Mirrors/rust-clippy
2
0
Fork 0
mirror of https://github.com/rust-lang/rust-clippy synced 2024-11-24 13:43:17 +00:00
Code Issues Projects Releases Packages Wiki Activity

refactor manual_filter

Browse source 
Move common functions to `manual_utils.rs`, better arm matching, use clippy utils `contains_unsafe_block`
This commit is contained in:
kraktus 2022-10-03 14:11:54 +02:00
parent 0958f9486b
commit b89ac0cefc
5 changed files with 311 additions and 333 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

76
clippy_lints/src/matches/manual_filter.rs
View file

@ -1,39 +1,20 @@
use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::ty::is_type_diagnostic_item; use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::visitors::contains_unsafe_block;
use clippy_utils::{is_res_lang_ctor, path_res, path_to_local_id}; use clippy_utils::{is_res_lang_ctor, path_res, path_to_local_id};
use rustc_hir::intravisit::{walk_expr, Visitor};
use rustc_hir::LangItem::OptionSome; use rustc_hir::LangItem::OptionSome;
use rustc_hir::{Arm, Block, BlockCheckMode, Expr, ExprKind, HirId, Pat, PatKind, UnsafeSource}; use rustc_hir::{Arm, Expr, ExprKind, HirId, Pat, PatKind};
use rustc_lint::LateContext; use rustc_lint::LateContext;
use rustc_span::{sym, SyntaxContext}; use rustc_span::{sym, SyntaxContext};
use super::manual_map::{check_with, SomeExpr}; use super::manual_utils::{check_with, SomeExpr};
use super::MANUAL_FILTER; use super::MANUAL_FILTER;
#[derive(Default)] // Function called on the <expr> of `[&+]Some((ref | ref mut) x) => <expr>`
struct NeedsUnsafeBlock(pub bool); // Need to check if it's of the form `<expr>=if <cond> {<then_expr>} else {<else_expr>}`
impl<'tcx> Visitor<'tcx> for NeedsUnsafeBlock {
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
match expr.kind {
ExprKind::Block(
Block {
rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
..
},
_,
) => {
self.0 = true;
},
_ => walk_expr(self, expr),
}
}
}
// Function called on the `expr` of `[&+]Some((ref | ref mut) x) => <expr>`
// Need to check if it's of the `if <cond> {<then_expr>} else {<else_expr>}`
// AND that only one `then/else_expr` resolves to `Some(x)` while the other resolves to `None` // AND that only one `then/else_expr` resolves to `Some(x)` while the other resolves to `None`
// return `cond` if // return the `cond` expression if so.
fn get_cond_expr<'tcx>( fn get_cond_expr<'tcx>(
cx: &LateContext<'tcx>, cx: &LateContext<'tcx>,
pat: &Pat<'_>, pat: &Pat<'_>,
@ -45,15 +26,13 @@ fn get_cond_expr<'tcx>(
if let ExprKind::If(cond, then_expr, Some(else_expr)) = block_expr.kind; if let ExprKind::If(cond, then_expr, Some(else_expr)) = block_expr.kind;
if let PatKind::Binding(_,target, ..) = pat.kind; if let PatKind::Binding(_,target, ..) = pat.kind;
if let (then_visitor, else_visitor) if let (then_visitor, else_visitor)
= (handle_if_or_else_expr(cx, target, ctxt, then_expr), = (is_some_expr(cx, target, ctxt, then_expr),
handle_if_or_else_expr(cx, target, ctxt, else_expr)); is_some_expr(cx, target, ctxt, else_expr));
if then_visitor != else_visitor; // check that one expr resolves to `Some(x)`, the other to `None` if then_visitor != else_visitor; // check that one expr resolves to `Some(x)`, the other to `None`
then { then {
let mut needs_unsafe_block = NeedsUnsafeBlock::default();
needs_unsafe_block.visit_expr(expr);
return Some(SomeExpr { return Some(SomeExpr {
expr: peels_blocks_incl_unsafe(cond.peel_drop_temps()), expr: peels_blocks_incl_unsafe(cond.peel_drop_temps()),
