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Auto merge of #10175 - koka831:fix/10171, r=giraffate

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Use original variable name in the suggestion

Fix https://github.com/rust-lang/rust-clippy/issues/10171

---

changelog: Sugg: [`manual_let_else`]: Now suggest the correct variable name
[#10175](https://github.com/rust-lang/rust-clippy/pull/10175)
<!-- changelog_checked -->
This commit is contained in:
bors 2023-05-18 01:21:27 +00:00
commit 7e18451633
4 changed files with 100 additions and 62 deletions
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61
clippy_lints/src/manual_let_else.rs
View file

@ -38,7 +38,6 @@ declare_clippy_lint! {
/// Could be written:
///
/// ```rust
/// # #![feature(let_else)]
/// # fn main () {
/// # let w = Some(0);
/// let Some(v) = w else { return };
@ -69,29 +68,23 @@ impl_lint_pass!(ManualLetElse => [MANUAL_LET_ELSE]);
impl<'tcx> LateLintPass<'tcx> for ManualLetElse {
fn check_stmt(&mut self, cx: &LateContext<'_>, stmt: &'tcx Stmt<'tcx>) {
let if_let_or_match = if_chain! {
if self.msrv.meets(msrvs::LET_ELSE);
if !in_external_macro(cx.sess(), stmt.span);
if let StmtKind::Local(local) = stmt.kind;
if let Some(init) = local.init;
if local.els.is_none();
if local.ty.is_none();
if init.span.ctxt() == stmt.span.ctxt();
if let Some(if_let_or_match) = IfLetOrMatch::parse(cx, init);
then {
if_let_or_match
} else {
return;
}
};
if !self.msrv.meets(msrvs::LET_ELSE) || in_external_macro(cx.sess(), stmt.span) {
return;
}
if let StmtKind::Local(local) = stmt.kind &&
let Some(init) = local.init &&
local.els.is_none() &&
local.ty.is_none() &&
init.span.ctxt() == stmt.span.ctxt() &&
let Some(if_let_or_match) = IfLetOrMatch::parse(cx, init) {
match if_let_or_match {
IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else) => if_chain! {
if expr_is_simple_identity(let_pat, if_then);
if let Some(if_else) = if_else;
if expr_diverges(cx, if_else);
then {
emit_manual_let_else(cx, stmt.span, if_let_expr, let_pat, if_else);
emit_manual_let_else(cx, stmt.span, if_let_expr, local.pat, let_pat, if_else);
}
},
IfLetOrMatch::Match(match_expr, arms, source) => {
@ -128,15 +121,23 @@ impl<'tcx> LateLintPass<'tcx> for ManualLetElse {
return;
}
emit_manual_let_else(cx, stmt.span, match_expr, pat_arm.pat, diverging_arm.body);
emit_manual_let_else(cx, stmt.span, match_expr, local.pat, pat_arm.pat, diverging_arm.body);
},
}
};
}
extract_msrv_attr!(LateContext);
}
fn emit_manual_let_else(cx: &LateContext<'_>, span: Span, expr: &Expr<'_>, pat: &Pat<'_>, else_body: &Expr<'_>) {
fn emit_manual_let_else(
cx: &LateContext<'_>,
span: Span,
expr: &Expr<'_>,
local: &Pat<'_>,
pat: &Pat<'_>,
else_body: &Expr<'_>,
) {
span_lint_and_then(
cx,
MANUAL_LET_ELSE,
@ -145,12 +146,11 @@ fn emit_manual_let_else(cx: &LateContext<'_>, span: Span, expr: &Expr<'_>, pat:
|diag| {
// This is far from perfect, for example there needs to be:
// * mut additions for the bindings
// * renamings of the bindings
// * renamings of the bindings for `PatKind::Or`
// * unused binding collision detection with existing ones
// * putting patterns with at the top level | inside ()
// for this to be machine applicable.
let mut app = Applicability::HasPlaceholders;
let (sn_pat, _) = snippet_with_context(cx, pat.span, span.ctxt(), "", &mut app);
let (sn_expr, _) = snippet_with_context(cx, expr.span, span.ctxt(), "", &mut app);
let (sn_else, _) = snippet_with_context(cx, else_body.span, span.ctxt(), "", &mut app);
@ -159,10 +159,21 @@ fn emit_manual_let_else(cx: &LateContext<'_>, span: Span, expr: &Expr<'_>, pat:
} else {
format!("{{ {sn_else} }}")
};
let sn_bl = if matches!(pat.kind, PatKind::Or(..)) {
format!("({sn_pat})")
} else {
sn_pat.into_owned()
let sn_bl = match pat.kind {
PatKind::Or(..) => {
let (sn_pat, _) = snippet_with_context(cx, pat.span, span.ctxt(), "", &mut app);
format!("({sn_pat})")
},
// Replace the variable name iff `TupleStruct` has one argument like `Variant(v)`.
PatKind::TupleStruct(ref w, args, ..) if args.len() == 1 => {
let sn_wrapper = cx.sess().source_map().span_to_snippet(w.span()).unwrap_or_default();
let (sn_inner, _) = snippet_with_context(cx, local.span, span.ctxt(), "", &mut app);
format!("{sn_wrapper}({sn_inner})")
},
_ => {
let (sn_pat, _) = snippet_with_context(cx, pat.span, span.ctxt(), "", &mut app);
sn_pat.into_owned()
},
};
let sugg = format!("let {sn_bl} = {sn_expr} else {else_bl};");
diag.span_suggestion(span, "consider writing", sugg, app);

