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add note for non-exhaustive matches with guards #113019

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Jun 28, 2023
Merged

add note for non-exhaustive matches with guards #113019

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fbd1e02
add note for non-exhaustive matches with guards
ericmarkmartin Jun 22, 2023
e79b179
add comment back
ericmarkmartin Jun 28, 2023
2017a17
use translatable subdiagnostic
ericmarkmartin Jun 28, 2023
96bd056
remove cruft
ericmarkmartin Jun 28, 2023
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3 changes: 3 additions & 0 deletions compiler/rustc_mir_build/messages.ftl
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Original file line number Diff line number Diff line change
Expand Up @@ -214,6 +214,9 @@ mir_build_mutation_of_layout_constrained_field_requires_unsafe_unsafe_op_in_unsa

mir_build_non_const_path = runtime values cannot be referenced in patterns

mir_build_non_exhaustive_match_all_arms_guarded =
match arms with guards don't count towards exhaustivity

mir_build_non_exhaustive_omitted_pattern = some variants are not matched explicitly
.help = ensure that all variants are matched explicitly by adding the suggested match arms
.note = the matched value is of type `{$scrut_ty}` and the `non_exhaustive_omitted_patterns` attribute was found
Expand Down
4 changes: 4 additions & 0 deletions compiler/rustc_mir_build/src/errors.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -432,6 +432,10 @@ impl<'a> IntoDiagnostic<'a> for NonExhaustivePatternsTypeNotEmpty<'_, '_, '_> {
}
}

#[derive(Subdiagnostic)]
#[note(mir_build_non_exhaustive_match_all_arms_guarded)]
pub struct NonExhaustiveMatchAllArmsGuarded;

#[derive(Diagnostic)]
#[diag(mir_build_static_in_pattern, code = "E0158")]
pub struct StaticInPattern {
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5 changes: 5 additions & 0 deletions compiler/rustc_mir_build/src/thir/pattern/check_match.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -830,6 +830,11 @@ fn non_exhaustive_match<'p, 'tcx>(
_ => " or multiple match arms",
},
);