needs_unsafe_block: needs_unsafe_block.0, needs_unsafe_block: contains_unsafe_block(cx, expr),
needs_negated: !then_visitor // if the `then_expr` resolves to `None`, need to negate the cond needs_negated: !then_visitor // if the `then_expr` resolves to `None`, need to negate the cond
}) })
} }
@ -63,7 +42,7 @@ fn get_cond_expr<'tcx>(
fn peels_blocks_incl_unsafe_opt<'a>(expr: &'a Expr<'a>) -> Option<&'a Expr<'a>> { fn peels_blocks_incl_unsafe_opt<'a>(expr: &'a Expr<'a>) -> Option<&'a Expr<'a>> {
// we don't want to use `peel_blocks` here because we don't care if the block is unsafe, it's // we don't want to use `peel_blocks` here because we don't care if the block is unsafe, it's
// checked by `NeedsUnsafeBlock` // checked by `contains_unsafe_block`
if let ExprKind::Block(block, None) = expr.kind { if let ExprKind::Block(block, None) = expr.kind {
if block.stmts.is_empty() { if block.stmts.is_empty() {
return block.expr; return block.expr;
@ -76,23 +55,18 @@ fn peels_blocks_incl_unsafe<'a>(expr: &'a Expr<'a>) -> &'a Expr<'a> {
peels_blocks_incl_unsafe_opt(expr).unwrap_or(expr) peels_blocks_incl_unsafe_opt(expr).unwrap_or(expr)
} }
// function called for each <ifelse> expression: // function called for each <expr> expression:
// Some(x) => if <cond> { // Some(x) => if <cond> {
// <ifelse> // <expr>
// } else { // } else {
// <ifelse> // <expr>
// } // }
// Returns true if <ifelse> resolves to `Some(x)`, `false` otherwise // Returns true if <expr> resolves to `Some(x)`, `false` otherwise
fn handle_if_or_else_expr<'tcx>( fn is_some_expr<'tcx>(cx: &LateContext<'_>, target: HirId, ctxt: SyntaxContext, expr: &'tcx Expr<'_>) -> bool {
cx: &LateContext<'_>, if let Some(inner_expr) = peels_blocks_incl_unsafe_opt(expr) {
target: HirId,
ctxt: SyntaxContext,
if_or_else_expr: &'tcx Expr<'_>,
) -> bool {
if let Some(inner_expr) = peels_blocks_incl_unsafe_opt(if_or_else_expr) {
// there can be not statements in the block as they would be removed when switching to `.filter` // there can be not statements in the block as they would be removed when switching to `.filter`
if let ExprKind::Call(callee, [arg]) = inner_expr.kind { if let ExprKind::Call(callee, [arg]) = inner_expr.kind {
return ctxt == if_or_else_expr.span.ctxt() return ctxt == expr.span.ctxt()
&& is_res_lang_ctor(cx, path_res(cx, callee), OptionSome) && is_res_lang_ctor(cx, path_res(cx, callee), OptionSome)
&& path_to_local_id(arg, target); && path_to_local_id(arg, target);
} }
@ -119,15 +93,13 @@ pub(super) fn check_match<'tcx>(
expr: &'tcx Expr<'_>, expr: &'tcx Expr<'_>,
) { ) {
let ty = cx.typeck_results().expr_ty(expr); let ty = cx.typeck_results().expr_ty(expr);
if_chain! { if is_type_diagnostic_item(cx, ty, sym::Option)
if is_type_diagnostic_item(cx, ty, sym::Option); && let [first_arm, second_arm] = arms
if arms.len() == 2; && first_arm.guard.is_none()
if arms[0].guard.is_none(); && second_arm.guard.is_none()
if arms[1].guard.is_none(); {
then { check(cx, expr, scrutinee, first_arm.pat, first_arm.body, Some(second_arm.pat), second_arm.body);
check(cx, expr, scrutinee, arms[0].pat, arms[0].body, Some(arms[1].pat), arms[1].body)
} }
}
} }
pub(super) fn check_if_let<'tcx>( pub(super) fn check_if_let<'tcx>(

287
clippy_lints/src/matches/manual_map.rs
View file

@ -1,21 +1,13 @@
use super::manual_utils::{check_with, SomeExpr};
use super::MANUAL_MAP; use super::MANUAL_MAP;
use crate::{map_unit_fn::OPTION_MAP_UNIT_FN, matches::MATCH_AS_REF};
use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
