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Rollup merge of #113019 - ericmarkmartin:warning-for-guard-non-exhaustion, r=fee1-dead

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add note for non-exhaustive matches with guards

Associated issue: #92197

When a match statement includes guards on every match arm (and is therefore necessarily non-exhaustive), add a note to the error E0004 diagnostic noting this.
This commit is contained in:
Dylan DPC 2023-06-28 18:28:47 +05:30 committed by GitHub
commit e4e1a995dc
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10 changed files with 66 additions and 22 deletions
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3
compiler/rustc_mir_build/messages.ftl
View File

@ -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

4
compiler/rustc_mir_build/src/errors.rs
View File

@ -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 {

5
compiler/rustc_mir_build/src/thir/pattern/check_match.rs
View File

@ -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 {

22
tests/ui/pattern/usefulness/empty-match.exhaustive_patterns.stderr
View File

@ -176,6 +176,7 @@ 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 => {},
@ -183,7 +184,7 @@ 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
@ -194,6 +195,7 @@ 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 => {},
@ -201,7 +203,7 @@ 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
@ -212,6 +214,7 @@ 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 => {},
@ -219,7 +222,7 @@ 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
@ -230,6 +233,7 @@ 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 => {},
@ -237,7 +241,7 @@ 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
@ -248,6 +252,7 @@ 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 => {},
@ -255,7 +260,7 @@ 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
@ -268,6 +273,7 @@ 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 => {},
@ -275,7 +281,7 @@ 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
@ -291,6 +297,7 @@ 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 => {},
@ -298,7 +305,7 @@ 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
@ -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 => {},

22
tests/ui/pattern/usefulness/empty-match.normal.stderr
View File

@ -175,6 +175,7 @@ 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 => {},
@ -182,7 +183,7 @@ 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
@ -193,6 +194,7 @@ 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 => {},
@ -200,7 +202,7 @@ 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
@ -211,6 +213,7 @@ 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 => {},
@ -218,7 +221,7 @@ 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
@ -229,6 +232,7 @@ 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 => {},
@ -236,7 +240,7 @@ 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
@ -247,6 +251,7 @@ 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 => {},
@ -254,7 +259,7 @@ 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
@ -267,6 +272,7 @@ 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 => {},
@ -274,7 +280,7 @@ 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
@ -290,6 +296,7 @@ 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 => {},
@ -297,7 +304,7 @@ 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
@ -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 => {},

8
tests/ui/pattern/usefulness/empty-match.rs
View File

@ -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
tests/ui/pattern/usefulness/issue-3601.rs
View File

@ -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 {
@ -27,8 +27,13 @@ fn main() {
// n.b. span could be better
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
tests/ui/pattern/usefulness/issue-3601.stderr
View File

@ -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

1
tests/ui/pattern/usefulness/match-non-exhaustive.rs
View File

@ -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
tests/ui/pattern/usefulness/match-non-exhaustive.stderr
View File

@ -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!() }