let all_arms_have_guards = arms.iter().all(|arm_id| thir[*arm_id].guard.is_some());
if !is_empty_match && all_arms_have_guards {
err.subdiagnostic(NonExhaustiveMatchAllArmsGuarded);
}
if let Some((span, sugg)) = suggestion {
err.span_suggestion_verbose(span, msg, sugg, Applicability::HasPlaceholders);
} else {
Expand Down
22 changes: 15 additions & 7 deletions tests/ui/pattern/usefulness/empty-match.exhaustive_patterns.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -176,14 +176,15 @@ LL | match_guarded_arm!(0u8);
| ^^^ pattern `_` not covered
|
= note: the matched value is of type `u8`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + _ => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyStruct1` not covered
--> $DIR/empty-match.rs:133:24
--> $DIR/empty-match.rs:134:24
|
LL | match_guarded_arm!(NonEmptyStruct1);
| ^^^^^^^^^^^^^^^ pattern `NonEmptyStruct1` not covered
Expand All @@ -194,14 +195,15 @@ note: `NonEmptyStruct1` defined here
LL | struct NonEmptyStruct1;
| ^^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyStruct1`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyStruct1 => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyStruct2(_)` not covered
--> $DIR/empty-match.rs:137:24
--> $DIR/empty-match.rs:139:24
|
LL | match_guarded_arm!(NonEmptyStruct2(true));
| ^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyStruct2(_)` not covered
Expand All @@ -212,14 +214,15 @@ note: `NonEmptyStruct2` defined here
LL | struct NonEmptyStruct2(bool);
| ^^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyStruct2`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyStruct2(_) => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyUnion1 { .. }` not covered
--> $DIR/empty-match.rs:141:24
--> $DIR/empty-match.rs:144:24
|
LL | match_guarded_arm!((NonEmptyUnion1 { foo: () }));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyUnion1 { .. }` not covered
Expand All @@ -230,14 +233,15 @@ note: `NonEmptyUnion1` defined here
LL | union NonEmptyUnion1 {
| ^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyUnion1`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyUnion1 { .. } => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyUnion2 { .. }` not covered
--> $DIR/empty-match.rs:145:24
--> $DIR/empty-match.rs:149:24
|
LL | match_guarded_arm!((NonEmptyUnion2 { foo: () }));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyUnion2 { .. }` not covered
Expand All @@ -248,14 +252,15 @@ note: `NonEmptyUnion2` defined here
LL | union NonEmptyUnion2 {
| ^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyUnion2`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyUnion2 { .. } => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyEnum1::Foo(_)` not covered
--> $DIR/empty-match.rs:149:24
--> $DIR/empty-match.rs:154:24
|
LL | match_guarded_arm!(NonEmptyEnum1::Foo(true));
| ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyEnum1::Foo(_)` not covered
Expand All @@ -268,14 +273,15 @@ LL | enum NonEmptyEnum1 {
LL | Foo(bool),
| ^^^ not covered
= note: the matched value is of type `NonEmptyEnum1`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyEnum1::Foo(_) => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
--> $DIR/empty-match.rs:153:24
--> $DIR/empty-match.rs:159:24
|
LL | match_guarded_arm!(NonEmptyEnum2::Foo(true));
| ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
Expand All @@ -291,14 +297,15 @@ LL | Foo(bool),
LL | Bar,
| ^^^ not covered
= note: the matched value is of type `NonEmptyEnum2`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ _ if false => {},
LL + NonEmptyEnum2::Foo(_) | NonEmptyEnum2::Bar => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
--> $DIR/empty-match.rs:157:24
--> $DIR/empty-match.rs:164:24
|
LL | match_guarded_arm!(NonEmptyEnum5::V1);
| ^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
Expand All @@ -309,6 +316,7 @@ note: `NonEmptyEnum5` defined here
LL | enum NonEmptyEnum5 {
| ^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyEnum5`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
|
LL ~ _ if false => {},
Expand Down
22 changes: 15 additions & 7 deletions tests/ui/pattern/usefulness/empty-match.normal.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -175,14 +175,15 @@ LL | match_guarded_arm!(0u8);
| ^^^ pattern `_` not covered
|
= note: the matched value is of type `u8`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + _ => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyStruct1` not covered
--> $DIR/empty-match.rs:133:24
--> $DIR/empty-match.rs:134:24
|
LL | match_guarded_arm!(NonEmptyStruct1);
| ^^^^^^^^^^^^^^^ pattern `NonEmptyStruct1` not covered
Expand All @@ -193,14 +194,15 @@ note: `NonEmptyStruct1` defined here
LL | struct NonEmptyStruct1;
| ^^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyStruct1`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyStruct1 => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyStruct2(_)` not covered
--> $DIR/empty-match.rs:137:24
--> $DIR/empty-match.rs:139:24
|
LL | match_guarded_arm!(NonEmptyStruct2(true));
| ^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyStruct2(_)` not covered
Expand All @@ -211,14 +213,15 @@ note: `NonEmptyStruct2` defined here
LL | struct NonEmptyStruct2(bool);
| ^^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyStruct2`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyStruct2(_) => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyUnion1 { .. }` not covered
--> $DIR/empty-match.rs:141:24
--> $DIR/empty-match.rs:144:24
|
LL | match_guarded_arm!((NonEmptyUnion1 { foo: () }));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyUnion1 { .. }` not covered
Expand All @@ -229,14 +232,15 @@ note: `NonEmptyUnion1` defined here
LL | union NonEmptyUnion1 {
| ^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyUnion1`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyUnion1 { .. } => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyUnion2 { .. }` not covered
--> $DIR/empty-match.rs:145:24
--> $DIR/empty-match.rs:149:24
|
LL | match_guarded_arm!((NonEmptyUnion2 { foo: () }));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyUnion2 { .. }` not covered
Expand All @@ -247,14 +251,15 @@ note: `NonEmptyUnion2` defined here
LL | union NonEmptyUnion2 {
| ^^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyUnion2`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyUnion2 { .. } => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyEnum1::Foo(_)` not covered
--> $DIR/empty-match.rs:149:24
--> $DIR/empty-match.rs:154:24
|
LL | match_guarded_arm!(NonEmptyEnum1::Foo(true));
| ^^^^^^^^^^^^^^^^^^^^^^^^ pattern `NonEmptyEnum1::Foo(_)` not covered
Expand All @@ -267,14 +272,15 @@ LL | enum NonEmptyEnum1 {
LL | Foo(bool),
| ^^^ not covered
= note: the matched value is of type `NonEmptyEnum1`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ _ if false => {},
LL + NonEmptyEnum1::Foo(_) => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
--> $DIR/empty-match.rs:153:24
--> $DIR/empty-match.rs:159:24
|
LL | match_guarded_arm!(NonEmptyEnum2::Foo(true));
| ^^^^^^^^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
Expand All @@ -290,14 +296,15 @@ LL | Foo(bool),
LL | Bar,
| ^^^ not covered
= note: the matched value is of type `NonEmptyEnum2`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ _ if false => {},
LL + NonEmptyEnum2::Foo(_) | NonEmptyEnum2::Bar => todo!()
|

error[E0004]: non-exhaustive patterns: `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
--> $DIR/empty-match.rs:157:24
--> $DIR/empty-match.rs:164:24
|
LL | match_guarded_arm!(NonEmptyEnum5::V1);
| ^^^^^^^^^^^^^^^^^ patterns `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
Expand All @@ -308,6 +315,7 @@ note: `NonEmptyEnum5` defined here
LL | enum NonEmptyEnum5 {
| ^^^^^^^^^^^^^
= note: the matched value is of type `NonEmptyEnum5`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown, or multiple match arms
|
LL ~ _ if false => {},
Expand Down
8 changes: 8 additions & 0 deletions tests/ui/pattern/usefulness/empty-match.rs
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Expand Up @@ -128,34 +128,42 @@ fn main() {