use clippy_utils::ty::{is_copy, is_type_diagnostic_item, peel_mid_ty_refs_is_mutable, type_is_unsafe_function}; use clippy_utils::{is_res_lang_ctor, path_res};
use clippy_utils::{
can_move_expr_to_closure, is_else_clause, is_lint_allowed, is_res_lang_ctor, path_res, path_to_local_id, use rustc_hir::LangItem::OptionSome;
peel_blocks, peel_hir_expr_refs, peel_hir_expr_while, sugg::Sugg, CaptureKind, use rustc_hir::{Arm, Block, BlockCheckMode, Expr, ExprKind, Pat, UnsafeSource};
};
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_errors::Applicability;
use rustc_hir::LangItem::{OptionNone, OptionSome};
use rustc_hir::{
def::Res, Arm, BindingAnnotation, Block, BlockCheckMode, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path,
QPath, UnsafeSource,
};
use rustc_lint::LateContext; use rustc_lint::LateContext;
use rustc_span::{sym, SyntaxContext}; use rustc_span::SyntaxContext;
pub(super) fn check_match<'tcx>( pub(super) fn check_match<'tcx>(
cx: &LateContext<'tcx>, cx: &LateContext<'tcx>,
@ -83,266 +75,6 @@ fn check<'tcx>(
} }
} }
#[expect(clippy::too_many_arguments)]
#[expect(clippy::too_many_lines)]
pub(super) fn check_with<'tcx, F>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
scrutinee: &'tcx Expr<'_>,
then_pat: &'tcx Pat<'_>,
then_body: &'tcx Expr<'_>,
else_pat: Option<&'tcx Pat<'_>>,
else_body: &'tcx Expr<'_>,
get_some_expr_fn: F,
) -> Option<SuggInfo<'tcx>>
where
F: Fn(&LateContext<'tcx>, &'tcx Pat<'_>, &'tcx Expr<'_>, SyntaxContext) -> Option<SomeExpr<'tcx>>,
{
let (scrutinee_ty, ty_ref_count, ty_mutability) =
peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(scrutinee));
if !(is_type_diagnostic_item(cx, scrutinee_ty, sym::Option)
&& is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::Option))
{
return None;
}
let expr_ctxt = expr.span.ctxt();
let (some_expr, some_pat, pat_ref_count, is_wild_none) = match (
try_parse_pattern(cx, then_pat, expr_ctxt),
else_pat.map_or(Some(OptionPat::Wild), |p| try_parse_pattern(cx, p, expr_ctxt)),
) {
(Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_body) => {
(else_body, pattern, ref_count, true)
},
(Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_body) => {
(else_body, pattern, ref_count, false)
},
(Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild)) if is_none_expr(cx, else_body) => {
(then_body, pattern, ref_count, true)
},
(Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None)) if is_none_expr(cx, else_body) => {
(then_body, pattern, ref_count, false)
},
_ => return None,
};
// Top level or patterns aren't allowed in closures.
if matches!(some_pat.kind, PatKind::Or(_)) {
return None;
}
let some_expr = match get_some_expr_fn(cx, some_pat, some_expr, expr_ctxt) {
Some(expr) => expr,
None => return None,
};
// These two lints will go back and forth with each other.
if cx.typeck_results().expr_ty(some_expr.expr) == cx.tcx.types.unit
&& !is_lint_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id)
{
return None;
}
// `map` won't perform any adjustments.
if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() {
return None;
}
// Determine which binding mode to use.
let explicit_ref = some_pat.contains_explicit_ref_binding();
let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then_some(ty_mutability));
let as_ref_str = match binding_ref {
Some(Mutability::Mut) => ".as_mut()",
Some(Mutability::Not) => ".as_ref()",
None => "",
};
match can_move_expr_to_closure(cx, some_expr.expr) {
Some(captures) => {
// Check if captures the closure will need conflict with borrows made in the scrutinee.
