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internal: allow ambiguous unsize coercion.

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This commit is contained in:
Dawer 2021-06-09 11:49:12 +05:00
parent 3981373b93
commit 72002b401d
1 changed files with 9 additions and 6 deletions
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15
crates/hir_ty/src/infer/coerce.rs
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@ -17,8 +17,8 @@
Adjust, Adjustment, AutoBorrow, InferOk, InferResult, InferenceContext, OverloadedDeref,
PointerCast, TypeError, TypeMismatch,
},
static_lifetime, Canonical, DomainGoal, FnPointer, FnSig, InEnvironment, Interner, Solution,
Substitution, Ty, TyBuilder, TyExt, TyKind,
static_lifetime, Canonical, DomainGoal, FnPointer, FnSig, Guidance, InEnvironment, Interner,
Solution, Substitution, Ty, TyBuilder, TyExt, TyKind,
};
pub(crate) type CoerceResult = Result<InferOk<(Vec<Adjustment>, Ty)>, TypeError>;
@ -541,7 +541,7 @@ fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> CoerceResult {
_ => return Err(TypeError),
};
let trait_ref = {
let coerce_unsized_tref = {
let b = TyBuilder::trait_ref(self.db, coerce_unsized_trait);
if b.remaining() != 2 {
// The CoerceUnsized trait should have two generic params: Self and T.
@ -551,7 +551,7 @@ fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> CoerceResult {
};
let goal: InEnvironment<DomainGoal> =
InEnvironment::new(&self.trait_env.env, trait_ref.cast(&Interner));
InEnvironment::new(&self.trait_env.env, coerce_unsized_tref.cast(&Interner));
let canonicalized = self.canonicalize(goal);
@ -575,8 +575,11 @@ fn try_coerce_unsized(&mut self, from_ty: &Ty, to_ty: &Ty) -> CoerceResult {
},
);
}
// FIXME: should we accept ambiguous results here?
_ => return Err(TypeError),
Solution::Ambig(guidance) => {
if let Guidance::Definite(subst) = guidance {
canonicalized.apply_solution(&mut self.table, subst);
}
}
};
let unsize =
Adjustment { kind: Adjust::Pointer(PointerCast::Unsize), target: to_ty.clone() };