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Rollup merge of #96854 - jackh726:subst-cleanup, r=compiler-errors

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Some subst cleanup

Two separate things here. Both changes are useful for some refactoring I'm doing to add an "EarlyBinder" newtype. (Part of chalkification).

1) Remove `subst_spanned` and just use `subst`. It wasn't used much anyways. In practice, I think we can probably get most of the info just from the actual error message. If not, outputting logs should do the trick. (The specific line probably wouldn't help much anyways).

2) Call `.subst()` before `replace_bound_vars_with_fresh_vars` and `erase_late_bound_regions` in three places that do the opposite. I think there might have been some time in the past that the order here matter for something, but this shouldn't be the case anymore. Conceptually, it makes more sense to the of the *early bound* vars on `fn`s as "outside" the late bound vars.
This commit is contained in:
Matthias Krüger 2022-05-09 18:45:39 +02:00 • committed by GitHub
commit 0e00ed5f48
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6 changed files with 26 additions and 73 deletions
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10
compiler/rustc_typeck/src/astconv/mod.rs
View file

@ -523,11 +523,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
self.astconv
.normalize_ty(
self.span,
tcx.at(self.span).type_of(param.def_id).subst_spanned(
tcx,
substs,
Some(self.span),
),
tcx.at(self.span).type_of(param.def_id).subst(tcx, substs),
)
.into()
}
@ -547,9 +543,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
GenericParamDefKind::Const { has_default } => {
let ty = tcx.at(self.span).type_of(param.def_id);
if !infer_args && has_default {
tcx.const_param_default(param.def_id)
.subst_spanned(tcx, substs.unwrap(), Some(self.span))
.into()
tcx.const_param_default(param.def_id).subst(tcx, substs.unwrap()).into()
} else {
if infer_args {
self.astconv.ct_infer(ty, Some(param), self.span).into()

9
compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
View file

@ -1403,10 +1403,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// is missing.
let default = tcx.type_of(param.def_id);
self.fcx
.normalize_ty(
self.span,
default.subst_spanned(tcx, substs.unwrap(), Some(self.span)),
)
.normalize_ty(self.span, default.subst(tcx, substs.unwrap()))
.into()
} else {
// If no type arguments were provided, we have to infer them.
@ -1418,9 +1415,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
GenericParamDefKind::Const { has_default } => {
if !infer_args && has_default {
tcx.const_param_default(param.def_id)
.subst_spanned(tcx, substs.unwrap(), Some(self.span))
.into()
tcx.const_param_default(param.def_id).subst(tcx, substs.unwrap()).into()
} else {
self.fcx.var_for_def(self.span, param)
}

16
compiler/rustc_typeck/src/check/method/confirm.rs
View file

@ -462,19 +462,13 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
let sig = self.tcx.fn_sig(def_id);
// Instantiate late-bound regions and substitute the trait
// parameters into the method type to get the actual method type.
//
// N.B., instantiate late-bound regions first so that
// `instantiate_type_scheme` can normalize associated types that
// may reference those regions.
let method_sig = self.replace_bound_vars_with_fresh_vars(sig);
debug!("late-bound lifetimes from method instantiated, method_sig={:?}", method_sig);
let sig = sig.subst(self.tcx, all_substs);
debug!("type scheme substituted, sig={:?}", sig);
let method_sig = method_sig.subst(self.tcx, all_substs);
debug!("type scheme substituted, method_sig={:?}", method_sig);
let sig = self.replace_bound_vars_with_fresh_vars(sig);
debug!("late-bound lifetimes from method instantiated, sig={:?}", sig);
(method_sig, method_predicates)
(sig, method_predicates)
}
fn add_obligations(

2
compiler/rustc_typeck/src/check/method/mod.rs
View file

@ -461,8 +461,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// `instantiate_type_scheme` can normalize associated types that
// may reference those regions.
let fn_sig = tcx.fn_sig(def_id);
let fn_sig = self.replace_bound_vars_with_fresh_vars(span, infer::FnCall, fn_sig).0;
let fn_sig = fn_sig.subst(self.tcx, substs);
let fn_sig = self.replace_bound_vars_with_fresh_vars(span, infer::FnCall, fn_sig).0;
let InferOk { value, obligations: o } = if is_op {
self.normalize_op_associated_types_in_as_infer_ok(span, fn_sig, opt_input_expr)

14
compiler/rustc_typeck/src/check/method/probe.rs
View file

@ -1784,12 +1784,8 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
let generics = self.tcx.generics_of(method);
assert_eq!(substs.len(), generics.parent_count as usize);
// Erase any late-bound regions from the method and substitute
// in the values from the substitution.
let xform_fn_sig = self.erase_late_bound_regions(fn_sig);
if generics.params.is_empty() {
xform_fn_sig.subst(self.tcx, substs)
let xform_fn_sig = if generics.params.is_empty() {
fn_sig.subst(self.tcx, substs)
} else {
let substs = InternalSubsts::for_item(self.tcx, method, |param, _| {
let i = param.index as usize;
@ -1807,8 +1803,10 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}
});
xform_fn_sig.subst(self.tcx, substs)
}
fn_sig.subst(self.tcx, substs)
};
self.erase_late_bound_regions(xform_fn_sig)
}
/// Gets the type of an impl and generate substitutions with placeholders.