break out scopes when let-else fails to match · rust-lang/rust@9b56640 (original) (raw)

`@@ -2282,49 +2282,55 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {

2282

`initializer_span: Span,

2283

`else_block: &Block,

2284

`visibility_scope: Option,

2285

remainder_scope: region::Scope,

2285

2286

`remainder_span: Span,

2286

2287

`pattern: &Pat<'tcx>,

2287

2288

`) -> BlockAnd<()> {

2288

let scrutinee = unpack!(block = self.lower_scrutinee(block, init, initializer_span));

2289

let pat = Pat { ty: init.ty, span: else_block.span, kind: Box::new(PatKind::Wild) };

2290

let mut wildcard = Candidate::new(scrutinee.clone(), &pat, false);

2291

self.declare_bindings(

2292

visibility_scope,

2293

remainder_span,

2294

pattern,

2295

ArmHasGuard(false),

2296

Some((None, initializer_span)),

2297

);

2298

let mut candidate = Candidate::new(scrutinee.clone(), pattern, false);

2299

let fake_borrow_temps = self.lower_match_tree(

2300

block,

2301

initializer_span,

2302

pattern.span,

2303

false,

2304

&mut [&mut candidate, &mut wildcard],

2305

);

2306

// This block is for the matching case

2307

let matching = self.bind_pattern(

2308

self.source_info(pattern.span),

2309

candidate,

2310

None,

2311

&fake_borrow_temps,

2312

initializer_span,

2313

None,

2314

None,

2315

None,

2316

);

2317

// This block is for the failure case

2318

let failure = self.bind_pattern(

2319

self.source_info(else_block.span),

2320

wildcard,

2321

None,

2322

&fake_borrow_temps,

2323

initializer_span,

2324

None,

2325

None,

2326

None,

2327

);

2289

let (matching, failure) = self.in_if_then_scope(remainder_scope, |this| {

2290

let scrutinee = unpack!(block = this.lower_scrutinee(block, init, initializer_span));

2291

let pat = Pat { ty: init.ty, span: else_block.span, kind: Box::new(PatKind::Wild) };

2292

let mut wildcard = Candidate::new(scrutinee.clone(), &pat, false);

2293

this.declare_bindings(

2294

visibility_scope,

2295

remainder_span,

2296

pattern,

2297

ArmHasGuard(false),

2298

Some((None, initializer_span)),

2299

);

2300

let mut candidate = Candidate::new(scrutinee.clone(), pattern, false);

2301

let fake_borrow_temps = this.lower_match_tree(

2302

block,

2303

initializer_span,

2304

pattern.span,

2305

false,

2306

&mut [&mut candidate, &mut wildcard],

2307

);

2308

// This block is for the matching case

2309

let matching = this.bind_pattern(

2310

this.source_info(pattern.span),

2311

candidate,

2312

None,

2313

&fake_borrow_temps,

2314

initializer_span,

2315

None,

2316

None,

2317

None,

2318

);

2319

// This block is for the failure case

2320

let failure = this.bind_pattern(

2321

this.source_info(else_block.span),

2322

wildcard,

2323

None,

2324

&fake_borrow_temps,

2325

initializer_span,

2326

None,

2327

None,

2328

None,

2329

);

2330

this.break_for_else(failure, remainder_scope, this.source_info(initializer_span));

2331

matching.unit()

2332

});

2333

+

2328

2334

`// This place is not really used because this destination place

2329

2335

`// should never be used to take values at the end of the failure

2330

2336

`// block.