}
/// The selection process begins by considering all impls, where
-/// clauses, and so forth that might resolve an obligation. Sometimes
+/// clauses, and so forth that might resolve an obligation. Sometimes
/// we'll be able to say definitively that (e.g.) an impl does not
/// apply to the obligation: perhaps it is defined for `usize` but the
/// obligation is for `int`. In that case, we drop the impl out of the
-/// list. But the other cases are considered *candidates*.
+/// list. But the other cases are considered *candidates*.
///
/// For selection to succeed, there must be exactly one matching
/// candidate. If the obligation is fully known, this is guaranteed
/// - `EvaluatedToErr` implies `EvaluatedToRecur`
/// - the "union" of evaluation results is equal to their maximum -
/// all the "potential success" candidates can potentially succeed,
-/// so they are no-ops when unioned with a definite error, and within
+/// so they are noops when unioned with a definite error, and within
/// the categories it's easy to see that the unions are correct.
pub enum EvaluationResult {
/// Evaluation successful
/// ```
///
/// When we try to prove it, we first go the first option, which
- /// recurses. This shows us that the impl is "useless" - it won't
+ /// recurses. This shows us that the impl is "useless" -- it won't
/// tell us that `T: Trait` unless it already implemented `Trait`
/// by some other means. However, that does not prevent `T: Trait`
/// does not hold, because of the bound (which can indeed be satisfied
/// by `SomeUnsizedType` from another crate).
- ///
- /// FIXME: when an `EvaluatedToRecur` goes past its parent root, we
- /// ought to convert it to an `EvaluatedToErr`, because we know
- /// there definitely isn't a proof tree for that obligation. Not
- /// doing so is still sound - there isn't any proof tree, so the
- /// branch still can't be a part of a minimal one - but does not
- /// re-enable caching.
+ //
+ // FIXME: when an `EvaluatedToRecur` goes past its parent root, we
+ // ought to convert it to an `EvaluatedToErr`, because we know
+ // there definitely isn't a proof tree for that obligation. Not
+ // doing so is still sound -- there isn't any proof tree, so the
+ // branch still can't be a part of a minimal one -- but does not re-enable caching.
EvaluatedToRecur,
- /// Evaluation failed
+ /// Evaluation failed.
EvaluatedToErr,
}
impl EvaluationResult {
- /// True if this evaluation result is known to apply, even
+ /// Returns `true` if this evaluation result is known to apply, even
/// considering outlives constraints.
pub fn must_apply_considering_regions(self) -> bool {
self == EvaluatedToOk
}
- /// True if this evaluation result is known to apply, ignoring
+ /// Returns `true` if this evaluation result is known to apply, ignoring
/// outlives constraints.
pub fn must_apply_modulo_regions(self) -> bool {
self <= EvaluatedToOkModuloRegions
/// 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,
+ /// - is a defaulted trait,
+ /// - it also appears in the backtrace at some position `X`,
/// - all the predicates at positions `X..` between `X` an the top are
/// also defaulted traits.
pub fn coinductive_match<I>(&mut self, cycle: I) -> bool
}
/// Further evaluate `candidate` to decide whether all type parameters match and whether nested
- /// obligations are met. Returns true if `candidate` remains viable after this further
+ /// obligations are met. Returns whether `candidate` remains viable after this further
/// scrutiny.
fn evaluate_candidate<'o>(
&mut self,
}
}
- /// Returns true if the global caches can be used.
+ /// Returns `true` if the global caches can be used.
/// Do note that if the type itself is not in the
/// global tcx, the local caches will be used.
fn can_use_global_caches(&self, param_env: ty::ParamEnv<'tcx>) -> bool {
Ok(())
}
- /// Check for the artificial impl that the compiler will create for an obligation like `X :
+ /// Checks for the artificial impl that the compiler will create for an obligation like `X :
/// FnMut<..>` where `X` is a closure type.
///
/// Note: the type parameters on a closure candidate are modeled as *output* type
// type variables and then we also attempt to evaluate recursive
// bounds to see if they are satisfied.
- /// Returns true if `victim` should be dropped in favor of
- /// `other`. Generally speaking we will drop duplicate
+ /// Returns `true` if `victim` should be dropped in favor of
+ /// `other`. Generally speaking we will drop duplicate
/// candidates and prefer where-clause candidates.
///
/// See the comment for "SelectionCandidate" for more details.
/// we currently treat the input type parameters on the trait as
/// outputs. This means that when we have a match we have only
/// considered the self type, so we have to go back and make sure
- /// to relate the argument types too. This is kind of wrong, but
+ /// to relate the argument types too. This is kind of wrong, but
/// since we control the full set of impls, also not that wrong,
/// and it DOES yield better error messages (since we don't report
/// errors as if there is no applicable impl, but rather report
/// impl Fn(int) for Closure { ... }
///
/// Now imagine our obligation is `Fn(usize) for Closure`. So far
- /// we have matched the self-type `Closure`. At this point we'll
+ /// we have matched the self type `Closure`. At this point we'll
/// compare the `int` to `usize` and generate an error.
///
/// Note that this checking occurs *after* the impl has selected,
}
/// Normalize `where_clause_trait_ref` and try to match it against
- /// `obligation`. If successful, return any predicates that
+ /// `obligation`. If successful, return any predicates that
/// result from the normalization. Normalization is necessary
/// because where-clauses are stored in the parameter environment
/// unnormalized.
projects / rust.git / blobdiff