Move borrowed_box to its own module

This commit is contained in:
Yoshitomo Nakanishi 2021-02-12 15:22:07 +09:00
parent cc3ab1c0ec
commit 53d3ffe539
2 changed files with 127 additions and 113 deletions

View file

@ -0,0 +1,118 @@
use rustc_errors::Applicability;
use rustc_hir::{
self as hir, GenericArg, GenericBounds, GenericParamKind, HirId, Lifetime, MutTy, Mutability, Node, QPath,
SyntheticTyParamKind, TyKind,
};
use rustc_lint::LateContext;
use if_chain::if_chain;
use crate::utils::{match_path, paths, snippet, span_lint_and_sugg};
pub(super) fn check(
cx: &LateContext<'_>,
hir_ty: &hir::Ty<'_>,
is_local: bool,
lt: &Lifetime,
mut_ty: &MutTy<'_>,
) -> bool {
match mut_ty.ty.kind {
TyKind::Path(ref qpath) => {
let hir_id = mut_ty.ty.hir_id;
let def = cx.qpath_res(qpath, hir_id);
if_chain! {
if let Some(def_id) = def.opt_def_id();
if Some(def_id) == cx.tcx.lang_items().owned_box();
if let QPath::Resolved(None, ref path) = *qpath;
if let [ref bx] = *path.segments;
if let Some(ref params) = bx.args;
if !params.parenthesized;
if let Some(inner) = params.args.iter().find_map(|arg| match arg {
GenericArg::Type(ty) => Some(ty),
_ => None,
});
then {
if is_any_trait(inner) {
// Ignore `Box<Any>` types; see issue #1884 for details.
return false;
}
let ltopt = if lt.is_elided() {
String::new()
} else {
format!("{} ", lt.name.ident().as_str())
};
if mut_ty.mutbl == Mutability::Mut {
// Ignore `&mut Box<T>` types; see issue #2907 for
// details.
return false;
}
// When trait objects or opaque types have lifetime or auto-trait bounds,
// we need to add parentheses to avoid a syntax error due to its ambiguity.
// Originally reported as the issue #3128.
let inner_snippet = snippet(cx, inner.span, "..");
let suggestion = match &inner.kind {
TyKind::TraitObject(bounds, lt_bound) if bounds.len() > 1 || !lt_bound.is_elided() => {
format!("&{}({})", ltopt, &inner_snippet)
},
TyKind::Path(qpath)
if get_bounds_if_impl_trait(cx, qpath, inner.hir_id)
.map_or(false, |bounds| bounds.len() > 1) =>
{
format!("&{}({})", ltopt, &inner_snippet)
},
_ => format!("&{}{}", ltopt, &inner_snippet),
};
span_lint_and_sugg(
cx,
super::BORROWED_BOX,
hir_ty.span,
"you seem to be trying to use `&Box<T>`. Consider using just `&T`",
"try",
suggestion,
// To make this `MachineApplicable`, at least one needs to check if it isn't a trait item
// because the trait impls of it will break otherwise;
// and there may be other cases that result in invalid code.
// For example, type coercion doesn't work nicely.
Applicability::Unspecified,
);
return true;
}
};
false
},
_ => false,
}
}
// Returns true if given type is `Any` trait.
fn is_any_trait(t: &hir::Ty<'_>) -> bool {
if_chain! {
if let TyKind::TraitObject(ref traits, _) = t.kind;
if !traits.is_empty();
// Only Send/Sync can be used as additional traits, so it is enough to
// check only the first trait.
if match_path(&traits[0].trait_ref.path, &paths::ANY_TRAIT);
then {
return true;
}
}
false
}
fn get_bounds_if_impl_trait<'tcx>(cx: &LateContext<'tcx>, qpath: &QPath<'_>, id: HirId) -> Option<GenericBounds<'tcx>> {
if_chain! {
if let Some(did) = cx.qpath_res(qpath, id).opt_def_id();
if let Some(Node::GenericParam(generic_param)) = cx.tcx.hir().get_if_local(did);
if let GenericParamKind::Type { synthetic, .. } = generic_param.kind;
if synthetic == Some(SyntheticTyParamKind::ImplTrait);
then {
Some(generic_param.bounds)
} else {
None
}
}
}

