pub enum ObligationCauseCode<'tcx> {
Show 53 variants MiscObligation, SliceOrArrayElem, TupleElem, ProjectionWf(ProjectionTy<'tcx>), ItemObligation(DefId), BindingObligation(DefIdSpan), ReferenceOutlivesReferent(Ty<'tcx>), ObjectTypeBound(Ty<'tcx>, Region<'tcx>), ObjectCastObligation(Ty<'tcx>), Coercion { source: Ty<'tcx>, target: Ty<'tcx>, }, AssignmentLhsSized, TupleInitializerSized, StructInitializerSized, VariableType(HirId), SizedArgumentType(Option<Span>), SizedReturnType, SizedYieldType, SizedBoxType, InlineAsmSized, RepeatVec(bool), FieldSized { adt_kind: AdtKind, span: Span, last: bool, }, ConstSized, SharedStatic, BuiltinDerivedObligation(DerivedObligationCause<'tcx>), ImplDerivedObligation(DerivedObligationCause<'tcx>), DerivedObligation(DerivedObligationCause<'tcx>), FunctionArgumentObligation { arg_hir_id: HirId, call_hir_id: HirId, parent_code: Lrc<ObligationCauseCode<'tcx>>, }, CompareImplConstObligation, CompareImplMethodObligation { impl_item_def_id: DefId, trait_item_def_id: DefId, }, CompareImplTypeObligation { impl_item_def_id: DefId, trait_item_def_id: DefId, }, ExprAssignable, MatchExpressionArm(Box<MatchExpressionArmCause<'tcx>>), Pattern { span: Option<Span>, root_ty: Ty<'tcx>, origin_expr: bool, }, ConstPatternStructural, IfExpression(Box<IfExpressionCause>), IfExpressionWithNoElse, MainFunctionType, StartFunctionType, IntrinsicType, LetElse, MethodReceiver, UnifyReceiver(Box<UnifyReceiverContext<'tcx>>), ReturnNoExpression, ReturnValue(HirId), ReturnType, BlockTailExpression(HirId), TrivialBound, OpaqueType, AwaitableExpr(Option<HirId>), ForLoopIterator, QuestionMark, WellFormed(Option<WellFormedLoc>), MatchImpl(ObligationCause<'tcx>, DefId),
}

Variants

MiscObligation

Not well classified or should be obvious from the span.

SliceOrArrayElem

A slice or array is WF only if T: Sized.

TupleElem

A tuple is WF only if its middle elements are Sized.

ProjectionWf(ProjectionTy<'tcx>)

This is the trait reference from the given projection.

ItemObligation(DefId)

In an impl of trait X for type Y, type Y must also implement all supertraits of X.

BindingObligation(DefIdSpan)

Like ItemObligation, but with extra detail on the source of the obligation.

ReferenceOutlivesReferent(Ty<'tcx>)

A type like &'a T is WF only if T: 'a.

ObjectTypeBound(Ty<'tcx>, Region<'tcx>)

A type like Box<Foo<'a> + 'b> is WF only if 'b: 'a.

ObjectCastObligation(Ty<'tcx>)

Obligation incurred due to an object cast.

Coercion

Fields

source: Ty<'tcx>
target: Ty<'tcx>

Obligation incurred due to a coercion.

AssignmentLhsSized

Various cases where expressions must be Sized / Copy / etc. L = X implies that L is Sized.

TupleInitializerSized

(x1, .., xn) must be Sized.

StructInitializerSized

S { ... } must be Sized.

VariableType(HirId)

Type of each variable must be Sized.

SizedArgumentType(Option<Span>)

Argument type must be Sized.

SizedReturnType

Return type must be Sized.

SizedYieldType

Yield type must be Sized.

SizedBoxType

Box expression result type must be Sized.

InlineAsmSized

Inline asm operand type must be Sized.

RepeatVec(bool)

[T, ..n] implies that T must be Copy. If the function in the array repeat expression is a const fn, display a help message suggesting to move the function call to a new const item while saying that T doesn’t implement Copy.

FieldSized

Fields

adt_kind: AdtKind
span: Span
last: bool

Types of fields (other than the last, except for packed structs) in a struct must be sized.

ConstSized

Constant expressions must be sized.

SharedStatic

static items must have Sync type.

BuiltinDerivedObligation(DerivedObligationCause<'tcx>)

ImplDerivedObligation(DerivedObligationCause<'tcx>)

DerivedObligation(DerivedObligationCause<'tcx>)

FunctionArgumentObligation

Fields

arg_hir_id: HirId

The node of the relevant argument in the function call.

call_hir_id: HirId

The node of the function call.

parent_code: Lrc<ObligationCauseCode<'tcx>>

The obligation introduced by this argument.

