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Use a yes/no enum instead of a bool.
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The bool's meaning wasn't obvious to me at some call sites.
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@oli-obk
oli-obk committed May 2, 2022
1 parent 5428983 commit 0349f8b
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Showing 2 changed files with 50 additions and 28 deletions.
4 changes: 2 additions & 2 deletions compiler/rustc_resolve/src/ident.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1179,7 +1179,7 @@ impl<'a> Resolver<'a> {
ConstantItemRibKind(trivial, _) => {
let features = self.session.features_untracked();
// HACK(min_const_generics): We currently only allow `N` or `{ N }`.
if !(trivial || features.generic_const_exprs) {
if !(trivial == HasGenericParams::Yes || features.generic_const_exprs) {
// HACK(min_const_generics): If we encounter `Self` in an anonymous constant
// we can't easily tell if it's generic at this stage, so we instead remember
// this and then enforce the self type to be concrete later on.
Expand Down Expand Up @@ -1267,7 +1267,7 @@ impl<'a> Resolver<'a> {
ConstantItemRibKind(trivial, _) => {
let features = self.session.features_untracked();
// HACK(min_const_generics): We currently only allow `N` or `{ N }`.
if !(trivial || features.generic_const_exprs) {
if !(trivial == HasGenericParams::Yes || features.generic_const_exprs) {
if let Some(span) = finalize {
self.report_error(
span,
Expand Down
74 changes: 48 additions & 26 deletions compiler/rustc_resolve/src/late.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -94,6 +94,12 @@ crate enum HasGenericParams {
No,
}

impl HasGenericParams {
fn force_yes_if(self, b: bool) -> Self {
if b { Self::Yes } else { self }
}
}

#[derive(Copy, Clone, Debug, Eq, PartialEq)]
crate enum ConstantItemKind {
Const,
Expand Down Expand Up @@ -125,9 +131,9 @@ crate enum RibKind<'a> {

/// We're in a constant item. Can't refer to dynamic stuff.
///
/// The `bool` indicates if this constant may reference generic parameters
/// and is used to only allow generic parameters to be used in trivial constant expressions.
ConstantItemRibKind(bool, Option<(Ident, ConstantItemKind)>),
/// The item may reference generic parameters in trivial constant expressions.
/// All other constants aren't allowed to use generic params at all.
ConstantItemRibKind(HasGenericParams, Option<(Ident, ConstantItemKind)>),

/// We passed through a module.
ModuleRibKind(Module<'a>),
Expand Down Expand Up @@ -826,19 +832,24 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
// Note that we might not be inside of an repeat expression here,
// but considering that `IsRepeatExpr` is only relevant for
// non-trivial constants this is doesn't matter.
self.with_constant_rib(IsRepeatExpr::No, true, None, |this| {
this.smart_resolve_path(
ty.id,
qself.as_ref(),
path,
PathSource::Expr(None),
);

if let Some(ref qself) = *qself {
this.visit_ty(&qself.ty);
}
this.visit_path(path, ty.id);
});
self.with_constant_rib(
IsRepeatExpr::No,
HasGenericParams::Yes,
None,
|this| {
this.smart_resolve_path(
ty.id,
qself.as_ref(),
path,
PathSource::Expr(None),
);

if let Some(ref qself) = *qself {
this.visit_ty(&qself.ty);
}
this.visit_path(path, ty.id);
},
);

self.diagnostic_metadata.currently_processing_generics = prev;
return;
Expand Down Expand Up @@ -1688,7 +1699,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
// not used as part of the type system, this is far less surprising.
this.with_constant_rib(
IsRepeatExpr::No,
true,
HasGenericParams::Yes,
None,
|this| this.visit_expr(expr),
);
Expand Down Expand Up @@ -1767,7 +1778,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
// so it doesn't matter whether this is a trivial constant.
this.with_constant_rib(
IsRepeatExpr::No,
true,
HasGenericParams::Yes,
Some((item.ident, constant_item_kind)),
|this| this.visit_expr(expr),
);
Expand Down Expand Up @@ -1913,20 +1924,23 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
// Note that we intentionally still forbid `[0; N + 1]` during
// name resolution so that we don't extend the future
// compat lint to new cases.
#[instrument(level = "debug", skip(self, f))]
fn with_constant_rib(
&mut self,
is_repeat: IsRepeatExpr,
is_trivial: bool,
may_use_generics: HasGenericParams,
item: Option<(Ident, ConstantItemKind)>,
f: impl FnOnce(&mut Self),
) {
debug!("with_constant_rib: is_repeat={:?} is_trivial={}", is_repeat, is_trivial);
self.with_rib(ValueNS, ConstantItemRibKind(is_trivial, item), |this| {
self.with_rib(ValueNS, ConstantItemRibKind(may_use_generics, item), |this| {
this.with_rib(
TypeNS,
ConstantItemRibKind(is_repeat == IsRepeatExpr::Yes || is_trivial, item),
ConstantItemRibKind(
may_use_generics.force_yes_if(is_repeat == IsRepeatExpr::Yes),
item,
),
|this| {
this.with_label_rib(ConstantItemRibKind(is_trivial, item), f);
this.with_label_rib(ConstantItemRibKind(may_use_generics, item), f);
},
)
});
Expand Down Expand Up @@ -2068,7 +2082,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
// not used as part of the type system, this is far less surprising.
this.with_constant_rib(
IsRepeatExpr::No,
true,
HasGenericParams::Yes,
None,
|this| {
visit::walk_assoc_item(
Expand Down Expand Up @@ -3081,7 +3095,11 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
debug!("resolve_anon_const {:?} is_repeat: {:?}", constant, is_repeat);
self.with_constant_rib(
is_repeat,
constant.value.is_potential_trivial_const_param(),
if constant.value.is_potential_trivial_const_param() {
HasGenericParams::Yes
} else {
HasGenericParams::No
},
None,
|this| visit::walk_anon_const(this, constant),
);
Expand Down Expand Up @@ -3184,7 +3202,11 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
if const_args.contains(&idx) {
self.with_constant_rib(
IsRepeatExpr::No,
argument.is_potential_trivial_const_param(),
if argument.is_potential_trivial_const_param() {
HasGenericParams::Yes
} else {
HasGenericParams::No
},
None,
|this| {
this.resolve_expr(argument, None);
Expand Down

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