310 references to NullableFlowState
Microsoft.CodeAnalysis.CSharp (268)
Binder\Semantics\BestTypeInferrer.cs (3)
36
public static
NullableFlowState
GetNullableState(ArrayBuilder<TypeWithState> types)
38
NullableFlowState
result =
NullableFlowState
.NotNull;
FlowAnalysis\NullableWalker.cs (193)
145
public VisitResult(TypeSymbol? type, NullableAnnotation annotation,
NullableFlowState
state)
235
private static readonly TypeWithState _invalidType = TypeWithState.Create(new UnsupportedMetadataTypeSymbol(),
NullableFlowState
.NotNull);
819
var
memberState = GetState(ref state, slot);
820
var
badState = symbolType.Type.IsPossiblyNullableReferenceTypeTypeParameter() && (annotations & FlowAnalysisAnnotations.NotNull) == 0
821
?
NullableFlowState
.MaybeDefault
822
:
NullableFlowState
.MaybeNull;
878
SetState(ref this.State, memberSlot, type.Type.IsPossiblyNullableReferenceTypeTypeParameter() ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.MaybeNull);
1173
var
parameterState = GetState(ref state, memberSlot);
1205
SetState(ref this.State, memberSlot,
NullableFlowState
.MaybeNull);
1318
var
parameterState = GetState(ref state, slot);
1374
var
parameterState = GetState(ref stateWhen, slot);
1401
private void EnforceNotNullIfNotNull(SyntaxNode? syntaxOpt, LocalState state, ImmutableArray<ParameterSymbol> parameters, ImmutableHashSet<string> inputParamNames,
NullableFlowState
outputState, ParameterSymbol? outputParam)
1989
private
NullableFlowState
GetState(ref LocalState state, int slot)
1992
return
NullableFlowState
.NotNull;
1998
private void SetState(ref LocalState state, int slot,
NullableFlowState
value, bool useNotNullsAsDefault = false)
2020
private
NullableFlowState
GetDefaultState(ref LocalState state, int slot)
2025
return
NullableFlowState
.NotNull;
2055
return
NullableFlowState
.NotNull;
2384
private static bool ShouldReportNullableAssignment(TypeWithAnnotations type,
NullableFlowState
state)
2401
case
NullableFlowState
.NotNull:
2403
case
NullableFlowState
.MaybeNull:
2479
valueType.State ==
NullableFlowState
.MaybeDefault;
2661
var
newState = valueType.State;
2764
NullableFlowState
value = isDefaultValue ?
NullableFlowState
.MaybeNull : fieldOrPropertyType.ToTypeWithState().State;
2776
NullableFlowState
.NotNull;
2824
/// and the new state is not <see cref="
NullableFlowState
.NotNull"/>, this method should be called to perform the
2828
private void SetStateAndTrackForFinally(ref LocalState state, int slot,
NullableFlowState
newState)
2832
if (newState !=
NullableFlowState
.NotNull && NonMonotonicState.HasValue)
2917
private
NullableFlowState
GetDefaultState(Symbol symbol)
3010
var
state = GetParameterState(parameterType, parameter.FlowAnalysisAnnotations).State;
3048
return TypeWithState.Create(parameterType.Type,
NullableFlowState
.MaybeDefault);
3053
return TypeWithState.Create(parameterType.Type,
NullableFlowState
.NotNull);
3356
SetState(ref state, slot,
NullableFlowState
.NotNull);
3853
SetResultType(node, TypeWithState.Create(null,
NullableFlowState
.NotNull));
3861
SetResultType(node, TypeWithState.Create(null,
NullableFlowState
.NotNull));
4015
NullableFlowState
resultState = getResultState(node, collectionKind);
4021
static
NullableFlowState
getResultState(BoundCollectionExpression node, CollectionExpressionTypeKind collectionKind)
4033
return
NullableFlowState
.NotNull;
4101
(int slot,
NullableFlowState
resultState, Func<TypeSymbol, MethodSymbol?, int>? initialStateInferenceCompletion) =
4121
NullableFlowState
resultState,
4150
NullableFlowState
resultState)
4152
Debug.Assert(resultState ==
NullableFlowState
.NotNull);
4184
(int slot,
NullableFlowState
resultState, Func<TypeSymbol, MethodSymbol?, int>? completion) inferInitialObjectState(
4192
return (-1,
NullableFlowState
.NotNull, inferInitialObjectStateAsContinuation(node, arguments, argumentResults, hasObjectInitializer));
4198
var
resultState =
NullableFlowState
.NotNull;
4230
resultState =
NullableFlowState
.MaybeNull;
4265
Debug.Assert(resultState ==
NullableFlowState
.NotNull);
4399
var result = new VisitResult(objectInitializer.Type, NullableAnnotation.NotAnnotated,
NullableFlowState
.NotNull);
4626
SetAnalyzedNullability(node.ImplicitReceiverOpt, new VisitResult(node.ImplicitReceiverOpt.Type, NullableAnnotation.NotAnnotated,
NullableFlowState
.NotNull));
4684
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.NotNull));
4689
var resultType = TypeWithState.Create(node.Type,
NullableFlowState
.NotNull);
4797
SetResultType(node, TypeWithState.Create(anonymousType,
NullableFlowState
.NotNull));
4829
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.NotNull));
4834
SetResultType(node, TypeWithState.Create(arrayType,
NullableFlowState
.NotNull));
4910
var
elementState = BestTypeInferrer.GetNullableState(expressionTypes);
5112
NullableFlowState
resultState =
NullableFlowState
.NotNull;
5140
resultState =
NullableFlowState
.MaybeNull; // Delegate removal can produce null.
