Struct rustc_hir_analysis::collect::ItemCtxt
source · pub struct ItemCtxt<'tcx> {
tcx: TyCtxt<'tcx>,
item_def_id: LocalDefId,
}
Expand description
Context specific to some particular item. This is what implements
AstConv
.
ItemCtxt
vs FnCtxt
ItemCtxt
is primarily used to type-check item signatures and lower them
from HIR to their ty::Ty
representation, which is exposed using AstConv
.
It’s also used for the bodies of items like structs where the body (the fields)
are just signatures.
This is in contrast to FnCtxt
, which is used to type-check bodies of
functions, closures, and const
s – anywhere that expressions and statements show up.
An important thing to note is that ItemCtxt
does no inference – it has no InferCtxt
–
while FnCtxt
does do inference.
Trait predicates
ItemCtxt
has information about the predicates that are defined
on the trait. Unfortunately, this predicate information is
available in various different forms at various points in the
process. So we can’t just store a pointer to e.g., the AST or the
parsed ty form, we have to be more flexible. To this end, the
ItemCtxt
is parameterized by a DefId
that it uses to satisfy
get_type_parameter_bounds
requests, drawing the information from
the AST (hir::Generics
), recursively.
Fields§
§tcx: TyCtxt<'tcx>
§item_def_id: LocalDefId
Implementations§
source§impl<'tcx> ItemCtxt<'tcx>
impl<'tcx> ItemCtxt<'tcx>
sourcefn type_parameter_bounds_in_generics(
&self,
ast_generics: &'tcx Generics<'tcx>,
param_def_id: LocalDefId,
ty: Ty<'tcx>,
filter: PredicateFilter
) -> Vec<(Clause<'tcx>, Span)>
fn type_parameter_bounds_in_generics( &self, ast_generics: &'tcx Generics<'tcx>, param_def_id: LocalDefId, ty: Ty<'tcx>, filter: PredicateFilter ) -> Vec<(Clause<'tcx>, Span)>
Finds bounds from hir::Generics
. This requires scanning through the
AST. We do this to avoid having to convert all the bounds, which
would create artificial cycles. Instead, we can only convert the
bounds for a type parameter X
if X::Foo
is used.
fn bound_defines_assoc_item( &self, b: &GenericBound<'_>, assoc_name: Ident ) -> bool
Trait Implementations§
source§impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx>
impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx>
fn tcx(&self) -> TyCtxt<'tcx>
fn item_def_id(&self) -> DefId
source§fn get_type_parameter_bounds(
&self,
span: Span,
def_id: LocalDefId,
assoc_name: Ident
) -> GenericPredicates<'tcx>
fn get_type_parameter_bounds( &self, span: Span, def_id: LocalDefId, assoc_name: Ident ) -> GenericPredicates<'tcx>
X: Foo<T>
, where X
is a type parameter X
with the given id def_id
and T
matches assoc_name
. This is a subset of the full set of
predicates. Read moresource§fn re_infer(&self, _: Option<&GenericParamDef>, _: Span) -> Option<Region<'tcx>>
fn re_infer(&self, _: Option<&GenericParamDef>, _: Span) -> Option<Region<'tcx>>
source§fn allow_ty_infer(&self) -> bool
fn allow_ty_infer(&self) -> bool
true
if _
is allowed in type signatures in the current context.source§fn ty_infer(&self, _: Option<&GenericParamDef>, span: Span) -> Ty<'tcx>
fn ty_infer(&self, _: Option<&GenericParamDef>, span: Span) -> Ty<'tcx>
source§fn ct_infer(
&self,
ty: Ty<'tcx>,
_: Option<&GenericParamDef>,
span: Span
) -> Const<'tcx>
fn ct_infer( &self, ty: Ty<'tcx>, _: Option<&GenericParamDef>, span: Span ) -> Const<'tcx>
source§fn projected_ty_from_poly_trait_ref(
&self,
span: Span,
item_def_id: DefId,
item_segment: &PathSegment<'_>,
poly_trait_ref: PolyTraitRef<'tcx>
) -> Ty<'tcx>
fn projected_ty_from_poly_trait_ref( &self, span: Span, item_def_id: DefId, item_segment: &PathSegment<'_>, poly_trait_ref: PolyTraitRef<'tcx> ) -> Ty<'tcx>
source§fn probe_adt(&self, _span: Span, ty: Ty<'tcx>) -> Option<AdtDef<'tcx>>
fn probe_adt(&self, _span: Span, ty: Ty<'tcx>) -> Option<AdtDef<'tcx>>
AdtDef
if ty
is an ADT.
Note that ty
might be a projection type that needs normalization.
This used to get the enum variants in scope of the type.
For example, Self::A
could refer to an associated type
or to an enum variant depending on the result of this function.source§fn set_tainted_by_errors(&self, _: ErrorGuaranteed)
fn set_tainted_by_errors(&self, _: ErrorGuaranteed)
fn record_ty(&self, _hir_id: HirId, _ty: Ty<'tcx>, _span: Span)
fn infcx(&self) -> Option<&InferCtxt<'tcx>>
fn astconv(&self) -> &dyn AstConv<'tcx>where Self: Sized,
Auto Trait Implementations§
impl<'tcx> !RefUnwindSafe for ItemCtxt<'tcx>
impl<'tcx> !Send for ItemCtxt<'tcx>
impl<'tcx> !Sync for ItemCtxt<'tcx>
impl<'tcx> Unpin for ItemCtxt<'tcx>
impl<'tcx> !UnwindSafe for ItemCtxt<'tcx>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Layout§
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...)
attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.
Size: 16 bytes