// TODO: check all the references made in the scrutinee expression. This will require interacting
// with the borrow checker. Currently only `<local>[.<field>]*` is checked for.
if let Some(binding_ref_mutability) = binding_ref {
let e = peel_hir_expr_while(scrutinee, |e| match e.kind {
ExprKind::Field(e, _) | ExprKind::AddrOf(_, _, e) => Some(e),
_ => None,
});
if let ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(l), .. })) = e.kind {
match captures.get(l) {
Some(CaptureKind::Value | CaptureKind::Ref(Mutability::Mut)) => return None,
Some(CaptureKind::Ref(Mutability::Not)) if binding_ref_mutability == Mutability::Mut => {
return None;
},
Some(CaptureKind::Ref(Mutability::Not)) | None => (),
}
}
}
},
None => return None,
};
let mut app = Applicability::MachineApplicable;
// Remove address-of expressions from the scrutinee. Either `as_ref` will be called, or
// it's being passed by value.
let scrutinee = peel_hir_expr_refs(scrutinee).0;
let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app);
let scrutinee_str = if scrutinee.span.ctxt() == expr.span.ctxt() && scrutinee.precedence().order() < PREC_POSTFIX {
format!("({scrutinee_str})")
} else {
scrutinee_str.into()
};
let closure_expr_snip = some_expr.to_snippet_with_context(cx, expr_ctxt, &mut app);
let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind {
if_chain! {
if !some_expr.needs_unsafe_block;
if let Some(func) = can_pass_as_func(cx, id, some_expr.expr);
if func.span.ctxt() == some_expr.expr.span.ctxt();
then {
snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
} else {
if path_to_local_id(some_expr.expr, id)
&& !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id)
&& binding_ref.is_some()
{
return None;
}
// `ref` and `ref mut` annotations were handled earlier.
let annotation = if matches!(annotation, BindingAnnotation::MUT) {
"mut "
} else {
""
};
if some_expr.needs_unsafe_block {
format!("|{annotation}{some_binding}| unsafe {{ {closure_expr_snip} }}")
} else {
format!("|{annotation}{some_binding}| {closure_expr_snip}")
}
}
}
} else if !is_wild_none && explicit_ref.is_none() {
// TODO: handle explicit reference annotations.
let pat_snip = snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0;
if some_expr.needs_unsafe_block {
format!("|{pat_snip}| unsafe {{ {closure_expr_snip} }}")
} else {
format!("|{pat_snip}| {closure_expr_snip}")
}
} else {
// Refutable bindings and mixed reference annotations can't be handled by `map`.
return None;
};
// relies on the fact that Option<T>: Copy where T: copy
let scrutinee_impl_copy = is_copy(cx, scrutinee_ty);
Some(SuggInfo {
needs_brackets: else_pat.is_none() && is_else_clause(cx.tcx, expr),
scrutinee_impl_copy,
scrutinee_str,
as_ref_str,
body_str,
app,
})
}
pub struct SuggInfo<'a> {
pub needs_brackets: bool,
pub scrutinee_impl_copy: bool,
pub scrutinee_str: String,
pub as_ref_str: &'a str,
pub body_str: String,
pub app: Applicability,
}
// Checks whether the expression could be passed as a function, or whether a closure is needed.
// Returns the function to be passed to `map` if it exists.
fn can_pass_as_func<'tcx>(cx: &LateContext<'tcx>, binding: HirId, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
match expr.kind {
ExprKind::Call(func, [arg])
if path_to_local_id(arg, binding)
&& cx.typeck_results().expr_adjustments(arg).is_empty()
&& !type_is_unsafe_function(cx, cx.typeck_results().expr_ty(func).peel_refs()) =>
{
Some(func)
},
_ => None,
}
}
#[derive(Debug)]
pub(super) enum OptionPat<'a> {
Wild,
None,
Some {
// The pattern contained in the `Some` tuple.
pattern: &'a Pat<'a>,
// The number of references before the `Some` tuple.
// e.g. `&&Some(_)` has a ref count of 2.
ref_count: usize,
},
}
pub(super) struct SomeExpr<'tcx> {
pub expr: &'tcx Expr<'tcx>,
pub needs_unsafe_block: bool,
pub needs_negated: bool, // for `manual_filter` lint
}
impl<'tcx> SomeExpr<'tcx> {
pub fn new_no_negated(expr: &'tcx Expr<'tcx>, needs_unsafe_block: bool) -> Self {
Self {
expr,
needs_unsafe_block,
needs_negated: false,
}
}
pub fn to_snippet_with_context(
&self,
cx: &LateContext<'tcx>,
ctxt: SyntaxContext,
app: &mut Applicability,
) -> Sugg<'tcx> {
let sugg = Sugg::hir_with_context(cx, self.expr, ctxt, "..", app);
if self.needs_negated { !sugg } else { sugg }
}
}
// Try to parse into a recognized `Option` pattern.
