Struct BodyRoot 

pub struct BodyRoot<'tcx> {
    pub body: Body<'tcx>,
    pub promoted: IndexVec<Promoted, Body<'tcx>>,
    pub infcx: InferCtxt<'tcx>,
    pub borrow_set: BorrowSet<'tcx>,
    pub region_inference_context: RegionInferenceContext<'tcx>,
}

Fields

body: Body<'tcx>

promoted: IndexVec<Promoted, Body<'tcx>>

infcx: InferCtxt<'tcx>

During borrow checking, rustc generates fresh region variable ids for each structurally different position in a type. For example, given a function

fn foo<'a, 'b>(x: &'a S<'a>, y: &'b u32)

rustc will generate variables ?2 and ?3 for the universal regions 'a and 'b (the variable ?0 correspond to 'static and ?1 to the implicit lifetime of the function body). Additionally, it will assign x type &‘?4 S<’?5>andytype&’?6 u32` (together with some constraints relating region variables). Unfortunately, we cannot recover the exact region variables rustc used.

The exact ids picked for 'a and 'b are not too relevant to us, the important part is the regions used in the types of x and y. To work around this, we generate fresh regions variables for the function signature, different from the ones sued by rustc. To recover the correct regions, whenever there’s an assignment of a refinement type T to a variable with (unrefined) Rust type S, we match both types to infer a region substitution. For this to work, we need to give a different variable id to every position in T. To avoid clashes, we need to use fresh ids, so we start enumerating from the last id generated by borrow checking.

To do that, we replicate the InferCtxt use for mir typeck by generating region variables for every region in the RegionInferenceContext. The InferCtxt is then used to generate new region variables.

The ids generated during refinement type checking are purely instrumental and temporary, they should never appear in a type bound in the environment.

Besides generating ids when checking a function’s body, we also need to generate fresh ids at function calls.

Additionally, the InferCtxt is used during type projection normalization.

borrow_set: BorrowSet<'tcx>

The set of borrows occurring in body with data about them.

region_inference_context: RegionInferenceContext<'tcx>

Context generated during borrowck, intended to be passed to [calculate_borrows_out_of_scope_at_location].

Implementations

impl<'tcx> BodyRoot<'tcx>

pub fn body(&self) -> &Body<'tcx>

pub fn calculate_borrows_out_of_scope_at_location( &self, ) -> FxIndexMap<Location, Vec<BorrowIndex>>

pub fn borrow_data(&self, idx: BorrowIndex) -> &BorrowData<'tcx>

impl<'tcx> BodyRoot<'tcx>

pub fn new( borrow_set: BorrowSet<'tcx>, region_inference_context: RegionInferenceContext<'tcx>, infcx: InferCtxt<'tcx>, body: Body<'tcx>, promoted: IndexVec<Promoted, Body<'tcx>>, ) -> Self