36public static NullableFlowState GetNullableState(ArrayBuilder<TypeWithState> types) 38NullableFlowState result = NullableFlowState.NotNull;

126public VisitResult(TypeSymbol? type, NullableAnnotation annotation, NullableFlowState state) 216private static readonly TypeWithState _invalidType = TypeWithState.Create(new UnsupportedMetadataTypeSymbol(), NullableFlowState.NotNull); 802var memberState = GetState(ref state, slot); 803var badState = symbolType.Type.IsPossiblyNullableReferenceTypeTypeParameter() && (annotations & FlowAnalysisAnnotations.NotNull) == 0 804? NullableFlowState.MaybeDefault 805: NullableFlowState.MaybeNull; 861SetState(ref this.State, memberSlot, type.Type.IsPossiblyNullableReferenceTypeTypeParameter() ? NullableFlowState.MaybeDefault : NullableFlowState.MaybeNull); 1156var parameterState = GetState(ref state, memberSlot); 1188SetState(ref this.State, memberSlot, NullableFlowState.MaybeNull); 1301var parameterState = GetState(ref state, slot); 1357var parameterState = GetState(ref stateWhen, slot); 1384private void EnforceNotNullIfNotNull(SyntaxNode? syntaxOpt, LocalState state, ImmutableArray<ParameterSymbol> parameters, ImmutableHashSet<string> inputParamNames, NullableFlowState outputState, ParameterSymbol? outputParam) 1971private NullableFlowState GetState(ref LocalState state, int slot) 1974return NullableFlowState.NotNull; 1980private void SetState(ref LocalState state, int slot, NullableFlowState value, bool useNotNullsAsDefault = false) 2002private NullableFlowState GetDefaultState(ref LocalState state, int slot) 2007return NullableFlowState.NotNull; 2037return NullableFlowState.NotNull; 2366private static bool ShouldReportNullableAssignment(TypeWithAnnotations type, NullableFlowState state) 2383case NullableFlowState.NotNull: 2385case NullableFlowState.MaybeNull: 2461valueType.State == NullableFlowState.MaybeDefault; 2643var newState = valueType.State; 2746NullableFlowState value = isDefaultValue ? NullableFlowState.MaybeNull : fieldOrPropertyType.ToTypeWithState().State; 2758NullableFlowState.NotNull; 2806/// and the new state is not <see cref="NullableFlowState.NotNull"/>, this method should be called to perform the 2810private void SetStateAndTrackForFinally(ref LocalState state, int slot, NullableFlowState newState) 2814if (newState != NullableFlowState.NotNull && NonMonotonicState.HasValue) 2899private NullableFlowState GetDefaultState(Symbol symbol) 2992var state = GetParameterState(parameterType, parameter.FlowAnalysisAnnotations).State; 3030return TypeWithState.Create(parameterType.Type, NullableFlowState.MaybeDefault); 3035return TypeWithState.Create(parameterType.Type, NullableFlowState.NotNull); 3339SetState(ref state, slot, NullableFlowState.NotNull); 3838SetResultType(node, TypeWithState.Create(null, NullableFlowState.NotNull)); 3846SetResultType(node, TypeWithState.Create(null, NullableFlowState.NotNull)); 4000NullableFlowState resultState = getResultState(node, collectionKind); 4006static NullableFlowState getResultState(BoundCollectionExpression node, CollectionExpressionTypeKind collectionKind) 4018return NullableFlowState.NotNull; 4087(int slot, NullableFlowState resultState, Func<TypeSymbol, MethodSymbol?, int>? initialStateInferenceCompletion) = 4107NullableFlowState resultState, 4136NullableFlowState resultState) 4138Debug.Assert(resultState == NullableFlowState.NotNull); 4170(int slot, NullableFlowState resultState, Func<TypeSymbol, MethodSymbol?, int>? completion) inferInitialObjectState( 4178return (-1, NullableFlowState.NotNull, inferInitialObjectStateAsContinuation(node, arguments, argumentResults, hasObjectInitializer)); 4184var resultState = NullableFlowState.NotNull; 4216resultState = NullableFlowState.MaybeNull; 4251Debug.Assert(resultState == NullableFlowState.NotNull); 4385var result = new VisitResult(objectInitializer.Type, NullableAnnotation.NotAnnotated, NullableFlowState.NotNull); 4575SetAnalyzedNullability(node.ImplicitReceiverOpt, new VisitResult(node.ImplicitReceiverOpt.Type, NullableAnnotation.NotAnnotated, NullableFlowState.NotNull)); 4633SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.NotNull)); 4638var resultType = TypeWithState.Create(node.Type, NullableFlowState.NotNull); 4746SetResultType(node, TypeWithState.Create(anonymousType, NullableFlowState.NotNull)); 4778SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.NotNull)); 4783SetResultType(node, TypeWithState.Create(arrayType, NullableFlowState.NotNull)); 4859var elementState = BestTypeInferrer.GetNullableState(expressionTypes); 5061NullableFlowState