// i.e. `_`, `None`, `Some(..)`, or a reference to any of those.
pub(super) fn try_parse_pattern<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
ctxt: SyntaxContext,
) -> Option<OptionPat<'tcx>> {
fn f<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
ref_count: usize,
ctxt: SyntaxContext,
) -> Option<OptionPat<'tcx>> {
match pat.kind {
PatKind::Wild => Some(OptionPat::Wild),
PatKind::Ref(pat, _) => f(cx, pat, ref_count + 1, ctxt),
PatKind::Path(ref qpath) if is_res_lang_ctor(cx, cx.qpath_res(qpath, pat.hir_id), OptionNone) => {
Some(OptionPat::None)
},
PatKind::TupleStruct(ref qpath, [pattern], _)
if is_res_lang_ctor(cx, cx.qpath_res(qpath, pat.hir_id), OptionSome) && pat.span.ctxt() == ctxt =>
{
Some(OptionPat::Some { pattern, ref_count })
},
_ => None,
}
}
f(cx, pat, 0, ctxt)
}
// Checks for an expression wrapped by the `Some` constructor. Returns the contained expression. // Checks for an expression wrapped by the `Some` constructor. Returns the contained expression.
fn get_some_expr<'tcx>( fn get_some_expr<'tcx>(
cx: &LateContext<'tcx>, cx: &LateContext<'tcx>,
@ -382,8 +114,3 @@ fn get_some_expr<'tcx>(
} }
get_some_expr_internal(cx, expr, false, ctxt) get_some_expr_internal(cx, expr, false, ctxt)
} }
// Checks for the `None` value.
fn is_none_expr(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
is_res_lang_ctor(cx, path_res(cx, peel_blocks(expr)), OptionNone)
}

278
clippy_lints/src/matches/manual_utils.rs Normal file
View file

@ -0,0 +1,278 @@
use crate::{map_unit_fn::OPTION_MAP_UNIT_FN, matches::MATCH_AS_REF};
use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
use clippy_utils::ty::{is_copy, is_type_diagnostic_item, peel_mid_ty_refs_is_mutable, type_is_unsafe_function};
use clippy_utils::{
can_move_expr_to_closure, is_else_clause, is_lint_allowed, is_res_lang_ctor, path_res, path_to_local_id,
peel_blocks, peel_hir_expr_refs, peel_hir_expr_while, sugg::Sugg, CaptureKind,
};
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_errors::Applicability;
use rustc_hir::LangItem::{OptionNone, OptionSome};
use rustc_hir::{def::Res, BindingAnnotation, Expr, ExprKind, HirId, Mutability, Pat, PatKind, Path, QPath};
use rustc_lint::LateContext;
use rustc_span::{sym, SyntaxContext};
#[expect(clippy::too_many_arguments)]
#[expect(clippy::too_many_lines)]
pub(super) fn check_with<'tcx, F>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
scrutinee: &'tcx Expr<'_>,
then_pat: &'tcx Pat<'_>,
then_body: &'tcx Expr<'_>,
else_pat: Option<&'tcx Pat<'_>>,
else_body: &'tcx Expr<'_>,
get_some_expr_fn: F,
) -> Option<SuggInfo<'tcx>>
where
F: Fn(&LateContext<'tcx>, &'tcx Pat<'_>, &'tcx Expr<'_>, SyntaxContext) -> Option<SomeExpr<'tcx>>,
{
let (scrutinee_ty, ty_ref_count, ty_mutability) =
peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(scrutinee));
if !(is_type_diagnostic_item(cx, scrutinee_ty, sym::Option)
&& is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::Option))
{
return None;
}
let expr_ctxt = expr.span.ctxt();
let (some_expr, some_pat, pat_ref_count, is_wild_none) = match (
try_parse_pattern(cx, then_pat, expr_ctxt),
else_pat.map_or(Some(OptionPat::Wild), |p| try_parse_pattern(cx, p, expr_ctxt)),
) {
(Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_body) => {
(else_body, pattern, ref_count, true)
},
(Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_body) => {
(else_body, pattern, ref_count, false)
},
(Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild)) if is_none_expr(cx, else_body) => {
(then_body, pattern, ref_count, true)
},
(Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None)) if is_none_expr(cx, else_body) => {
(then_body, pattern, ref_count, false)
},
_ => return None,
};
// Top level or patterns aren't allowed in closures.
