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rust/tests/ui/pattern
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Chris Denton 5d2375f789
Rollup merge of #139042 - compiler-errors:do-not-optimize-switchint, r=saethlin 
Do not remove trivial `SwitchInt` in analysis MIR

This PR ensures that we don't prematurely remove trivial `SwitchInt` terminators which affects both the borrow-checking and runtime semantics (i.e. UB) of the code. Previously the `SimplifyCfg` optimization was removing `SwitchInt` terminators when they was "trivial", i.e. when all arms branched to the same basic block, even if that `SwitchInt` terminator had the side-effect of reading an operand which (for example) may not be initialized or may point to an invalid place in memory.

This behavior is unlike all other optimizations, which are only applied after "analysis" (i.e. borrow-checking) is finished, and which Miri disables to make sure the compiler doesn't silently remove UB.

Fixing this code "breaks" (i.e. unmasks) code that used to borrow-check but no longer does, like:

```rust
fn foo() {
    let x;
    let (0 | _) = x;
}
```

This match expression should perform a read because `_` does not shadow the `0` literal pattern, and the compiler should have to read the match scrutinee to compare it to 0. I've checked that this behavior does not actually manifest in practice via a crater run which came back clean: https://github.com/rust-lang/rust/pull/139042#issuecomment-2767436367