resultState = NullableFlowState.NotNull; 5089resultState = NullableFlowState.MaybeNull; // Delegate removal can produce null. 5092resultState = NullableFlowState.NotNull; 5681SetState(ref stateToUpdate, slot, NullableFlowState.NotNull); 5710SetState(ref state, slot, NullableFlowState.NotNull); 5735if (GetState(ref state, slot) == NullableFlowState.NotNull) 5738SetState(ref state, slot, NullableFlowState.MaybeNull); 5767SetState(ref state, childSlot, NullableFlowState.NotNull); 5846SetState(ref this.State, leftSlot, NullableFlowState.NotNull); 5901BoundNullCoalescingOperatorResultKind.NoCommonType => (node.Type, NullableFlowState.NotNull), 5906BoundNullCoalescingOperatorResultKind.RightDynamicType => (rightResultType!, NullableFlowState.NotNull), 5913(TypeSymbol ResultType, NullableFlowState LeftState) getLeftResultType(TypeSymbol leftType, TypeSymbol rightType) 5923return (rightType, NullableFlowState.NotNull); 5928return (leftType, NullableFlowState.NotNull); 5931(TypeSymbol ResultType, NullableFlowState LeftState) getResultStateWithRightType(TypeSymbol leftType, TypeSymbol rightType) 5943TypeWithState.Create(leftType, NullableFlowState.NotNull), 5954return (rightType, NullableFlowState.NotNull); 6127SetResultType(node, TypeWithState.Create(resultType, NullableFlowState.MaybeDefault)); 6182var rValueState = consequenceRValue.State.Join(alternativeRValue.State); 6290NullableFlowState resultState; 6450SetResultType(node, TypeWithState.Create(rvalueType, NullableFlowState.NotNull)); 6920private NullableFlowState LearnFromCompareExchangeMethod(in CompareExchangeInfo compareExchangeInfo) 6940return NullableFlowState.NotNull; 6950var valueFlowState = compareExchangeInfo.Results[valueIndex].RValueType.State; 6957var locationFlowState = compareExchangeInfo.Results[locationIndex].RValueType.State; 7074return TypeWithState.Create(typeWithState.Type, NullableFlowState.NotNull); 7079return TypeWithState.Create(typeWithState.Type, NullableFlowState.MaybeDefault); 7664SetState(ref state, memberSlot, NullableFlowState.NotNull); 7969var adjustedState = LearnFromCompareExchangeMethod(in compareExchangeInfoOpt); 8093return TypeWithState.Create(typeWithState.Type, NullableFlowState.MaybeDefault); 8099return TypeWithState.Create(typeWithState.Type, NullableFlowState.NotNull); 8114return TypeWithState.Create(typeWithState.Type, NullableFlowState.MaybeDefault); 8118return TypeWithState.Create(typeWithState.Type, NullableFlowState.NotNull); 8133return TypeWithState.Create(typeWithState.Type, NullableFlowState.MaybeDefault); 8137return TypeWithState.Create(typeWithState.Type, NullableFlowState.NotNull); 8649NullableFlowState state = GetState(ref this.State, slot); 8924SetResultType(node, TypeWithState.Create(null, NullableFlowState.NotNull)); 8931SetState(ref this.State, slot, NullableFlowState.NotNull); 8949SetResultType(node, TypeWithState.Create(tupleOpt, NullableFlowState.NotNull)); 9071SetState(ref this.State, targetFieldSlot, NullableFlowState.NotNull); 9088SetState(ref this.State, targetFieldSlot, NullableFlowState.NotNull); 9324NullableFlowState resultState = NullableFlowState.NotNull; 9356resultState = NullableFlowState.NotNull; 9380return TypeWithState.Create(targetType, NullableFlowState.NotNull); 9386resultState = NullableFlowState.NotNull; 9390resultState = NullableFlowState.NotNull; 9395resultState = NullableFlowState.NotNull; 9435resultState = NullableFlowState.NotNull; 9559resultState = NullableFlowState.NotNull; 9629static TypeWithState calculateResultType(TypeWithAnnotations targetTypeWithNullability, bool fromExplicitCast, NullableFlowState resultState, bool isSuppressed, TypeSymbol targetType) 9633resultState = NullableFlowState.NotNull; 9638resultState = targetType?.IsTypeParameterDisallowingAnnotationInCSharp8() == true ? NullableFlowState.MaybeDefault : NullableFlowState.MaybeNull; 9645static NullableFlowState getReferenceConversionResultState(TypeWithAnnotations targetType, TypeWithState operandType) 9647var state = operandType.State; 9650case NullableFlowState.MaybeNull: 9656return NullableFlowState.MaybeDefault; 9662return (annotation == NullableAnnotation.Annotated) ? NullableFlowState.MaybeDefault : NullableFlowState.MaybeNull; 9666case NullableFlowState.MaybeDefault: 9669return NullableFlowState.MaybeNull; 9679static NullableFlowState getBoxingConversionResultState(TypeWithAnnotations targetType, TypeWithState operandType) 9681var state = operandType.State; 9682if (state == NullableFlowState.MaybeNull) 9687return NullableFlowState.MaybeDefault; 9697return (annotation == NullableAnnotation.Annotated) ? NullableFlowState.MaybeDefault : NullableFlowState.MaybeNull; 9707static NullableFlowState getUnboxingConversionResultState(TypeWithState operandType) 9709var state = operandType.State; 9710if (state == NullableFlowState.MaybeNull) 9712return NullableFlowState.MaybeDefault; 9717static NullableFlowState getConversionResultState(TypeWithState operandType) 9719var state = operandType.State; 9720if (state == NullableFlowState.MaybeNull) 9722return NullableFlowState.MaybeDefault; 9858var resultType = TypeWithState.Create(targetType, NullableFlowState.NotNull); 9901NullableFlowState operandState = operandType.State; 10021private TypeWithState GetLiftedReturnType(TypeWithAnnotations returnType, NullableFlowState operandState) 10025NullableFlowState state = returnType.ToTypeWithState().State.Join(operandState); 10042private TypeWithState GetLiftedReturnTypeIfNecessary(bool isLifted, TypeWithAnnotations returnType, NullableFlowState operandState) 10138var result = TypeWithState.Create(delegateType, NullableFlowState.NotNull); 10435var rvalueResult = TypeWithState.Create(node.Type, NullableFlowState.NotNull); 10855var valueBeforeNullableWrapping = TypeWithState.Create(underlyingType.Type, NullableFlowState.NotNull); 10985SetResultType(node, TypeWithState.Create(receiverType.Type, NullableFlowState.NotNull)); 11009SetResultType(node, TypeWithState.Create(opType.Type, NullableFlowState.NotNull)); 11163SetResultType(node, TypeWithState.Create(receiverType.Type, NullableFlowState.NotNull)); 11191SetResultType(node, TypeWithState.Create(opType.Type, NullableFlowState.NotNull)); 11493var state = GetState(ref this.State, slot); 11505SetState(ref this.StateWhenTrue, containingSlot, NullableFlowState.NotNull); 11729if (enumeratorReturnType.State != NullableFlowState.NotNull) 11810var state = NullableFlowState.NotNull; 12007TypeWithState.Create(node.Type, node.OperatorKind.IsLifted() ? argumentResult.State : NullableFlowState.NotNull); 12275SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.NotNull)); 12297SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.MaybeDefault)); 12312SetState(ref this.State, slot, NullableFlowState.NotNull); 12358NullableFlowState resultState = NullableFlowState.NotNull; 12373resultState = NullableFlowState.MaybeDefault; 12411SetResultType(node, TypeWithState.Create(node.Type, node.Type?.CanContainNull() != false && node.ConstantValueOpt?.IsNull == true ? NullableFlowState.MaybeDefault : NullableFlowState.NotNull)); 12519node.IsAddition ? GetState(ref this.State, memberSlot).Meet(ResultType.State) : NullableFlowState.MaybeNull); 12636private bool ReportPossibleNullReceiverIfNeeded(TypeSymbol type, NullableFlowState state, bool checkNullableValueType, SyntaxNode syntax, out bool reportedDiagnostic) 12695SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.NotNull)); 12710SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.NotNull)); 12759SetResultType(node, TypeWithState.Create(node.Type, NullableFlowState.NotNull)); 12765SetResultType(node, TypeWithState.Create(type, NullableFlowState.NotNull)); 12833SetState(ref this.State, slot, NullableFlowState.NotNull); 12922Debug.Assert(ResultType is TypeWithState { Type: FunctionPointerTypeSymbol { }, State: NullableFlowState.NotNull }); 13227SetValue(Id, index, useNotNullsAsDefault ? NullableFlowState.NotNull : walker.GetDefaultState(ref this, slot)); 13231public NullableFlowState this[int slot] 13245private NullableFlowState GetValue(int id, int index) 13255private NullableFlowState GetValue(int index) 13259return NullableFlowState.NotNull; 13266var result = (_state[index], _state[index + 1]) switch 13268(false, false) => NullableFlowState.NotNull, // Should not be reachable 13269(true, false) => NullableFlowState.MaybeNull, 13270(false, true) => NullableFlowState.MaybeDefault, 13271(true, true) => NullableFlowState.NotNull 13277private void SetValue(int id, int index, NullableFlowState value) 13290private void SetValue(int index, NullableFlowState value) 13298NullableFlowState.MaybeNull => (true, false), 13299NullableFlowState.MaybeDefault => (false, true), 13300NullableFlowState.NotNull => (true, true), 13354var oldValue = oldReachable ? GetValue(i) : NullableFlowState.NotNull; 13355var newValue = oldValue.Join(other.GetValue(i)); 13380var oldValue = GetValue(i); 13381var newValue = oldValue.Meet(other.GetValue(i)); 13397var mayBeNull = GetValue(i) is NullableFlowState.MaybeNull or NullableFlowState.MaybeDefault; 13428NullableFlowState.MaybeNull => "?", 13429NullableFlowState.MaybeDefault => "??",

