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5 - Make more use of let_chains
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@c410-f3r
c410-f3r committed Feb 28, 2022
1 parent 48132ca commit d956c8b
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Showing 5 changed files with 63 additions and 68 deletions.
30 changes: 14 additions & 16 deletions compiler/rustc_passes/src/check_attr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1113,22 +1113,20 @@ impl CheckAttrVisitor<'_> {
/// Warns against some misuses of `#[must_use]`
fn check_must_use(&self, hir_id: HirId, attr: &Attribute, span: Span, _target: Target) -> bool {
let node = self.tcx.hir().get(hir_id);
if let Some(fn_node) = node.fn_kind() {
if let rustc_hir::IsAsync::Async = fn_node.asyncness() {
self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, attr.span, |lint| {
lint.build(
"`must_use` attribute on `async` functions \
applies to the anonymous `Future` returned by the \
function, not the value within",
)
.span_label(
span,
"this attribute does nothing, the `Future`s \
returned by async functions are already `must_use`",
)
.emit();
});
}
if let Some(kind) = node.fn_kind() && let rustc_hir::IsAsync::Async = kind.asyncness() {
self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, attr.span, |lint| {
lint.build(
"`must_use` attribute on `async` functions \
applies to the anonymous `Future` returned by the \
function, not the value within",
)
.span_label(
span,
"this attribute does nothing, the `Future`s \
returned by async functions are already `must_use`",
)
.emit();
});
}

// For now, its always valid
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55 changes: 27 additions & 28 deletions compiler/rustc_passes/src/dead.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -683,34 +683,33 @@ impl<'tcx> DeadVisitor<'tcx> {
let descr = self.tcx.def_kind(def_id).descr(def_id.to_def_id());
let mut err = lint.build(&format!("{} is never {}: `{}`", descr, participle, name));
let hir = self.tcx.hir();
if let Some(encl_scope) = hir.get_enclosing_scope(id) {
if let Some(encl_def_id) = hir.opt_local_def_id(encl_scope) {
if let Some(ign_traits) = self.ignored_derived_traits.get(&encl_def_id) {
let traits_str = ign_traits
.iter()
.map(|(trait_id, _)| format!("`{}`", self.tcx.item_name(*trait_id)))
.collect::<Vec<_>>()
.join(" and ");
let plural_s = pluralize!(ign_traits.len());
let article = if ign_traits.len() > 1 { "" } else { "a " };
let is_are = if ign_traits.len() > 1 { "these are" } else { "this is" };
let msg = format!(
"`{}` has {}derived impl{} for the trait{} {}, but {} \
intentionally ignored during dead code analysis",
self.tcx.item_name(encl_def_id.to_def_id()),
article,
plural_s,
plural_s,
traits_str,
is_are
);
let multispan = ign_traits
.iter()
.map(|(_, impl_id)| self.tcx.def_span(*impl_id))
.collect::<Vec<_>>();
err.span_note(multispan, &msg);
}
}
if let Some(encl_scope) = hir.get_enclosing_scope(id)
&& let Some(encl_def_id) = hir.opt_local_def_id(encl_scope)
&& let Some(ign_traits) = self.ignored_derived_traits.get(&encl_def_id)
{
let traits_str = ign_traits
.iter()
.map(|(trait_id, _)| format!("`{}`", self.tcx.item_name(*trait_id)))
.collect::<Vec<_>>()
.join(" and ");
let plural_s = pluralize!(ign_traits.len());
let article = if ign_traits.len() > 1 { "" } else { "a " };
let is_are = if ign_traits.len() > 1 { "these are" } else { "this is" };
let msg = format!(
"`{}` has {}derived impl{} for the trait{} {}, but {} \
intentionally ignored during dead code analysis",
self.tcx.item_name(encl_def_id.to_def_id()),
article,
plural_s,
plural_s,
traits_str,
is_are
);
let multispan = ign_traits
.iter()
.map(|(_, impl_id)| self.tcx.def_span(*impl_id))
.collect::<Vec<_>>();
err.span_note(multispan, &msg);
}
err.emit();
});
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3 changes: 2 additions & 1 deletion compiler/rustc_passes/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,16 +4,17 @@
//!
//! This API is completely unstable and subject to change.

#![allow(rustc::potential_query_instability)]
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![feature(crate_visibility_modifier)]
#![feature(iter_intersperse)]
#![feature(let_else)]
#![feature(let_chains)]
#![feature(map_try_insert)]
#![feature(min_specialization)]
#![feature(nll)]
#![feature(try_blocks)]
#![recursion_limit = "256"]
#![allow(rustc::potential_query_instability)]

#[macro_use]
extern crate rustc_middle;
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11 changes: 5 additions & 6 deletions compiler/rustc_passes/src/liveness.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -332,12 +332,11 @@ impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
let def_id = local_def_id.to_def_id();

// Don't run unused pass for #[derive()]
if let Some(parent) = self.tcx.parent(def_id) {
if let DefKind::Impl = self.tcx.def_kind(parent.expect_local()) {
if self.tcx.has_attr(parent, sym::automatically_derived) {
return;
}
}
if let Some(parent) = self.tcx.parent(def_id)
&& let DefKind::Impl = self.tcx.def_kind(parent.expect_local())
&& self.tcx.has_attr(parent, sym::automatically_derived)
{
return;
}

// Don't run unused pass for #[naked]
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32 changes: 15 additions & 17 deletions compiler/rustc_passes/src/reachable.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -94,24 +94,22 @@ impl<'tcx> Visitor<'tcx> for ReachableContext<'tcx> {
_ => None,
};

if let Some(res) = res {
if let Some(def_id) = res.opt_def_id().and_then(|def_id| def_id.as_local()) {
if self.def_id_represents_local_inlined_item(def_id.to_def_id()) {
self.worklist.push(def_id);
} else {
match res {
// If this path leads to a constant, then we need to
// recurse into the constant to continue finding
// items that are reachable.
Res::Def(DefKind::Const | DefKind::AssocConst, _) => {
self.worklist.push(def_id);
}
if let Some(res) = res && let Some(def_id) = res.opt_def_id().and_then(|el| el.as_local()) {
if self.def_id_represents_local_inlined_item(def_id.to_def_id()) {
self.worklist.push(def_id);
} else {
match res {
// If this path leads to a constant, then we need to
// recurse into the constant to continue finding
// items that are reachable.
Res::Def(DefKind::Const | DefKind::AssocConst, _) => {
self.worklist.push(def_id);
}

// If this wasn't a static, then the destination is
// surely reachable.
_ => {
self.reachable_symbols.insert(def_id);
}
// If this wasn't a static, then the destination is
// surely reachable.
_ => {
self.reachable_symbols.insert(def_id);
}
}
}
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