5143
resultState =
NullableFlowState
.NotNull;
5732
SetState(ref stateToUpdate, slot,
NullableFlowState
.NotNull);
5761
SetState(ref state, slot,
NullableFlowState
.NotNull);
5786
if (GetState(ref state, slot) ==
NullableFlowState
.NotNull)
5789
SetState(ref state, slot,
NullableFlowState
.MaybeNull);
5818
SetState(ref state, childSlot,
NullableFlowState
.NotNull);
5897
SetState(ref this.State, leftSlot,
NullableFlowState
.NotNull);
5952
BoundNullCoalescingOperatorResultKind.NoCommonType => (node.Type,
NullableFlowState
.NotNull),
5957
BoundNullCoalescingOperatorResultKind.RightDynamicType => (rightResultType!,
NullableFlowState
.NotNull),
5964
(TypeSymbol ResultType,
NullableFlowState
LeftState) getLeftResultType(TypeSymbol leftType, TypeSymbol rightType)
5974
return (rightType,
NullableFlowState
.NotNull);
5979
return (leftType,
NullableFlowState
.NotNull);
5982
(TypeSymbol ResultType,
NullableFlowState
LeftState) getResultStateWithRightType(TypeSymbol leftType, TypeSymbol rightType)
5994
TypeWithState.Create(leftType,
NullableFlowState
.NotNull),
6005
return (rightType,
NullableFlowState
.NotNull);
6178
SetResultType(node, TypeWithState.Create(resultType,
NullableFlowState
.MaybeDefault));
6233
var
rValueState = consequenceRValue.State.Join(alternativeRValue.State);
6341
NullableFlowState
resultState;
6501
SetResultType(node, TypeWithState.Create(rvalueType,
NullableFlowState
.NotNull));
7012
private
NullableFlowState
LearnFromCompareExchangeMethod(in CompareExchangeInfo compareExchangeInfo)
7032
return
NullableFlowState
.NotNull;
7042
var
valueFlowState = compareExchangeInfo.Results[valueIndex].RValueType.State;
7049
var
locationFlowState = compareExchangeInfo.Results[locationIndex].RValueType.State;
7166
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.NotNull);
7171
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.MaybeDefault);
7756
SetState(ref state, memberSlot,
NullableFlowState
.NotNull);
8061
var
adjustedState = LearnFromCompareExchangeMethod(in compareExchangeInfoOpt);
8185
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.MaybeDefault);
8191
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.NotNull);
8206
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.MaybeDefault);
8210
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.NotNull);
8225
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.MaybeDefault);
8229
return TypeWithState.Create(typeWithState.Type,
NullableFlowState
.NotNull);
8787
NullableFlowState
state = GetState(ref this.State, slot);
9062
SetResultType(node, TypeWithState.Create(null,
NullableFlowState
.NotNull));
9069
SetState(ref this.State, slot,
NullableFlowState
.NotNull);
9087
SetResultType(node, TypeWithState.Create(tupleOpt,
NullableFlowState
.NotNull));
9209
SetState(ref this.State, targetFieldSlot,
NullableFlowState
.NotNull);
9226
SetState(ref this.State, targetFieldSlot,
NullableFlowState
.NotNull);
9462
NullableFlowState
resultState =
NullableFlowState
.NotNull;
9494
resultState =
NullableFlowState
.NotNull;
9518
return TypeWithState.Create(targetType,
NullableFlowState
.NotNull);
9524
resultState =
NullableFlowState
.NotNull;
9528
resultState =
NullableFlowState
.NotNull;
9533
resultState =
NullableFlowState
.NotNull;
9573
resultState =
NullableFlowState
.NotNull;
9697
resultState =
NullableFlowState
.NotNull;
9767
static TypeWithState calculateResultType(TypeWithAnnotations targetTypeWithNullability, bool fromExplicitCast,