View file

@ -1,5 +1,6 @@
#![allow(rustc::default_hash_types)]
mod borrowed_box;
mod box_vec;
mod linked_list;
mod option_option;
@ -18,9 +19,9 @@ use rustc_errors::{Applicability, DiagnosticBuilder};
use rustc_hir as hir;
use rustc_hir::intravisit::{walk_body, walk_expr, walk_ty, FnKind, NestedVisitorMap, Visitor};
use rustc_hir::{
BinOpKind, Block, Body, Expr, ExprKind, FnDecl, FnRetTy, FnSig, GenericArg, GenericBounds, GenericParamKind, HirId,
ImplItem, ImplItemKind, Item, ItemKind, Lifetime, Lit, Local, MatchSource, MutTy, Mutability, Node, QPath, Stmt,
StmtKind, SyntheticTyParamKind, TraitFn, TraitItem, TraitItemKind, TyKind, UnOp,
BinOpKind, Block, Body, Expr, ExprKind, FnDecl, FnRetTy, FnSig, GenericArg, GenericParamKind, HirId, ImplItem,
ImplItemKind, Item, ItemKind, Lit, Local, MatchSource, MutTy, Mutability, Node, QPath, Stmt, StmtKind, TraitFn,
TraitItem, TraitItemKind, TyKind, UnOp,
};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::hir::map::Map;
@ -376,7 +377,11 @@ impl Types {
QPath::LangItem(..) => {},
}
},
TyKind::Rptr(ref lt, ref mut_ty) => self.check_ty_rptr(cx, hir_ty, is_local, lt, mut_ty),
TyKind::Rptr(ref lt, ref mut_ty) => {
if !borrowed_box::check(cx, hir_ty, is_local, lt, mut_ty) {
self.check_ty(cx, &mut_ty.ty, is_local);
}
},
TyKind::Slice(ref ty) | TyKind::Array(ref ty, _) | TyKind::Ptr(MutTy { ref ty, .. }) => {
self.check_ty(cx, ty, is_local)
},
@ -388,115 +393,6 @@ impl Types {
_ => {},
}
}
fn check_ty_rptr(
&mut self,
cx: &LateContext<'_>,
hir_ty: &hir::Ty<'_>,
is_local: bool,
lt: &Lifetime,
mut_ty: &MutTy<'_>,
) {
match mut_ty.ty.kind {
TyKind::Path(ref qpath) => {
let hir_id = mut_ty.ty.hir_id;
let def = cx.qpath_res(qpath, hir_id);
if_chain! {
if let Some(def_id) = def.opt_def_id();
if Some(def_id) == cx.tcx.lang_items().owned_box();
if let QPath::Resolved(None, ref path) = *qpath;
if let [ref bx] = *path.segments;
if let Some(ref params) = bx.args;
if !params.parenthesized;
if let Some(inner) = params.args.iter().find_map(|arg| match arg {
GenericArg::Type(ty) => Some(ty),
_ => None,
});
then {
if is_any_trait(inner) {
// Ignore `Box<Any>` types; see issue #1884 for details.
return;
}
let ltopt = if lt.is_elided() {
String::new()
} else {
format!("{} ", lt.name.ident().as_str())
};
if mut_ty.mutbl == Mutability::Mut {
// Ignore `&mut Box<T>` types; see issue #2907 for
// details.
return;
}
// When trait objects or opaque types have lifetime or auto-trait bounds,
// we need to add parentheses to avoid a syntax error due to its ambiguity.
// Originally reported as the issue #3128.
let inner_snippet = snippet(cx, inner.span, "..");
let suggestion = match &inner.kind {
TyKind::TraitObject(bounds, lt_bound) if bounds.len() > 1 || !lt_bound.is_elided() => {
format!("&{}({})", ltopt, &inner_snippet)
},
TyKind::Path(qpath)
if get_bounds_if_impl_trait(cx, qpath, inner.hir_id)
.map_or(false, |bounds| bounds.len() > 1) =>
{
format!("&{}({})", ltopt, &inner_snippet)
},
_ => format!("&{}{}", ltopt, &inner_snippet),
};
span_lint_and_sugg(
cx,
BORROWED_BOX,
hir_ty.span,
"you seem to be trying to use `&Box<T>`. Consider using just `&T`",
"try",
suggestion,
// To make this `MachineApplicable`, at least one needs to check if it isn't a trait item
// because the trait impls of it will break otherwise;
// and there may be other cases that result in invalid code.
// For example, type coercion doesn't work nicely.
Applicability::Unspecified,
);
return; // don't recurse into the type
}
};
self.check_ty(cx, &mut_ty.ty, is_local);
},
_ => self.check_ty(cx, &mut_ty.ty, is_local),
}
}
}
// Returns true if given type is `Any` trait.
fn is_any_trait(t: &hir::Ty<'_>) -> bool {
if_chain! {
if let TyKind::TraitObject(ref traits, _) = t.kind;
if !traits.is_empty();
// Only Send/Sync can be used as additional traits, so it is enough to
// check only the first trait.
if match_path(&traits[0].trait_ref.path, &paths::ANY_TRAIT);
then {
return true;
}
}
false
}
fn get_bounds_if_impl_trait<'tcx>(cx: &LateContext<'tcx>, qpath: &QPath<'_>, id: HirId) -> Option<GenericBounds<'tcx>> {
if_chain! {
if let Some(did) = cx.qpath_res(qpath, id).opt_def_id();
if let Some(Node::GenericParam(generic_param)) = cx.tcx.hir().get_if_local(did);
if let GenericParamKind::Type { synthetic, .. } = generic_param.kind;
if synthetic == Some(SyntheticTyParamKind::ImplTrait);
then {
Some(generic_param.bounds)
} else {
None
}
}
}
declare_clippy_lint! {