pub enum ObligationCauseCode<'tcx> {
Show 62 variants MiscObligation, SliceOrArrayElem, TupleElem, ProjectionWf(AliasTy<'tcx>), ItemObligation(DefId), BindingObligation(DefId, Span), ExprItemObligation(DefId, HirId, usize), ExprBindingObligation(DefId, Span, HirId, usize), ReferenceOutlivesReferent(Ty<'tcx>), ObjectTypeBound(Ty<'tcx>, Region<'tcx>), Coercion { source: Ty<'tcx>, target: Ty<'tcx>, }, AssignmentLhsSized, TupleInitializerSized, StructInitializerSized, VariableType(HirId), SizedArgumentType(Option<Span>), SizedReturnType, SizedYieldType, InlineAsmSized, SizedClosureCapture(LocalDefId), SizedGeneratorInterior(LocalDefId), RepeatElementCopy { is_const_fn: bool, }, FieldSized { adt_kind: AdtKind, span: Span, last: bool, }, ConstSized, SharedStatic, BuiltinDerivedObligation(DerivedObligationCause<'tcx>), ImplDerivedObligation(Box<ImplDerivedObligationCause<'tcx>, Global>), DerivedObligation(DerivedObligationCause<'tcx>), FunctionArgumentObligation { arg_hir_id: HirId, call_hir_id: HirId, parent_code: InternedObligationCauseCode<'tcx>, }, CompareImplItemObligation { impl_item_def_id: LocalDefId, trait_item_def_id: DefId, kind: AssocKind, }, CheckAssociatedTypeBounds { impl_item_def_id: LocalDefId, trait_item_def_id: DefId, }, ExprAssignable, MatchExpressionArm(Box<MatchExpressionArmCause<'tcx>, Global>), Pattern { span: Option<Span>, root_ty: Ty<'tcx>, origin_expr: bool, }, ConstPatternStructural, IfExpression(Box<IfExpressionCause<'tcx>, Global>), IfExpressionWithNoElse, MainFunctionType, StartFunctionType, LangFunctionType(Symbol), IntrinsicType, LetElse, MethodReceiver, UnifyReceiver(Box<UnifyReceiverContext<'tcx>, Global>), ReturnNoExpression, ReturnValue(HirId), ReturnType, OpaqueReturnType(Option<(Ty<'tcx>, Span)>), BlockTailExpression(HirId, MatchSource), TrivialBound, OpaqueType, AwaitableExpr(Option<HirId>), ForLoopIterator, QuestionMark, WellFormed(Option<WellFormedLoc>), MatchImpl(ObligationCause<'tcx>, DefId), BinOp { rhs_span: Option<Span>, is_lit: bool, output_ty: Option<Ty<'tcx>>, }, AscribeUserTypeProvePredicate(Span), RustCall, DropImpl, ConstParam(Ty<'tcx>), TypeAlias(InternedObligationCauseCode<'tcx>, Span, DefId),
}

Variants§

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MiscObligation

Not well classified or should be obvious from the span.

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SliceOrArrayElem

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

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TupleElem

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

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ProjectionWf(AliasTy<'tcx>)

This is the trait reference from the given projection.

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ItemObligation(DefId)

Must satisfy all of the where-clause predicates of the given item.

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BindingObligation(DefId, Span)

Like ItemObligation, but carries the span of the predicate when it can be identified.

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ExprItemObligation(DefId, HirId, usize)

Like ItemObligation, but carries the HirId of the expression that caused the obligation, and the usize indicates exactly which predicate it is in the list of instantiated predicates.

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ExprBindingObligation(DefId, Span, HirId, usize)

Combines ExprItemObligation and BindingObligation.

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ReferenceOutlivesReferent(Ty<'tcx>)

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

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

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

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Coercion

Fields

§source: Ty<'tcx>
§target: Ty<'tcx>

Obligation incurred due to a coercion.

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AssignmentLhsSized

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

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TupleInitializerSized

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

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StructInitializerSized

S { ... } must be Sized.

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VariableType(HirId)

Type of each variable must be Sized.

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SizedArgumentType(Option<Span>)

Argument type must be Sized.

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SizedReturnType

Return type must be Sized.

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SizedYieldType

Yield type must be Sized.

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InlineAsmSized

Inline asm operand type must be Sized.

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SizedClosureCapture(LocalDefId)

Captured closure type must be Sized.

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SizedGeneratorInterior(LocalDefId)

Types live across generator yields must be Sized.

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RepeatElementCopy

Fields

§is_const_fn: bool

If element is a const fn we display a help message suggesting to move the function call to a new const item while saying that T doesn’t implement Copy.

[expr; N] requires type_of(expr): Copy.

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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.

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ConstSized

Constant expressions must be sized.

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SharedStatic

static items must have Sync type.