As a side-note, it may be tempting to suggest that this is actually a good thing or that we should preserve this behavior. If we wanted to make this work (i.e. trivially optimize out reads from matches that are redundant like `0 | _`), then we should be enabling this behavior *after* fixing this. However, I think it's kinda unprincipled, and for example other variations of the code don't even work today, e.g.:

```rust
fn foo() {
    let x;
    let (0.. | _) = x;
}
```
2025-04-19 19:30:46 +00:00
..
auxiliary Move existing rfc3627 tests to a dedicated folder 2024-09-24 13:45:58 +02:00
bindings-after-at Auto merge of #139949 - matthiaskrgr:rollup-pxc5tsx, r=matthiaskrgr 2025-04-17 11:21:54 +00:00
deref-patterns Make cow_of_cow test a teeny bit more explicit 2025-04-16 15:42:13 -07:00
move-ref-patterns Better span for "make binding mutable" suggestion 2024-07-04 02:02:21 +00:00
rfc-3627-match-ergonomics-2024 UI tests: add missing diagnostic kinds where possible 2025-04-08 23:06:31 +03:00
rfc-3637-guard-patterns Address review comments 2024-12-07 13:37:35 +01:00
usefulness UI tests: add missing diagnostic kinds where possible 2025-04-08 23:06:31 +03:00
at-in-struct-patterns.rs Parser: better error messages for @ in struct patterns 2024-09-23 02:12:53 +03:00
at-in-struct-patterns.stderr Parser: better error messages for @ in struct patterns 2024-09-23 02:12:53 +03:00
box-pattern-type-mismatch.rs Replace some Option<Diag> with Result<(), Diag> 2024-06-13 06:16:12 +00:00
box-pattern-type-mismatch.stderr Replace some Option<Diag> with Result<(), Diag> 2024-06-13 06:16:12 +00:00
by-move-pattern-binding.rs Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
by-move-pattern-binding.stderr Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
byte-string-inference.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
check-struct-pat-fields-stability-issue-138319.rs Pass precise HirId when calling check_stability 2025-03-14 14:51:58 +08:00
check-struct-pat-fields-stability-issue-138319.stderr Pass precise HirId when calling check_stability 2025-03-14 14:51:58 +08:00
complexity_limit.rs Rename pattern_complexity attr as pattern_complexity_limit. 2025-02-17 09:30:40 +11:00
complexity_limit.stderr Add and update tests to use pattern_complexity 2024-03-03 13:10:15 +01:00
fn-in-pat.rs Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
fn-in-pat.stderr Update tests for new TRPL chapter order 2024-11-23 08:57:25 -07:00
for-loop-bad-item.rs
for-loop-bad-item.stderr
ignore-all-the-things.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
inc-range-pat.rs Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
incorrect-placement-of-pattern-modifiers.fixed [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
incorrect-placement-of-pattern-modifiers.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
incorrect-placement-of-pattern-modifiers.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
integer-range-binding.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-6449.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-8351-1.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-8351-2.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-10392.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-11577.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-12582.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-14221.rs
issue-14221.stderr Reword the "unreachable pattern" explanations 2024-08-19 21:39:57 +02:00
issue-15080.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-17718-patterns.rs
issue-17718-patterns.stderr
issue-22546.rs Revert "Rollup merge of #126618 - mu001999-contrib:dead/enhance, r=pnkfelix" 2024-08-03 07:57:31 -04:00
issue-22546.stderr Revert "Rollup merge of #126618 - mu001999-contrib:dead/enhance, r=pnkfelix" 2024-08-03 07:57:31 -04:00
issue-27320.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-28992-empty.rs Move some tests 2024-02-09 15:43:08 -03:00
issue-28992-empty.stderr Move some tests 2024-02-09 15:43:08 -03:00
issue-52240.rs
issue-52240.stderr
issue-66270-pat-struct-parser-recovery.rs
issue-66270-pat-struct-parser-recovery.stderr
issue-67037-pat-tup-scrut-ty-diff-less-fields.rs
issue-67037-pat-tup-scrut-ty-diff-less-fields.stderr
issue-67776-match-same-name-enum-variant-refs.rs
issue-67776-match-same-name-enum-variant-refs.stderr
issue-72565.rs
issue-72565.stderr Specify type kind of constant that can't be used in patterns 2024-12-04 20:29:36 +00:00
issue-72574-1.rs
issue-72574-1.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
issue-72574-2.rs
issue-72574-2.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
issue-74539.rs
issue-74539.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
issue-74702.rs
issue-74702.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
issue-74954.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-80186-mut-binding-help-suggestion.rs
issue-80186-mut-binding-help-suggestion.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
issue-88074-pat-range-type-inference-err.rs
issue-88074-pat-range-type-inference-err.stderr
issue-88074-pat-range-type-inference.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-92074-macro-ice.rs
issue-92074-macro-ice.stderr Change wording 2024-04-29 14:53:38 +02:00
issue-94866.rs
issue-94866.stderr
issue-95878.rs
issue-95878.stderr
issue-106552.rs
issue-106552.stderr Update tests for new TRPL chapter order 2024-11-23 08:57:25 -07:00
issue-106862.fixed [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-106862.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
issue-106862.stderr
issue-110508.rs Handle all PatExprs in dead code analysis 2025-01-29 15:45:13 +00:00
issue-115599.rs Add additional context for non-sructural type constant used in pattern 2024-12-04 20:29:36 +00:00
issue-115599.stderr Add additional context for non-sructural type constant used in pattern 2024-12-04 20:29:36 +00:00
issue-117626.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
missing_lifetime.rs Avoid follow-up errors on erroneous patterns 2024-06-13 06:14:32 +00:00
missing_lifetime.stderr Avoid follow-up errors on erroneous patterns 2024-06-13 06:14:32 +00:00
mut-ref-mut-2021.rs Feature gate 2024-03-27 11:20:28 -04:00
mut-ref-mut-2021.stderr Better span for "make binding mutable" suggestion 2024-07-04 02:02:21 +00:00
mut_preserve_binding_mode_2021.rs Gate implicit mutable by-reference bindings behind mut ref 2024-05-15 16:55:54 -04:00
mut_preserve_binding_mode_2021.stderr Fix tests 2024-04-15 23:27:22 -04:00
mut_preserve_binding_mode_2024.rs Stabilize the 2024 edition 2024-11-22 11:12:15 -08:00
no-match-tuple-variant-self-ctor.rs Validate that we're only matching on unit struct for path pattern 2024-03-22 20:53:42 -04:00