if matches!(some_pat.kind, PatKind::Or(_)) {
return None;
}
let some_expr = match get_some_expr_fn(cx, some_pat, some_expr, expr_ctxt) {
Some(expr) => expr,
None => return None,
};
// These two lints will go back and forth with each other.
if cx.typeck_results().expr_ty(some_expr.expr) == cx.tcx.types.unit
&& !is_lint_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id)
{
return None;
}
// `map` won't perform any adjustments.
if !cx.typeck_results().expr_adjustments(some_expr.expr).is_empty() {
return None;
}
// Determine which binding mode to use.
let explicit_ref = some_pat.contains_explicit_ref_binding();
let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then_some(ty_mutability));
let as_ref_str = match binding_ref {
Some(Mutability::Mut) => ".as_mut()",
Some(Mutability::Not) => ".as_ref()",
None => "",
};
match can_move_expr_to_closure(cx, some_expr.expr) {
Some(captures) => {
// Check if captures the closure will need conflict with borrows made in the scrutinee.
// TODO: check all the references made in the scrutinee expression. This will require interacting
// with the borrow checker. Currently only `<local>[.<field>]*` is checked for.
if let Some(binding_ref_mutability) = binding_ref {
let e = peel_hir_expr_while(scrutinee, |e| match e.kind {
ExprKind::Field(e, _) | ExprKind::AddrOf(_, _, e) => Some(e),
_ => None,
});
if let ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(l), .. })) = e.kind {
match captures.get(l) {
Some(CaptureKind::Value | CaptureKind::Ref(Mutability::Mut)) => return None,
Some(CaptureKind::Ref(Mutability::Not)) if binding_ref_mutability == Mutability::Mut => {
return None;
},
Some(CaptureKind::Ref(Mutability::Not)) | None => (),
}
}
}
},
None => return None,
};
let mut app = Applicability::MachineApplicable;
// Remove address-of expressions from the scrutinee. Either `as_ref` will be called, or
// it's being passed by value.
let scrutinee = peel_hir_expr_refs(scrutinee).0;
let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app);
let scrutinee_str = if scrutinee.span.ctxt() == expr.span.ctxt() && scrutinee.precedence().order() < PREC_POSTFIX {
format!("({scrutinee_str})")
} else {
scrutinee_str.into()
};
let closure_expr_snip = some_expr.to_snippet_with_context(cx, expr_ctxt, &mut app);
let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind {
if_chain! {
if !some_expr.needs_unsafe_block;
if let Some(func) = can_pass_as_func(cx, id, some_expr.expr);
if func.span.ctxt() == some_expr.expr.span.ctxt();
then {
snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
} else {
if path_to_local_id(some_expr.expr, id)
&& !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id)
&& binding_ref.is_some()
{
return None;
}
// `ref` and `ref mut` annotations were handled earlier.
let annotation = if matches!(annotation, BindingAnnotation::MUT) {
"mut "
} else {
""
};
if some_expr.needs_unsafe_block {
format!("|{annotation}{some_binding}| unsafe {{ {closure_expr_snip} }}")
} else {
format!("|{annotation}{some_binding}| {closure_expr_snip}")
}
}
}
} else if !is_wild_none && explicit_ref.is_none() {
// TODO: handle explicit reference annotations.
let pat_snip = snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0;
if some_expr.needs_unsafe_block {
format!("|{pat_snip}| unsafe {{ {closure_expr_snip} }}")
} else {
format!("|{pat_snip}| {closure_expr_snip}")
}
} else {
// Refutable bindings and mixed reference annotations can't be handled by `map`.
return None;
};
// relies on the fact that Option<T>: Copy where T: copy
let scrutinee_impl_copy = is_copy(cx, scrutinee_ty);
Some(SuggInfo {
needs_brackets: else_pat.is_none() && is_else_clause(cx.tcx, expr),
scrutinee_impl_copy,
scrutinee_str,
as_ref_str,
body_str,
app,
})
}
pub struct SuggInfo<'a> {
pub needs_brackets: bool,
pub scrutinee_impl_copy: bool,
pub scrutinee_str: String,
pub as_ref_str: &'a str,
pub body_str: String,
pub app: Applicability,
}
// Checks whether the expression could be passed as a function, or whether a closure is needed.