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BuiltinDerivedObligation(DerivedObligationCause<'tcx>)

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ImplDerivedObligation(Box<ImplDerivedObligationCause<'tcx>, Global>)

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DerivedObligation(DerivedObligationCause<'tcx>)

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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: InternedObligationCauseCode<'tcx>

The obligation introduced by this argument.

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CompareImplItemObligation

Fields

§impl_item_def_id: LocalDefId
§trait_item_def_id: DefId

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

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CheckAssociatedTypeBounds

Fields

§impl_item_def_id: LocalDefId
§trait_item_def_id: DefId

Checking that the bounds of a trait’s associated type hold for a given impl

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ExprAssignable

Checking that this expression can be assigned to its target.

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MatchExpressionArm(Box<MatchExpressionArmCause<'tcx>, Global>)

Computing common supertype in the arms of a match expression

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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.

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ConstPatternStructural

Constants in patterns must have Structural type.

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IfExpression(Box<IfExpressionCause<'tcx>, Global>)

Computing common supertype in an if expression

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IfExpressionWithNoElse

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

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MainFunctionType

main has wrong type

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StartFunctionType

start has wrong type

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LangFunctionType(Symbol)

language function has wrong type

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IntrinsicType

Intrinsic has wrong type

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LetElse

A let else block does not diverge

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MethodReceiver

Method receiver

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UnifyReceiver(Box<UnifyReceiverContext<'tcx>, Global>)

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ReturnNoExpression

return with no expression

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ReturnValue(HirId)

return with an expression

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ReturnType

Return type of this function

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OpaqueReturnType(Option<(Ty<'tcx>, Span)>)

Opaque return type of this function

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BlockTailExpression(HirId, MatchSource)

Block implicit return

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TrivialBound

#[feature(trivial_bounds)] is not enabled

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OpaqueType

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

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AwaitableExpr(Option<HirId>)

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ForLoopIterator

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QuestionMark

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WellFormed(Option<WellFormedLoc>)

Well-formed checking. If a WellFormedLoc is provided, then it will be used to perform 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)

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MatchImpl(ObligationCause<'tcx>, DefId)

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

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BinOp

Fields

§rhs_span: Option<Span>
§is_lit: bool
§output_ty: Option<Ty<'tcx>>
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AscribeUserTypeProvePredicate(Span)

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RustCall

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DropImpl

Obligations to prove that a std::ops::Drop impl is not stronger than the ADT it’s being implemented for.

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ConstParam(Ty<'tcx>)

Requirement for a const N: Ty to implement Ty: ConstParamTy

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TypeAlias(InternedObligationCauseCode<'tcx>, Span, DefId)

Obligations emitted during the normalization of a weak type alias.

Auto Trait Implementations§

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impl<'tcx> !RefUnwindSafe for ObligationCauseCode<'tcx>

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impl<'tcx> !Send for ObligationCauseCode<'tcx>

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impl<'tcx> !Sync for ObligationCauseCode<'tcx>

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impl<'tcx> Unpin for ObligationCauseCode<'tcx>

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impl<'tcx> !UnwindSafe for ObligationCauseCode<'tcx>

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::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
  • ExprItemObligation: 31 bytes
  • ExprBindingObligation: 39 bytes
  • ReferenceOutlivesReferent: 15 bytes
  • ObjectTypeBound: 23 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
  • InlineAsmSized: 0 bytes
  • SizedClosureCapture: 7 bytes
  • SizedGeneratorInterior: 7 bytes
  • RepeatElementCopy: 1 byte
  • FieldSized: 11 bytes
  • ConstSized: 0 bytes
  • SharedStatic: 0 bytes
  • BuiltinDerivedObligation: 47 bytes
  • ImplDerivedObligation: 15 bytes
  • DerivedObligation: 47 bytes
  • FunctionArgumentObligation: 31 bytes
  • CompareImplItemObligation: 15 bytes
  • CheckAssociatedTypeBounds: 15 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
  • LangFunctionType: 7 bytes
  • IntrinsicType: 0 bytes
  • LetElse: 0 bytes
  • MethodReceiver: 0 bytes
  • UnifyReceiver: 15 bytes
  • ReturnNoExpression: 0 bytes
  • ReturnValue: 11 bytes
  • ReturnType: 0 bytes
  • OpaqueReturnType: 23 bytes
  • BlockTailExpression: 19 bytes
  • TrivialBound: 0 bytes
  • OpaqueType: 0 bytes
  • AwaitableExpr: 11 bytes
  • ForLoopIterator: 0 bytes
  • QuestionMark: 0 bytes
  • WellFormed: 11 bytes
  • MatchImpl: 39 bytes
  • BinOp: 23 bytes
  • AscribeUserTypeProvePredicate: 11 bytes
  • RustCall: 0 bytes
  • DropImpl: 0 bytes
  • ConstParam: 15 bytes
  • TypeAlias: 31 bytes