Struct rustc::traits::SelectionContext

pub struct SelectionContext<'cx, 'gcx: 'cx + 'tcx, 'tcx: 'cx> { /* fields omitted */ }

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Methods

impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx>

pub fn new(     infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx> ) -> SelectionContext<'cx, 'gcx, 'tcx>

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pub fn intercrate(     infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,     mode: IntercrateMode ) -> SelectionContext<'cx, 'gcx, 'tcx>

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pub fn with_negative(     infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,     allow_negative_impls: bool ) -> SelectionContext<'cx, 'gcx, 'tcx>

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pub fn enable_tracking_intercrate_ambiguity_causes(&mut self)

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Enables tracking of intercrate ambiguity causes. These are used in coherence to give improved diagnostics. We don't do this until we detect a coherence error because it can lead to false overflow results (#47139) and because it costs computation time.

Important traits for Vec<u8>

impl Write for Vec<u8>

pub fn take_intercrate_ambiguity_causes(     &mut self ) -> Vec<IntercrateAmbiguityCause>

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Gets the intercrate ambiguity causes collected since tracking was enabled and disables tracking at the same time. If tracking is not enabled, just returns an empty vector.

pub fn infcx(&self) -> &'cx InferCtxt<'cx, 'gcx, 'tcx>

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pub fn tcx(&self) -> TyCtxt<'cx, 'gcx, 'tcx>

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pub fn closure_typer(&self) -> &'cx InferCtxt<'cx, 'gcx, 'tcx>

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pub fn select(     &mut self,     obligation: &TraitObligation<'tcx> ) -> SelectionResult<'tcx, Selection<'tcx>>

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Attempts to satisfy the obligation. If successful, this will affect the surrounding type environment by performing unification.

pub fn evaluate_obligation(     &mut self,     obligation: &PredicateObligation<'tcx> ) -> bool

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Evaluates whether the obligation obligation can be satisfied (by any means).

pub fn evaluate_obligation_conservatively(     &mut self,     obligation: &PredicateObligation<'tcx> ) -> bool

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Evaluates whether the obligation obligation can be satisfied, and returns false if not certain. However, this is not entirely accurate if inference variables are involved.

pub fn coinductive_match<I>(&mut self, cycle: I) -> bool where     I: Iterator<Item = Predicate<'tcx>>,

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For defaulted traits, we use a co-inductive strategy to solve, so that recursion is ok. This routine returns true if the top of the stack (cycle[0]):

• is a defaulted trait, and
• it also appears in the backtrace at some position X; and,
• all the predicates at positions X.. between X an the top are also defaulted traits.

Trait Implementations