CompareImplConstObligation

Error derived when matching traits/impls; see ObligationCause for more details

CompareImplMethodObligation

Fields

impl_item_def_id: DefId
trait_item_def_id: DefId

Error derived when matching traits/impls; see ObligationCause for more details

CompareImplTypeObligation

Fields

impl_item_def_id: DefId
trait_item_def_id: DefId

Error derived when matching traits/impls; see ObligationCause for more details

ExprAssignable

Checking that this expression can be assigned where it needs to be

MatchExpressionArm(Box<MatchExpressionArmCause<'tcx>>)

Computing common supertype in the arms of a match expression

Pattern

Fields

span: Option<Span>

The span of the scrutinee or type expression which caused the root_ty type.

root_ty: Ty<'tcx>

The root expected type induced by a scrutinee or type expression.

origin_expr: bool

Whether the Span came from an expression or a type expression.

Type error arising from type checking a pattern against an expected type.

ConstPatternStructural

Constants in patterns must have Structural type.

IfExpression(Box<IfExpressionCause>)

Computing common supertype in an if expression

IfExpressionWithNoElse

Computing common supertype of an if expression with no else counter-part

MainFunctionType

main has wrong type

StartFunctionType

start has wrong type

IntrinsicType

Intrinsic has wrong type

LetElse

A let else block does not diverge

MethodReceiver

Method receiver

UnifyReceiver(Box<UnifyReceiverContext<'tcx>>)

ReturnNoExpression

return with no expression

ReturnValue(HirId)

return with an expression

ReturnType

Return type of this function

BlockTailExpression(HirId)

Block implicit return

TrivialBound

#[feature(trivial_bounds)] is not enabled

OpaqueType

If X is the concrete type of an opaque type impl Y, then X must implement Y

AwaitableExpr(Option<HirId>)

ForLoopIterator

QuestionMark

WellFormed(Option<WellFormedLoc>)

Well-formed checking. If a WellFormedLoc is provided, then it will be used to eprform HIR-based wf checking after an error occurs, in order to generate a more precise error span. This is purely for diagnostic purposes - it is always correct to use MiscObligation instead, or to specify WellFormed(None)

MatchImpl(ObligationCause<'tcx>, DefId)

From match_impl. The cause for us having to match an impl, and the DefId we are matching against.

Implementations

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 48 bytes

Size for each variant:

  • MiscObligation: 0 bytes
  • SliceOrArrayElem: 0 bytes
  • TupleElem: 0 bytes
  • ProjectionWf: 23 bytes
  • ItemObligation: 11 bytes
  • BindingObligation: 19 bytes
  • ReferenceOutlivesReferent: 15 bytes
  • ObjectTypeBound: 23 bytes
  • ObjectCastObligation: 15 bytes
  • Coercion: 23 bytes
  • AssignmentLhsSized: 0 bytes
  • TupleInitializerSized: 0 bytes
  • StructInitializerSized: 0 bytes
  • VariableType: 11 bytes
  • SizedArgumentType: 15 bytes
  • SizedReturnType: 0 bytes
  • SizedYieldType: 0 bytes
  • SizedBoxType: 0 bytes
  • InlineAsmSized: 0 bytes
  • RepeatVec: 1 byte
  • FieldSized: 11 bytes
  • ConstSized: 0 bytes
  • SharedStatic: 0 bytes
  • BuiltinDerivedObligation: 47 bytes
  • ImplDerivedObligation: 47 bytes
  • DerivedObligation: 47 bytes
  • FunctionArgumentObligation: 31 bytes
  • CompareImplConstObligation: 0 bytes
  • CompareImplMethodObligation: 19 bytes
  • CompareImplTypeObligation: 19 bytes
  • ExprAssignable: 0 bytes
  • MatchExpressionArm: 15 bytes
  • Pattern: 23 bytes
  • ConstPatternStructural: 0 bytes
  • IfExpression: 15 bytes
  • IfExpressionWithNoElse: 0 bytes
  • MainFunctionType: 0 bytes
  • StartFunctionType: 0 bytes
  • IntrinsicType: 0 bytes
  • LetElse: 0 bytes
  • MethodReceiver: 0 bytes
  • UnifyReceiver: 15 bytes
  • ReturnNoExpression: 0 bytes
  • ReturnValue: 11 bytes
  • ReturnType: 0 bytes
  • BlockTailExpression: 11 bytes
  • TrivialBound: 0 bytes
  • OpaqueType: 0 bytes
  • AwaitableExpr: 11 bytes
  • ForLoopIterator: 0 bytes
  • QuestionMark: 0 bytes
  • WellFormed: 11 bytes
  • MatchImpl: 39 bytes