481SetState(ref State, outputSlot, NullableFlowState.NotNull); 579SetState(ref this.State, outputSlot, NullableFlowState.NotNull); // Slice value is assumed to be never null 682var tempState = GetState(ref this.State, tempSlot); 958NullableFlowState inferredState; 1008NullableFlowState inferredState = BestTypeInferrer.GetNullableState(resultTypes);

1228static NullableFlowState getTypeArgumentState(in TypeWithAnnotations typeWithAnnotations) 1233return NullableFlowState.NotNull; 1237return type.IsNullableTypeOrTypeParameter() ? NullableFlowState.MaybeNull : NullableFlowState.NotNull; 1242return type.IsTypeParameterDisallowingAnnotationInCSharp8() ? NullableFlowState.MaybeDefault : NullableFlowState.MaybeNull; 1244return NullableFlowState.NotNull; 1249return NullableFlowState.NotNull; 1251NullableFlowState? result = null; 1254var constraintState = getTypeArgumentState(constraintType); 1264return result ?? NullableFlowState.MaybeNull; 1267static bool constraintTypeAllows(in TypeWithAnnotations typeWithAnnotations, NullableFlowState state) 1269if (state == NullableFlowState.NotNull) 1296return state == NullableFlowState.MaybeNull;

104var flowState = TypeWithAnnotations.Create(type, annotation).ToTypeWithState().State;

11/// When in doubt we conservatively use <see cref="NullableFlowState.NotNull"/>

13public static bool MayBeNull(this NullableFlowState state) => state != NullableFlowState.NotNull; 15public static bool IsNotNull(this NullableFlowState state) => state == NullableFlowState.NotNull; 19/// The result is <see cref="NullableFlowState.MaybeNull"/> if either operand is that. 21public static NullableFlowState Join(this NullableFlowState a, NullableFlowState b) => (a > b) ? a : b; 25/// The result is <see cref="NullableFlowState.NotNull"/> if either operand is that. 27public static NullableFlowState Meet(this NullableFlowState a, NullableFlowState b) => (a < b) ? a : b; 29internal static CodeAnalysis.NullableFlowState ToPublicFlowState(this CSharp.NullableFlowState nullableFlowState) => 32CSharp.NullableFlowState.NotNull => CodeAnalysis.NullableFlowState.NotNull, 33CSharp.NullableFlowState.MaybeNull => CodeAnalysis.NullableFlowState.MaybeNull, 34CSharp.NullableFlowState.MaybeDefault => CodeAnalysis.NullableFlowState.MaybeNull, 39public static CSharp.NullableFlowState ToInternalFlowState(this CodeAnalysis.NullableFlowState flowState) => 42CodeAnalysis.NullableFlowState.None => CSharp.NullableFlowState.NotNull, 43CodeAnalysis.NullableFlowState.NotNull => CSharp.NullableFlowState.NotNull, 44CodeAnalysis.NullableFlowState.MaybeNull => CSharp.NullableFlowState.MaybeNull,

