime parameters
fn compare_generic_param_kinds<'tcx>(
tcx: TyCtxt<'tcx>,
impl_m: &ty::AssocItem,
trait_m: &ty::AssocItem,
impl_item: &ty::AssocItem,
trait_item: &ty::AssocItem,
trait_item_span: Option<Span>,
) -> Result<(), ErrorGuaranteed> {
let const_params_of = |def_id| {
tcx.generics_of(def_id).params.iter().filter_map(|param| match param.kind {
GenericParamDefKind::Const { .. } => Some(param.def_id),
_ => None,
assert_eq!(impl_item.kind, trait_item.kind);
let ty_const_params_of = |def_id| {
tcx.generics_of(def_id).params.iter().filter(|param| {
matches!(
param.kind,
GenericParamDefKind::Const { .. } | GenericParamDefKind::Type { .. }
)
})
};
let const_params_impl = const_params_of(impl_m.def_id);
let const_params_trait = const_params_of(trait_m.def_id);
for (const_param_impl, const_param_trait) in iter::zip(const_params_impl, const_params_trait) {
let impl_ty = tcx.type_of(const_param_impl);
let trait_ty = tcx.type_of(const_param_trait);
if impl_ty != trait_ty {
let (impl_span, impl_ident) = match tcx.hir().get_if_local(const_param_impl) {
Some(hir::Node::GenericParam(hir::GenericParam { span, name, .. })) => (
span,
match name {
hir::ParamName::Plain(ident) => Some(ident),
_ => None,
},
),
other => bug!(
"expected GenericParam, found {:?}",
other.map_or_else(|| "nothing".to_string(), |n| format!("{:?}", n))
),
};
let trait_span = match tcx.hir().get_if_local(const_param_trait) {
Some(hir::Node::GenericParam(hir::GenericParam { span, .. })) => Some(span),
_ => None,
};
let mut err = struct_span_err!(
tcx.sess,
*impl_span,
E0053,
"method `{}` has an incompatible const parameter type for trait",
trait_m.name
);
err.span_note(
trait_span.map_or_else(|| trait_item_span.unwrap_or(*impl_span), |span| *span),
&format!(
"the const parameter{} has type `{}`, but the declaration \
in trait `{}` has type `{}`",
&impl_ident.map_or_else(|| "".to_string(), |ident| format!(" `{ident}`")),
impl_ty,
tcx.def_path_str(trait_m.def_id),
trait_ty
),
);
let reported = err.emit();
return Err(reported);
let get_param_span = |param: &ty::GenericParamDef| match tcx.hir().get_if_local(param.def_id) {
Some(hir::Node::GenericParam(hir::GenericParam { span, .. })) => Some(span),
_ => None,
};
let get_param_ident = |param: &ty::GenericParamDef| match tcx.hir().get_if_local(param.def_id) {
Some(hir::Node::GenericParam(hir::GenericParam { name, .. })) => match name {
hir::ParamName::Plain(ident) => Some(ident),
_ => None,
},
other => bug!(
"expected GenericParam, found {:?}",
other.map_or_else(|| "nothing".to_string(), |n| format!("{:?}", n))
),
};
let ty_const_params_impl = ty_const_params_of(impl_item.def_id);
let ty_const_params_trait = ty_const_params_of(trait_item.def_id);
let assoc_item_str = assoc_item_kind_str(&impl_item);
for (param_impl, param_trait) in iter::zip(ty_const_params_impl, ty_const_params_trait) {
use GenericParamDefKind::*;
match (&param_impl.kind, &param_trait.kind) {
(Const { .. }, Const { .. }) => {
let impl_ty = tcx.type_of(param_impl.def_id);
let trait_ty = tcx.type_of(param_trait.def_id);
if impl_ty != trait_ty {
let param_impl_span = get_param_span(param_impl).unwrap();
let param_impl_ident = get_param_ident(param_impl);
let param_trait_span = get_param_span(param_trait);
let mut err = struct_span_err!(
tcx.sess,
*param_impl_span,
E0053,
"{} `{}` has an incompatible const parameter type for trait",
assoc_item_str,
trait_item.name,
);
err.span_note(
param_trait_span.map_or_else(
|| trait_item_span.unwrap_or(*param_impl_span),
|span| *span,
),
&format!(
"the const parameter{} has type `{}`, but the declaration \
in trait `{}` has type `{}`",
&param_impl_ident
.map_or_else(|| "".to_string(), |ident| format!(" `{ident}`")),
impl_ty,
tcx.def_path_str(trait_item.def_id),
trait_ty
),
);
let reported = err.emit();
return Err(reported);
}
}
(Const { .. }, Type { .. }) => {
let impl_ty = tcx.type_of(param_impl.def_id);
let param_impl_span = get_param_span(param_impl).unwrap();
let param_impl_ident = get_param_ident(param_impl);
let param_trait_span = get_param_span(param_trait);
let mut err = struct_span_err!(
tcx.sess,
*param_impl_span,
E0053,
"{} `{}` has an incompatible generic parameter for trait",
assoc_item_str,
trait_item.name,
);
err.span_note(
param_trait_span
.map_or_else(|| trait_item_span.unwrap_or(*param_impl_span), |span| *span),
&format!(
"the trait impl specifies{} a const parameter of type `{}`, but the declaration \
in trait `{}` requires it is a type parameter",
&param_impl_ident
.map_or_else(|| "".to_string(), |ident| format!(" `{ident}` is")),
impl_ty,
tcx.def_path_str(trait_item.def_id),
),
);
let reported = err.emit();
return Err(reported);
}
(Type { .. }, Const { .. }) => {
let trait_ty = tcx.type_of(param_trait.def_id);
let param_impl_span = get_param_span(param_impl).unwrap();
let param_impl_ident = get_param_ident(param_impl);
let param_trait_span = get_param_span(param_trait);
let mut err = struct_span_err!(
tcx.sess,
*param_impl_span,
E0053,
"{} `{}` has an incompatible generic parameter for trait",
assoc_item_str,
trait_item.name,
);
err.span_note(
param_trait_span
.map_or_else(|| trait_item_span.unwrap_or(*param_impl_span), |span| *span),
&format!(
"the trait impl specifies{} a type parameter, but the declaration \
in trait `{}` requires it is a const parameter of type `{}`",
&param_impl_ident
.map_or_else(|| "".to_string(), |ident| format!(" `{ident}` is")),
tcx.def_path_str(trait_item.def_id),
trait_ty,
),
);
let reported = err.emit();
return Err(reported);
}
_ => (),
}
}
@ -1095,6 +1198,8 @@ crate fn compare_ty_impl<'tcx>(
let _: Result<(), ErrorGuaranteed> = (|| {
compare_number_of_generics(tcx, impl_ty, impl_ty_span, trait_ty, trait_item_span)?;
compare_generic_param_kinds(tcx, impl_ty, trait_ty, trait_item_span)?;
let sp = tcx.def_span(impl_ty.def_id);
compare_type_predicate_entailment(tcx, impl_ty, sp, trait_ty, impl_trait_ref)?;

