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Suggest the correct variable name for manual_let_else

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koka 2023-02-01 19:17:39 +09:00
parent 75d76806c1
commit a408e76098
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3 changed files with 52 additions and 43 deletions
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59
clippy_lints/src/manual_let_else.rs
View file

@ -68,29 +68,21 @@ 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) &&
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) => {
@ -120,15 +112,23 @@ 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,
@ -137,12 +137,11 @@ 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);
@ -151,10 +150,20 @@ 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})")
},
PatKind::TupleStruct(ref w, ..) => {
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);

32
tests/ui/manual_let_else.stderr
View file

@ -2,7 +2,7 @@ error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:18:5
|
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`
@ -18,7 +18,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + return;
LL + };
|
@ -48,19 +48,19 @@ error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:38:9
|
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
|
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
|
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
@ -74,7 +74,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + std::process::abort()
LL + };
|
@ -91,7 +91,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + if true { return } else { panic!() }
LL + };
|
@ -109,7 +109,7 @@ LL | | };
|
help: consider writing
|
LL ~ let Some(v_some) = g() else {
LL ~ let Some(v) = g() else {
LL + if true {}
LL + panic!();
LL + };
@ -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!(),
@ -141,7 +141,7 @@ error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:80:5
|
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
@ -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 + }
@ -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");
@ -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(_)) => {
@ -226,7 +226,7 @@ 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 + };
|
@ -252,7 +252,7 @@ error: this could be rewritten as `let...else`
--> $DIR/manual_let_else.rs:134:13
|
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
@ -266,7 +266,7 @@ 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

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