813static NullableFlowState getFlowState(TypeSymbol type, NullableAnnotation annotation) 817return annotation.IsAnnotated() ? NullableFlowState.MaybeDefault : NullableFlowState.NotNull; 821return annotation switch { NullableAnnotation.Annotated => NullableFlowState.MaybeDefault, NullableAnnotation.NotAnnotated => NullableFlowState.MaybeNull, _ => NullableFlowState.NotNull }; 825return annotation switch { NullableAnnotation.Annotated => NullableFlowState.MaybeDefault, _ => NullableFlowState.NotNull }; 829return NullableFlowState.MaybeNull; 831return annotation switch { NullableAnnotation.Annotated => NullableFlowState.MaybeNull, _ => NullableFlowState.NotNull };

17public readonly NullableFlowState State; 20public bool MayBeNull => State == NullableFlowState.MaybeNull; 21public bool IsNotNull => State == NullableFlowState.NotNull; 25return Create(type, NullableFlowState.MaybeDefault); 28public static TypeWithState Create(TypeSymbol? type, NullableFlowState defaultState) 30if (defaultState == NullableFlowState.MaybeDefault && 36var state = defaultState != NullableFlowState.NotNull && type?.CanContainNull() != false ? NullableFlowState.MaybeNull : NullableFlowState.NotNull; 45NullableFlowState state; 50state = NullableFlowState.MaybeDefault; 54state = NullableFlowState.NotNull; 63state = NullableFlowState.NotNull; 69private TypeWithState(TypeSymbol? type, NullableFlowState state) 71Debug.Assert(state == NullableFlowState.NotNull || type?.CanContainNull() != false); 72Debug.Assert(state != NullableFlowState.MaybeDefault || type is null || type.IsTypeParameterDisallowingAnnotationInCSharp8()); 81public TypeWithState WithNotNullState() => new TypeWithState(Type, NullableFlowState.NotNull); 83public TypeWithState WithSuppression(bool suppress) => suppress ? new TypeWithState(Type, NullableFlowState.NotNull) : this; 90return (State == NullableFlowState.MaybeDefault || asAnnotatedType) ? type.SetIsAnnotated(compilation) : type;

126877private static readonly NullableFlowState[] s_AllNullableFlowStates = (NullableFlowState[])Enum.GetValues(typeof(NullableFlowState)); 126898var inputs = new[] { NullableFlowState.NotNull, NullableFlowState.MaybeNull }; 126900Func<int, int, NullableFlowState> getResult = (i, j) => inputs[i].Join(inputs[j]); 126902var expected = new NullableFlowState[2, 2] 126904{ NullableFlowState.NotNull, NullableFlowState.MaybeNull }, 126905{ NullableFlowState.MaybeNull, NullableFlowState.MaybeNull }, 126930var inputs = new[] { NullableFlowState.NotNull, NullableFlowState.MaybeNull }; 126931Func<int, int, NullableFlowState> getResult = (i, j) => inputs[i].Meet(inputs[j]); 126933var expected = new NullableFlowState[2, 2] 126935{ NullableFlowState.NotNull, NullableFlowState.NotNull }, 126936{ NullableFlowState.NotNull, NullableFlowState.MaybeNull }, 126963private static void AssertEqual(NullableFlowState[,] expected, Func<int, int, NullableFlowState> getResult, int size) 126965AssertEx.Equal<NullableFlowState>(expected, getResult, (na1, na2) => na1 == na2, na => $"NullableFlowState.{na}", "{0,-32:G}", size); 126984foreach (var a in s_AllNullableFlowStates) 126986foreach (var b in s_AllNullableFlowStates) 127014foreach (var a in s_AllNullableFlowStates) 127016foreach (var b in s_AllNullableFlowStates) 127018foreach (var c in s_AllNullableFlowStates) 127020var leftFirst = a.Join(b).Join(c); 127021var rightFirst = a.Join(b.Join(c)); 127048foreach (var a in s_AllNullableFlowStates) 127050foreach (var b in s_AllNullableFlowStates) 127052foreach (var c in s_AllNullableFlowStates) 127054var leftFirst = a.Meet(b).Meet(c); 127055var rightFirst = a.Meet(b.Meet(c)); 127101foreach (var a in s_AllNullableFlowStates) 127103foreach (var b in s_AllNullableFlowStates) 127105var leftFirst = a.Join(b); 127106var rightFirst = b.Join(a); 127129foreach (var a in s_AllNullableFlowStates) 127131foreach (var b in s_AllNullableFlowStates) 127133var leftFirst = a.Meet(b); 127134var rightFirst = b.Meet(a);