pub trait DropElaborator<'a, 'tcx>: Debug {
type Path: Copy + Debug;
// Required methods
fn patch(&mut self) -> &mut MirPatch<'tcx>;
fn body(&self) -> &'a Body<'tcx>;
fn tcx(&self) -> TyCtxt<'tcx>;
fn param_env(&self) -> ParamEnv<'tcx>;
fn drop_style(&self, path: Self::Path, mode: DropFlagMode) -> DropStyle;
fn get_drop_flag(&mut self, path: Self::Path) -> Option<Operand<'tcx>>;
fn clear_drop_flag(
&mut self,
location: Location,
path: Self::Path,
mode: DropFlagMode,
);
fn field_subpath(
&self,
path: Self::Path,
field: FieldIdx,
) -> Option<Self::Path>;
fn deref_subpath(&self, path: Self::Path) -> Option<Self::Path>;
fn downcast_subpath(
&self,
path: Self::Path,
variant: VariantIdx,
) -> Option<Self::Path>;
fn array_subpath(
&self,
path: Self::Path,
index: u64,
size: u64,
) -> Option<Self::Path>;
}
Required Associated Types§
sourcetype Path: Copy + Debug
type Path: Copy + Debug
The type representing paths that can be moved out of.
Users can move out of individual fields of a struct, such as a.b.c
. This type is used to
represent such move paths. Sometimes tracking individual move paths is not necessary, in
which case this may be set to (for example) ()
.
Required Methods§
fn patch(&mut self) -> &mut MirPatch<'tcx>
fn body(&self) -> &'a Body<'tcx>
fn tcx(&self) -> TyCtxt<'tcx>
fn param_env(&self) -> ParamEnv<'tcx>
sourcefn drop_style(&self, path: Self::Path, mode: DropFlagMode) -> DropStyle
fn drop_style(&self, path: Self::Path, mode: DropFlagMode) -> DropStyle
Returns how path
should be dropped, given mode
.
sourcefn get_drop_flag(&mut self, path: Self::Path) -> Option<Operand<'tcx>>
fn get_drop_flag(&mut self, path: Self::Path) -> Option<Operand<'tcx>>
Returns the drop flag of path
as a MIR Operand
(or None
if path
has no drop flag).
sourcefn clear_drop_flag(
&mut self,
location: Location,
path: Self::Path,
mode: DropFlagMode,
)
fn clear_drop_flag( &mut self, location: Location, path: Self::Path, mode: DropFlagMode, )
Modifies the MIR patch so that the drop flag of path
(if any) is cleared at location
.
If mode
is deep, drop flags of all child paths should also be cleared by inserting
additional statements.
sourcefn field_subpath(&self, path: Self::Path, field: FieldIdx) -> Option<Self::Path>
fn field_subpath(&self, path: Self::Path, field: FieldIdx) -> Option<Self::Path>
Returns the subpath of a field of path
(or None
if there is no dedicated subpath).
If this returns None
, field
will not get a dedicated drop flag.
sourcefn deref_subpath(&self, path: Self::Path) -> Option<Self::Path>
fn deref_subpath(&self, path: Self::Path) -> Option<Self::Path>
Returns the subpath of a dereference of path
(or None
if there is no dedicated subpath).
If this returns None
, *path
will not get a dedicated drop flag.
This is only relevant for Box<T>
, where the contained T
can be moved out of the box.
sourcefn downcast_subpath(
&self,
path: Self::Path,
variant: VariantIdx,
) -> Option<Self::Path>
fn downcast_subpath( &self, path: Self::Path, variant: VariantIdx, ) -> Option<Self::Path>
Returns the subpath of downcasting path
to one of its variants.
If this returns None
, the downcast of path
will not get a dedicated drop flag.
sourcefn array_subpath(
&self,
path: Self::Path,
index: u64,
size: u64,
) -> Option<Self::Path>
fn array_subpath( &self, path: Self::Path, index: u64, size: u64, ) -> Option<Self::Path>
Returns the subpath of indexing a fixed-size array path
.
If this returns None
, elements of path
will not get a dedicated drop flag.
This is only relevant for array patterns, which can move out of individual array elements.