25
src/test/ui/const-generics/defaults/mismatched_ty_const_in_trait_impl.rs Normal file
View File

@ -0,0 +1,25 @@
trait Trait {
fn foo<U>() {}
}
impl Trait for () {
fn foo<const M: u64>() {}
//~^ error: method `foo` has an incompatble generic parameter for trait
}
trait Other {
fn bar<const M: u8>() {}
}
impl Other for () {
fn bar<T>() {}
//~^ error: method `bar` has an incompatible generic parameter for trait
}
trait Uwu {
fn baz<const N: u32>() {}
}
impl Uwu for () {
fn baz<const N: i32>() {}
//~^ error: method `baz` has an incompatible generic parameter for trait
}
fn main() {}

52
src/test/ui/const-generics/defaults/mismatched_ty_const_in_trait_impl.stderr Normal file
View File

@ -0,0 +1,52 @@
error[E0049]: method `foo` has 0 type parameters but its trait declaration has 1 type parameter
--> $DIR/mismatched_ty_const_in_trait_impl.rs:5:12
|
LL | fn foo<U>() {}
| - expected 1 type parameter
...
LL | fn foo<const M: u64>() {}
| ^^^^^^^^^^^^ found 0 type parameters
error[E0049]: method `foo` has 1 const parameter but its trait declaration has 0 const parameters
--> $DIR/mismatched_ty_const_in_trait_impl.rs:5:12
|
LL | fn foo<U>() {}
| - expected 0 const parameters
...
LL | fn foo<const M: u64>() {}
| ^^^^^^^^^^^^ found 1 const parameter
error[E0049]: method `bar` has 1 type parameter but its trait declaration has 0 type parameters
--> $DIR/mismatched_ty_const_in_trait_impl.rs:13:12
|
LL | fn bar<const M: u8>() {}
| ----------- expected 0 type parameters
...
LL | fn bar<T>() {}
| ^ found 1 type parameter
error[E0049]: method `bar` has 0 const parameters but its trait declaration has 1 const parameter
--> $DIR/mismatched_ty_const_in_trait_impl.rs:13:12
|
LL | fn bar<const M: u8>() {}
| ----------- expected 1 const parameter
...
LL | fn bar<T>() {}
| ^ found 0 const parameters
error[E0053]: method `baz` has an incompatible const parameter type for trait
--> $DIR/mismatched_ty_const_in_trait_impl.rs:21:12
|
LL | fn baz<const N: i32>() {}
| ^^^^^^^^^^^^
|
note: the const parameter `N` has type `i32`, but the declaration in trait `Uwu::baz` has type `u32`
--> $DIR/mismatched_ty_const_in_trait_impl.rs:18:12
|
LL | fn baz<const N: u32>() {}
| ^^^^^^^^^^^^
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0049, E0053.
For more information about an error, try `rustc --explain E0049`.

12
src/test/ui/generic-associated-types/const_params_have_right_type.rs Normal file
View File

@ -0,0 +1,12 @@
#![feature(generic_associated_types)]
trait Trait {
type Foo<const N: u8>;
}
impl Trait for () {
type Foo<const N: u64> = u32;
//~^ error: associated type `Foo` has an incompatible const parameter type
}
fn main() {}

15
src/test/ui/generic-associated-types/const_params_have_right_type.stderr Normal file
View File

@ -0,0 +1,15 @@
error[E0053]: associated type `Foo` has an incompatible const parameter type for trait
--> $DIR/const_params_have_right_type.rs:8:14
|
LL | type Foo<const N: u64> = u32;
| ^^^^^^^^^^^^
|
note: the const parameter `N` has type `u64`, but the declaration in trait `Trait::Foo` has type `u8`
--> $DIR/const_params_have_right_type.rs:4:14
|
LL | type Foo<const N: u8>;
| ^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0053`.