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Auto merge of rust-lang#118968 - aliemjay:canon-static, r=lcnr
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unify query canonicalization mode

Exclude from canonicalization only the static lifetimes that appear in the param env because of rust-lang#118965 . Any other occurrence can be canonicalized safely AFAICT.

r? `@lcnr`
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bors committed Jan 9, 2024
2 parents dc64103 + 707c4f9 commit be00c5a
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Showing 8 changed files with 35 additions and 75 deletions.
83 changes: 27 additions & 56 deletions compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,33 @@ impl<'tcx> InferCtxt<'tcx> {
where
V: TypeFoldable<TyCtxt<'tcx>>,
{
self.canonicalize_query_with_mode(value, query_state, &CanonicalizeAllFreeRegions)
let (param_env, value) = value.into_parts();
let param_env = self.tcx.canonical_param_env_cache.get_or_insert(
self.tcx,
param_env,
query_state,
|tcx, param_env, query_state| {
// FIXME(#118965): We don't canonicalize the static lifetimes that appear in the
// `param_env` beacause they are treated differently by trait selection.
Canonicalizer::canonicalize(
param_env,
None,
tcx,
&CanonicalizeFreeRegionsOtherThanStatic,
query_state,
)
},
);

Canonicalizer::canonicalize_with_base(
param_env,
value,
Some(self),
self.tcx,
&CanonicalizeAllFreeRegions,
query_state,
)
.unchecked_map(|(param_env, value)| param_env.and(value))
}

/// Canonicalizes a query *response* `V`. When we canonicalize a
Expand Down Expand Up @@ -96,61 +122,6 @@ impl<'tcx> InferCtxt<'tcx> {
&mut query_state,
)
}

/// A variant of `canonicalize_query` that does not
/// canonicalize `'static`. This is useful when
/// the query implementation can perform more efficient
/// handling of `'static` regions (e.g. trait evaluation).
pub fn canonicalize_query_keep_static<V>(
&self,
value: ty::ParamEnvAnd<'tcx, V>,
query_state: &mut OriginalQueryValues<'tcx>,
) -> Canonical<'tcx, ty::ParamEnvAnd<'tcx, V>>
where
V: TypeFoldable<TyCtxt<'tcx>>,
{
self.canonicalize_query_with_mode(
value,
query_state,
&CanonicalizeFreeRegionsOtherThanStatic,
)
}

fn canonicalize_query_with_mode<V>(
&self,
value: ty::ParamEnvAnd<'tcx, V>,
query_state: &mut OriginalQueryValues<'tcx>,
canonicalize_region_mode: &dyn CanonicalizeMode,
) -> Canonical<'tcx, ty::ParamEnvAnd<'tcx, V>>
where
V: TypeFoldable<TyCtxt<'tcx>>,
{
let (param_env, value) = value.into_parts();
let base = self.tcx.canonical_param_env_cache.get_or_insert(
self.tcx,
param_env,
query_state,
|tcx, param_env, query_state| {
Canonicalizer::canonicalize(
param_env,
None,
tcx,
&CanonicalizeFreeRegionsOtherThanStatic,
query_state,
)
},
);

Canonicalizer::canonicalize_with_base(
base,
value,
Some(self),
self.tcx,
canonicalize_region_mode,
query_state,
)
.unchecked_map(|(param_env, value)| param_env.and(value))
}
}

/// Controls how we canonicalize "free regions" that are not inference
Expand Down
3 changes: 1 addition & 2 deletions compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
Original file line number Diff line number Diff line change
Expand Up @@ -65,8 +65,7 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> {
assert!(!ty.has_non_region_infer());

let mut canonical_var_values = OriginalQueryValues::default();
let canonical_ty =
self.canonicalize_query_keep_static(param_env.and(ty), &mut canonical_var_values);
let canonical_ty = self.canonicalize_query(param_env.and(ty), &mut canonical_var_values);
let Ok(canonical_result) = self.tcx.implied_outlives_bounds(canonical_ty) else {
return vec![];
};
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -87,10 +87,8 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
})
} else {
assert!(!self.intercrate);
let c_pred = self.canonicalize_query_keep_static(
param_env.and(obligation.predicate),
&mut _orig_values,
);
let c_pred =
self.canonicalize_query(param_env.and(obligation.predicate), &mut _orig_values);
self.tcx.at(obligation.cause.span()).evaluate_obligation(c_pred)
}
}
Expand Down
5 changes: 1 addition & 4 deletions compiler/rustc_trait_selection/src/traits/query/normalize.rs
Original file line number Diff line number Diff line change
Expand Up @@ -272,10 +272,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx>
let data = data.try_fold_with(self)?;

let mut orig_values = OriginalQueryValues::default();
// HACK(matthewjasper) `'static` is special-cased in selection,
// so we cannot canonicalize it.
let c_data = infcx
.canonicalize_query_keep_static(self.param_env.and(data), &mut orig_values);
let c_data = infcx.canonicalize_query(self.param_env.and(data), &mut orig_values);
debug!("QueryNormalizer: c_data = {:#?}", c_data);
debug!("QueryNormalizer: orig_values = {:#?}", orig_values);
let result = match kind {
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -111,14 +111,9 @@ pub trait QueryTypeOp<'tcx>: fmt::Debug + Copy + TypeFoldable<TyCtxt<'tcx>> + 't
return Ok((result, None, vec![], Certainty::Proven));
}

// FIXME(#33684) -- We need to use
// `canonicalize_query_keep_static` here because of things
// like the subtype query, which go awry around
// `'static` otherwise.
let mut canonical_var_values = OriginalQueryValues::default();
let old_param_env = query_key.param_env;
let canonical_self =
infcx.canonicalize_query_keep_static(query_key, &mut canonical_var_values);
let canonical_self = infcx.canonicalize_query(query_key, &mut canonical_var_values);
let canonical_result = Self::perform_query(infcx.tcx, canonical_self)?;

let InferOk { value, obligations } = infcx
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ error: implementation of `Deserialize` is not general enough
LL | assert_deserialize_owned::<&'static str>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Deserialize` is not general enough
|
= note: `&'static str` must implement `Deserialize<'0>`, for any lifetime `'0`...
= note: `&str` must implement `Deserialize<'0>`, for any lifetime `'0`...
= note: ...but `&str` actually implements `Deserialize<'1>`, for some specific lifetime `'1`

error: aborting due to 1 previous error
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/higher-ranked/trait-bounds/issue-59311.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ error: higher-ranked lifetime error
LL | v.t(|| {});
| ^^^^^
|
= note: could not prove `for<'a> &'a V: 'static`
= note: could not prove `for<'a> &'a V: 'b`

error: aborting due to 2 previous errors

2 changes: 1 addition & 1 deletion tests/ui/nll/issue-54302.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ error: implementation of `Deserialize` is not general enough
LL | assert_deserialize_owned::<&'static str>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ implementation of `Deserialize` is not general enough
|
= note: `&'static str` must implement `Deserialize<'0>`, for any lifetime `'0`...
= note: `&str` must implement `Deserialize<'0>`, for any lifetime `'0`...
= note: ...but `&str` actually implements `Deserialize<'1>`, for some specific lifetime `'1`

error: aborting due to 1 previous error
Expand Down

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