// Returns the function to be passed to `map` if it exists.
fn can_pass_as_func<'tcx>(cx: &LateContext<'tcx>, binding: HirId, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
match expr.kind {
ExprKind::Call(func, [arg])
if path_to_local_id(arg, binding)
&& cx.typeck_results().expr_adjustments(arg).is_empty()
&& !type_is_unsafe_function(cx, cx.typeck_results().expr_ty(func).peel_refs()) =>
{
Some(func)
},
_ => None,
}
}
#[derive(Debug)]
pub(super) enum OptionPat<'a> {
Wild,
None,
Some {
// The pattern contained in the `Some` tuple.
pattern: &'a Pat<'a>,
// The number of references before the `Some` tuple.
// e.g. `&&Some(_)` has a ref count of 2.
ref_count: usize,
},
}
pub(super) struct SomeExpr<'tcx> {
pub expr: &'tcx Expr<'tcx>,
pub needs_unsafe_block: bool,
pub needs_negated: bool, // for `manual_filter` lint
}
impl<'tcx> SomeExpr<'tcx> {
pub fn new_no_negated(expr: &'tcx Expr<'tcx>, needs_unsafe_block: bool) -> Self {
Self {
expr,
needs_unsafe_block,
needs_negated: false,
}
}
pub fn to_snippet_with_context(
&self,
cx: &LateContext<'tcx>,
ctxt: SyntaxContext,
app: &mut Applicability,
) -> Sugg<'tcx> {
let sugg = Sugg::hir_with_context(cx, self.expr, ctxt, "..", app);
if self.needs_negated { !sugg } else { sugg }
}
}
// Try to parse into a recognized `Option` pattern.
// i.e. `_`, `None`, `Some(..)`, or a reference to any of those.
pub(super) fn try_parse_pattern<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
ctxt: SyntaxContext,
) -> Option<OptionPat<'tcx>> {
fn f<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
ref_count: usize,
ctxt: SyntaxContext,
) -> Option<OptionPat<'tcx>> {
match pat.kind {
PatKind::Wild => Some(OptionPat::Wild),
PatKind::Ref(pat, _) => f(cx, pat, ref_count + 1, ctxt),
PatKind::Path(ref qpath) if is_res_lang_ctor(cx, cx.qpath_res(qpath, pat.hir_id), OptionNone) => {
Some(OptionPat::None)
},
PatKind::TupleStruct(ref qpath, [pattern], _)
if is_res_lang_ctor(cx, cx.qpath_res(qpath, pat.hir_id), OptionSome) && pat.span.ctxt() == ctxt =>
{
Some(OptionPat::Some { pattern, ref_count })
},
_ => None,
}
}
f(cx, pat, 0, ctxt)
}
// Checks for the `None` value.
fn is_none_expr(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
is_res_lang_ctor(cx, path_res(cx, peel_blocks(expr)), OptionNone)
}

1
clippy_lints/src/matches/mod.rs
View file

@ -3,6 +3,7 @@ mod infallible_destructuring_match;
mod manual_filter; mod manual_filter;
mod manual_map; mod manual_map;
mod manual_unwrap_or; mod manual_unwrap_or;
mod manual_utils;
mod match_as_ref; mod match_as_ref;
mod match_bool; mod match_bool;
mod match_like_matches; mod match_like_matches;

2
clippy_utils/src/sugg.rs
View file

@ -112,7 +112,7 @@ impl<'a> Sugg<'a> {
if expr.span.ctxt() == ctxt { if expr.span.ctxt() == ctxt {
Self::hir_from_snippet(expr, |span| snippet(cx, span, default)) Self::hir_from_snippet(expr, |span| snippet(cx, span, default))
} else { } else {
let snip = snippet_with_context(cx, expr.span, ctxt, default, applicability).0; let (snip, _) = snippet_with_context(cx, expr.span, ctxt, default, applicability);
Sugg::NonParen(snip) Sugg::NonParen(snip)
} }
} }