no-match-tuple-variant-self-ctor.struct_.stderr Validate that we're only matching on unit struct for path pattern 2024-03-22 20:53:42 -04:00
no-match-tuple-variant-self-ctor.tuple.stderr Validate that we're only matching on unit struct for path pattern 2024-03-22 20:53:42 -04:00
no-patterns-in-args-2.rs Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
no-patterns-in-args-2.stderr Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
no-patterns-in-args.rs Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
no-patterns-in-args.stderr Move 100 entries from tests/ui into subdirs 2024-05-20 19:55:59 -07:00
non-constant-in-const-path.rs
non-constant-in-const-path.stderr Tweak output of some const pattern errors 2024-12-04 20:29:36 +00:00
non-structural-match-types-cycle-err.rs borrowck typeck children together with their parent 2025-04-08 00:34:40 +02:00
non-structural-match-types-cycle-err.stderr borrowck typeck children together with their parent 2025-04-08 00:34:40 +02:00
non-structural-match-types.rs borrowck typeck children together with their parent 2025-04-08 00:34:40 +02:00
non-structural-match-types.stderr borrowck typeck children together with their parent 2025-04-08 00:34:40 +02:00
overflowing-literals.rs Uniformly handle HIR literals in visitors and lints 2025-02-05 11:28:24 +00:00
overflowing-literals.stderr Uniformly handle HIR literals in visitors and lints 2025-02-05 11:28:24 +00:00
pat-shadow-in-nested-binding.rs
pat-shadow-in-nested-binding.stderr
pat-struct-field-expr-has-type.rs
pat-struct-field-expr-has-type.stderr
pat-tuple-bad-type.rs
pat-tuple-bad-type.stderr
pat-tuple-field-count-cross.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
pat-tuple-field-count-cross.stderr Trim suggestion parts to the subset that is purely additive 2025-02-14 00:44:10 -08:00
pat-tuple-overfield.rs
pat-tuple-overfield.stderr Trim suggestion parts to the subset that is purely additive 2025-02-14 00:44:10 -08:00
pat-tuple-underfield.rs
pat-tuple-underfield.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
pat-type-err-formal-param.rs
pat-type-err-formal-param.stderr
pat-type-err-let-stmt.rs
pat-type-err-let-stmt.stderr
patkind-litrange-no-expr.rs Rename PatKind::Lit to Expr 2025-01-08 07:34:59 +00:00
patkind-litrange-no-expr.stderr
patkind-ref-binding-issue-114896.fixed UI tests: add missing diagnostic kinds where possible 2025-04-08 23:06:31 +03:00
patkind-ref-binding-issue-114896.rs UI tests: add missing diagnostic kinds where possible 2025-04-08 23:06:31 +03:00
patkind-ref-binding-issue-114896.stderr Trim suggestion parts to the subset that is purely additive 2025-02-14 00:44:10 -08:00
patkind-ref-binding-issue-122415.fixed Fix incorrect mutable suggestion information for binding in ref pattern. 2024-03-19 12:28:23 +08:00
patkind-ref-binding-issue-122415.rs Fix incorrect mutable suggestion information for binding in ref pattern. 2024-03-19 12:28:23 +08:00
patkind-ref-binding-issue-122415.stderr Trim suggestion parts to the subset that is purely additive 2025-02-14 00:44:10 -08:00
pattern-bad-ref-box-order.fixed [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
pattern-bad-ref-box-order.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
pattern-bad-ref-box-order.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
pattern-binding-disambiguation.rs Continue to borrowck even if there were previous errors 2024-02-08 08:10:43 +00:00
pattern-binding-disambiguation.stderr Update tests for new TRPL chapter order 2024-11-23 08:57:25 -07:00
pattern-error-continue.rs
pattern-error-continue.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
pattern-ident-path-generics.rs
pattern-ident-path-generics.stderr
pattern-tyvar-2.rs
pattern-tyvar-2.stderr Change E0369 diagnostic give note information for foreign items. 2024-06-25 10:00:30 +08:00
pattern-tyvar.rs
pattern-tyvar.stderr
patterns-dont-match-nt-statement.rs Don't make pattern nonterminals match statement nonterminals 2024-08-26 18:30:15 -04:00
range-pattern-meant-to-be-slice-rest-pattern.rs Stabilize exclusive_range 2024-05-02 19:42:31 -04:00
range-pattern-meant-to-be-slice-rest-pattern.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
rest-pat-semantic-disallowed.rs
rest-pat-semantic-disallowed.stderr
rest-pat-syntactic.rs Use cfg(false) in UI tests 2025-04-03 21:41:58 +00:00
rest-pat-syntactic.stderr
self-ctor-133272.rs Re-delay a resolve bug 2024-11-21 18:40:36 +08:00
self-ctor-133272.stderr Re-delay a resolve bug 2024-11-21 18:40:36 +08:00
size-and-align.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
skipped-ref-pats-issue-125058.rs Stabilize the 2024 edition 2024-11-22 11:12:15 -08:00
skipped-ref-pats-issue-125058.stderr Stabilize the 2024 edition 2024-11-22 11:12:15 -08:00
slice-array-infer.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
slice-pattern-refutable.rs
slice-pattern-refutable.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
slice-patterns-ambiguity.rs
slice-patterns-ambiguity.stderr Show diff suggestion format on verbose replacement 2025-02-10 20:21:39 +00:00
slice-patterns-irrefutable.rs
slice-patterns-irrefutable.stderr
slice-patterns-nested.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
struct-parser-recovery-issue-126344.rs report pat no field error no recoverd struct variant 2024-07-11 00:18:47 +08:00
struct-parser-recovery-issue-126344.stderr report pat no field error no recoverd struct variant 2024-07-11 00:18:47 +08:00
struct-pattern-on-non-struct-resolve-error.rs modify test to side-step platform-dependent stderr output 2025-01-08 00:13:43 +00:00
struct-pattern-on-non-struct-resolve-error.stderr modify test to side-step platform-dependent stderr output 2025-01-08 00:13:43 +00:00
struct-pattern-with-missing-fields-resolve-error.rs Add check for missing fields in enum variant pattern 2025-01-08 00:10:16 +00:00
struct-pattern-with-missing-fields-resolve-error.stderr Add check for missing fields in enum variant pattern 2025-01-08 00:10:16 +00:00
suggest-adding-appropriate-missing-pattern-excluding-comments.fixed [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
suggest-adding-appropriate-missing-pattern-excluding-comments.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
suggest-adding-appropriate-missing-pattern-excluding-comments.stderr
type_mismatch.rs Avoid follow-up errors on erroneous patterns 2024-06-13 06:14:32 +00:00
type_mismatch.stderr Avoid follow-up errors on erroneous patterns 2024-06-13 06:14:32 +00:00
uninit-trivial.rs Do not optimize out SwitchInt before borrowck, or if Zmir-preserve-ub 2025-04-08 21:05:20 +00:00
uninit-trivial.stderr Do not optimize out SwitchInt before borrowck, or if Zmir-preserve-ub 2025-04-08 21:05:20 +00:00