15
tests/ui/manual_let_else.rs
View file

@ -8,6 +8,12 @@
)]
#![warn(clippy::manual_let_else)]
enum Variant {
A(usize, usize),
B(usize),
C,
}
fn g() -> Option<()> {
None
}
@ -135,6 +141,15 @@ fn fire() {
};
}
create_binding_if_some!(w, g());
fn e() -> Variant {
Variant::A(0, 0)
}
// Should not be renamed
let v = if let Variant::A(a, 0) = e() { a } else { return };
// Should be renamed
let v = if let Variant::B(b) = e() { b } else { return };
}
fn not_fire() {

82
tests/ui/manual_let_else.stderr
View file

@ -1,13 +1,13 @@
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:18:5
--> $DIR/manual_let_else.rs:24:5
|
LL | let v = if let Some(v_some) = g() { v_some } else { return };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v_some) = g() else { return };`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { return };`
|
= note: `-D clippy::manual-let-else` implied by `-D warnings`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:19:5
--> $DIR/manual_let_else.rs:25:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -18,13 +18,13 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + return;
LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:25:5
--> $DIR/manual_let_else.rs:31:5
|
LL | / let v = if let Some(v) = g() {
LL | | // Blocks around the identity should have no impact
@ -45,25 +45,25 @@ LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:38:9
--> $DIR/manual_let_else.rs:44:9
|
LL | let v = if let Some(v_some) = g() { v_some } else { continue };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v_some) = g() else { continue };`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { continue };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:39:9
--> $DIR/manual_let_else.rs:45:9
|
LL | let v = if let Some(v_some) = g() { v_some } else { break };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v_some) = g() else { break };`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { break };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:43:5
--> $DIR/manual_let_else.rs:49:5
|
LL | let v = if let Some(v_some) = g() { v_some } else { panic!() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v_some) = g() else { panic!() };`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { panic!() };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:46:5
--> $DIR/manual_let_else.rs:52:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -74,13 +74,13 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + std::process::abort()
LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:53:5
--> $DIR/manual_let_else.rs:59:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -91,13 +91,13 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + if true { return } else { panic!() }
LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:60:5
--> $DIR/manual_let_else.rs:66:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -109,14 +109,14 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + if true {}
LL + panic!();
LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:70:5
--> $DIR/manual_let_else.rs:76:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -129,7 +129,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + match () {
LL + _ if panic!() => {},
LL + _ => panic!(),
@ -138,13 +138,13 @@ LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:80:5
--> $DIR/manual_let_else.rs:86:5
|
LL | let v = if let Some(v_some) = g() { v_some } else { if panic!() {} };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v_some) = g() else { if panic!() {} };`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { if panic!() {} };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:83:5
--> $DIR/manual_let_else.rs:89:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -157,7 +157,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + match panic!() {
LL + _ => {},
LL + }
@ -165,7 +165,7 @@ LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:92:5
--> $DIR/manual_let_else.rs:98:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -178,7 +178,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else { if true {
LL ~ let Some(v) = g() else { if true {
LL + return;
LL + } else {
LL + panic!("diverge");
@ -186,7 +186,7 @@ LL + } };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:101:5
--> $DIR/manual_let_else.rs:107:5
|
LL | / let v = if let Some(v_some) = g() {
LL | | v_some
@ -199,7 +199,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + match (g(), g()) {
LL + (Some(_), None) => return,
LL + (None, Some(_)) => {
@ -215,7 +215,7 @@ LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:118:5
--> $DIR/manual_let_else.rs:124:5
|
LL | / let (v, w) = if let Some(v_some) = g().map(|v| (v, 42)) {
LL | | v_some
@ -226,13 +226,13 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g().map(|v| (v, 42)) else {
LL ~ let Some((v, w)) = g().map(|v| (v, 42)) else {
LL + return;
LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:125:5
--> $DIR/manual_let_else.rs:131:5
|
LL | / let v = if let (Some(v_some), w_some) = (g(), 0) {
LL | | (w_some, v_some)
@ -249,10 +249,10 @@ LL + };
|
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:134:13
--> $DIR/manual_let_else.rs:140:13
|
LL | let $n = if let Some(v) = $e { v } else { return };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { return };`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some($n) = g() else { return };`
...
LL | create_binding_if_some!(w, g());
| ------------------------------- in this macro invocation
@ -260,13 +260,25 @@ LL | create_binding_if_some!(w, g());
= note: this error originates in the macro `create_binding_if_some` (in Nightly builds, run with -Z macro-backtrace for more info)
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:247:5
--> $DIR/manual_let_else.rs:150:5
|
LL | let v = if let Variant::A(a, 0) = e() { a } else { return };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Variant::A(a, 0) = e() else { return };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:152:5
|
LL | let v = if let Variant::B(b) = e() { b } else { return };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Variant::B(v) = e() else { return };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:262:5
|
LL | / let _ = match ff {
LL | | Some(value) => value,
LL | | _ => macro_call!(),
LL | | };
| |______^ help: consider writing: `let Some(value) = ff else { macro_call!() };`
| |______^ help: consider writing: `let Some(_) = ff else { macro_call!() };`
error: aborting due to 18 previous errors
error: aborting due to 20 previous errors

4
tests/ui/manual_let_else_match.stderr
View file

@ -5,7 +5,7 @@ LL | / let v = match g() {
LL | | Some(v_some) => v_some,
LL | | None => return,
LL | | };
| |______^ help: consider writing: `let Some(v_some) = g() else { return };`
| |______^ help: consider writing: `let Some(v) = g() else { return };`
|
= note: `-D clippy::manual-let-else` implied by `-D warnings`
@ -16,7 +16,7 @@ LL | / let v = match g() {
LL | | Some(v_some) => v_some,
LL | | _ => return,
LL | | };
| |______^ help: consider writing: `let Some(v_some) = g() else { return };`
| |______^ help: consider writing: `let Some(v) = g() else { return };`
error: this could be rewritten as `let...else`
--> $DIR/manual_let_else_match.rs:44:9