match_guarded_arm!(0u8); //~ ERROR `_` not covered
//~| NOTE the matched value is of type
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE pattern `_` not covered
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!(NonEmptyStruct1); //~ ERROR `NonEmptyStruct1` not covered
//~| NOTE pattern `NonEmptyStruct1` not covered
//~| NOTE the matched value is of type
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!(NonEmptyStruct2(true)); //~ ERROR `NonEmptyStruct2(_)` not covered
//~| NOTE the matched value is of type
//~| NOTE pattern `NonEmptyStruct2(_)` not covered
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!((NonEmptyUnion1 { foo: () })); //~ ERROR `NonEmptyUnion1 { .. }` not covered
//~| NOTE the matched value is of type
//~| NOTE pattern `NonEmptyUnion1 { .. }` not covered
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!((NonEmptyUnion2 { foo: () })); //~ ERROR `NonEmptyUnion2 { .. }` not covered
//~| NOTE the matched value is of type
//~| NOTE pattern `NonEmptyUnion2 { .. }` not covered
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!(NonEmptyEnum1::Foo(true)); //~ ERROR `NonEmptyEnum1::Foo(_)` not covered
//~| NOTE the matched value is of type
//~| NOTE pattern `NonEmptyEnum1::Foo(_)` not covered
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!(NonEmptyEnum2::Foo(true)); //~ ERROR `NonEmptyEnum2::Foo(_)` and `NonEmptyEnum2::Bar` not covered
//~| NOTE the matched value is of type
//~| NOTE patterns `NonEmptyEnum2::Foo(_)` and
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
match_guarded_arm!(NonEmptyEnum5::V1); //~ ERROR `NonEmptyEnum5::V1`, `NonEmptyEnum5::V2`, `NonEmptyEnum5::V3` and 2 more not covered
//~| NOTE the matched value is of type
//~| NOTE patterns `NonEmptyEnum5::V1`,
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE in this expansion of match_guarded_arm!
}
17 changes: 11 additions & 6 deletions tests/ui/pattern/usefulness/issue-3601.rs
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@@ -1,19 +1,19 @@
#![feature(box_patterns)]

struct HTMLImageData {
image: Option<String>
image: Option<String>,
}

struct ElementData {
kind: Box<ElementKind>
kind: Box<ElementKind>,
}

enum ElementKind {
HTMLImageElement(HTMLImageData)
HTMLImageElement(HTMLImageData),
}

enum NodeKind {
Element(ElementData)
Element(ElementData),
}

struct NodeData {
Expand All @@ -27,8 +27,13 @@ fn main() {

// n.b. span could be better
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why did you remove this comment?

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I thought that was in reference to the lack of the comments annotating the expected diagnostic in the compiletest. Is that not right?

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I think it was about the span that the diagnostic highlighted?

match n.kind {
box NodeKind::Element(ed) => match ed.kind { //~ ERROR non-exhaustive patterns
box ElementKind::HTMLImageElement(ref d) if d.image.is_some() => { true }
box NodeKind::Element(ed) => match ed.kind {
//~^ ERROR non-exhaustive patterns
//~| NOTE the matched value is of type
//~| NOTE match arms with guards don't count towards exhaustivity
//~| NOTE pattern `box _` not covered
//~| NOTE `Box<ElementKind>` defined here
box ElementKind::HTMLImageElement(ref d) if d.image.is_some() => true,
},
};
}
5 changes: 3 additions & 2 deletions tests/ui/pattern/usefulness/issue-3601.stderr
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Expand Up @@ -7,10 +7,11 @@ LL | box NodeKind::Element(ed) => match ed.kind {
note: `Box<ElementKind>` defined here
--> $SRC_DIR/alloc/src/boxed.rs:LL:COL
= note: the matched value is of type `Box<ElementKind>`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ box ElementKind::HTMLImageElement(ref d) if d.image.is_some() => { true },
LL + box _ => todo!()
LL ~ box ElementKind::HTMLImageElement(ref d) if d.image.is_some() => true,
LL ~ box _ => todo!(),
|

error: aborting due to previous error
Expand Down
1 change: 1 addition & 0 deletions tests/ui/pattern/usefulness/match-non-exhaustive.rs
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@@ -1,4 +1,5 @@
fn main() {
match 0 { 1 => () } //~ ERROR non-exhaustive patterns
match 0 { 0 if false => () } //~ ERROR non-exhaustive patterns
//-| NOTE match arms with guards don't count towards exhaustivity
}
1 change: 1 addition & 0 deletions tests/ui/pattern/usefulness/match-non-exhaustive.stderr
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Expand Up @@ -17,6 +17,7 @@ LL | match 0 { 0 if false => () }
| ^ pattern `_` not covered
|
= note: the matched value is of type `i32`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL | match 0 { 0 if false => (), _ => todo!() }
Expand Down