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Lint on opt.as_ref().map(|x| &**x).

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This commit is contained in:
xiongmao86 2020-04-06 21:48:38 +08:00
parent c211cea3e9
commit 4f14826e09
5 changed files with 55 additions and 18 deletions
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4
clippy_lints/src/loops.rs
View file

@ -654,7 +654,7 @@ fn combine_branches(b1: NeverLoopResult, b2: NeverLoopResult) -> NeverLoopResult
fn never_loop_block(block: &Block<'_>, main_loop_id: HirId) -> NeverLoopResult {
let stmts = block.stmts.iter().map(stmt_to_expr);
let expr = once(block.expr.as_ref().map(|p| &**p));
let expr = once(block.expr.as_deref());
let mut iter = stmts.chain(expr).filter_map(|e| e);
never_loop_expr_seq(&mut iter, main_loop_id)
}
@ -662,7 +662,7 @@ fn never_loop_block(block: &Block<'_>, main_loop_id: HirId) -> NeverLoopResult {
fn stmt_to_expr<'tcx>(stmt: &Stmt<'tcx>) -> Option<&'tcx Expr<'tcx>> {
match stmt.kind {
StmtKind::Semi(ref e, ..) | StmtKind::Expr(ref e, ..) => Some(e),
StmtKind::Local(ref local) => local.init.as_ref().map(|p| &**p),
StmtKind::Local(ref local) => local.init.as_deref(),
_ => None,
}
}

49
clippy_lints/src/methods/mod.rs
View file

@ -3159,6 +3159,8 @@ fn lint_option_as_ref_deref<'a, 'tcx>(
map_args: &[hir::Expr<'_>],
is_mut: bool,
) {
let same_mutability = |m| (is_mut && m == &hir::Mutability::Mut) || (!is_mut && m == &hir::Mutability::Not);
let option_ty = cx.tables.expr_ty(&as_ref_args[0]);
if !match_type(cx, option_ty, &paths::OPTION) {
return;
@ -3181,23 +3183,40 @@ fn lint_option_as_ref_deref<'a, 'tcx>(
hir::ExprKind::Closure(_, _, body_id, _, _) => {
let closure_body = cx.tcx.hir().body(body_id);
let closure_expr = remove_blocks(&closure_body.value);
if_chain! {
if let hir::ExprKind::MethodCall(_, _, args) = &closure_expr.kind;
if args.len() == 1;
if let hir::ExprKind::Path(qpath) = &args[0].kind;
if let hir::def::Res::Local(local_id) = cx.tables.qpath_res(qpath, args[0].hir_id);
if closure_body.params[0].pat.hir_id == local_id;
let adj = cx.tables.expr_adjustments(&args[0]).iter().map(|x| &x.kind).collect::<Box<[_]>>();
if let [ty::adjustment::Adjust::Deref(None), ty::adjustment::Adjust::Borrow(_)] = *adj;
then {
let method_did = cx.tables.type_dependent_def_id(closure_expr.hir_id).unwrap();
deref_aliases.iter().any(|path| match_def_path(cx, method_did, path))
} else {
false
}
match &closure_expr.kind {
hir::ExprKind::MethodCall(_, _, args) => {
if_chain! {
if args.len() == 1;
if let hir::ExprKind::Path(qpath) = &args[0].kind;
if let hir::def::Res::Local(local_id) = cx.tables.qpath_res(qpath, args[0].hir_id);
if closure_body.params[0].pat.hir_id == local_id;
let adj = cx.tables.expr_adjustments(&args[0]).iter().map(|x| &x.kind).collect::<Box<[_]>>();
if let [ty::adjustment::Adjust::Deref(None), ty::adjustment::Adjust::Borrow(_)] = *adj;
then {
let method_did = cx.tables.type_dependent_def_id(closure_expr.hir_id).unwrap();
deref_aliases.iter().any(|path| match_def_path(cx, method_did, path))
} else {
false
}
}
},
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, m, ref inner) if same_mutability(m) => {
if_chain! {
if let hir::ExprKind::Unary(hir::UnOp::UnDeref, ref inner1) = inner.kind;
if let hir::ExprKind::Unary(hir::UnOp::UnDeref, ref inner2) = inner1.kind;
if let hir::ExprKind::Path(ref qpath) = inner2.kind;
if let hir::def::Res::Local(local_id) = cx.tables.qpath_res(qpath, inner2.hir_id);
then {
closure_body.params[0].pat.hir_id == local_id
} else {
false
}
}
},
_ => false,
}
},
_ => false,
};

3
tests/ui/option_as_ref_deref.fixed
View file

@ -35,4 +35,7 @@ fn main() {
let _ = Some(1_usize).as_ref().map(|x| vc[*x].as_str()); // should not be linted
let _: Option<&str> = Some(&String::new()).as_ref().map(|x| x.as_str()); // should not be linted
let _ = opt.as_deref();
let _ = opt.as_deref_mut();
}

3
tests/ui/option_as_ref_deref.rs
View file

@ -38,4 +38,7 @@ fn main() {
let _ = Some(1_usize).as_ref().map(|x| vc[*x].as_str()); // should not be linted
let _: Option<&str> = Some(&String::new()).as_ref().map(|x| x.as_str()); // should not be linted
let _ = opt.as_ref().map(|x| &**x);
let _ = opt.as_mut().map(|x| &mut **x);
}

14
tests/ui/option_as_ref_deref.stderr
View file

@ -88,5 +88,17 @@ error: called `.as_mut().map(DerefMut::deref_mut)` (or with one of deref aliases
LL | let _ = opt.clone().as_mut().map(|x| x.deref_mut()).map(|x| x.len());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using as_deref_mut instead: `opt.clone().as_deref_mut()`
error: aborting due to 14 previous errors
error: called `.as_ref().map(Deref::deref)` (or with one of deref aliases) on an Option value. This can be done more directly by calling `opt.as_deref()` instead
--> $DIR/option_as_ref_deref.rs:42:13
|
LL | let _ = opt.as_ref().map(|x| &**x);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using as_deref instead: `opt.as_deref()`
error: called `.as_mut().map(DerefMut::deref_mut)` (or with one of deref aliases) on an Option value. This can be done more directly by calling `opt.as_deref_mut()` instead
--> $DIR/option_as_ref_deref.rs:43:13
|
LL | let _ = opt.as_mut().map(|x| &mut **x);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try using as_deref_mut instead: `opt.as_deref_mut()`
error: aborting due to 16 previous errors