NullableFlowState
resultState, bool isSuppressed, TypeSymbol targetType)
9771
resultState =
NullableFlowState
.NotNull;
9776
resultState = targetType?.IsTypeParameterDisallowingAnnotationInCSharp8() == true ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.MaybeNull;
9783
static
NullableFlowState
getReferenceConversionResultState(TypeWithAnnotations targetType, TypeWithState operandType)
9785
var
state = operandType.State;
9788
case
NullableFlowState
.MaybeNull:
9794
return
NullableFlowState
.MaybeDefault;
9800
return (annotation == NullableAnnotation.Annotated) ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.MaybeNull;
9804
case
NullableFlowState
.MaybeDefault:
9807
return
NullableFlowState
.MaybeNull;
9817
static
NullableFlowState
getBoxingConversionResultState(TypeWithAnnotations targetType, TypeWithState operandType)
9819
var
state = operandType.State;
9820
if (state ==
NullableFlowState
.MaybeNull)
9825
return
NullableFlowState
.MaybeDefault;
9835
return (annotation == NullableAnnotation.Annotated) ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.MaybeNull;
9845
static
NullableFlowState
getUnboxingConversionResultState(TypeWithState operandType)
9847
var
state = operandType.State;
9848
if (state ==
NullableFlowState
.MaybeNull)
9850
return
NullableFlowState
.MaybeDefault;
9855
static
NullableFlowState
getConversionResultState(TypeWithState operandType)
9857
var
state = operandType.State;
9858
if (state ==
NullableFlowState
.MaybeNull)
9860
return
NullableFlowState
.MaybeDefault;
9996
var resultType = TypeWithState.Create(targetType,
NullableFlowState
.NotNull);
10039
NullableFlowState
operandState = operandType.State;
10159
private TypeWithState GetLiftedReturnType(TypeWithAnnotations returnType,
NullableFlowState
operandState)
10163
NullableFlowState
state = returnType.ToTypeWithState().State.Join(operandState);
10180
private TypeWithState GetLiftedReturnTypeIfNecessary(bool isLifted, TypeWithAnnotations returnType,
NullableFlowState
operandState)
10276
var result = TypeWithState.Create(delegateType,
NullableFlowState
.NotNull);
10573
var rvalueResult = TypeWithState.Create(node.Type,
NullableFlowState
.NotNull);
10991
var valueBeforeNullableWrapping = TypeWithState.Create(underlyingType.Type,
NullableFlowState
.NotNull);
11120
SetResultType(node, TypeWithState.Create(receiverType.Type,
NullableFlowState
.NotNull));
11144
SetResultType(node, TypeWithState.Create(opType.Type,
NullableFlowState
.NotNull));
11297
SetResultType(node, TypeWithState.Create(receiverType.Type,
NullableFlowState
.NotNull));
11325
SetResultType(node, TypeWithState.Create(opType.Type,
NullableFlowState
.NotNull));
11627
var
state = GetState(ref this.State, slot);
11639
SetState(ref this.StateWhenTrue, containingSlot,
NullableFlowState
.NotNull);
11860
if (enumeratorReturnType.State !=
NullableFlowState
.NotNull)
11941
var
state =
NullableFlowState
.NotNull;
12145
TypeWithState.Create(node.Type, node.OperatorKind.IsLifted() ? argumentResult.State :
NullableFlowState
.NotNull);
12413
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.NotNull));
12435
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.MaybeDefault));
12450
SetState(ref this.State, slot,
NullableFlowState
.NotNull);
12496
NullableFlowState
resultState =
NullableFlowState
.NotNull;
12511
resultState =
NullableFlowState
.MaybeDefault;
12549
SetResultType(node, TypeWithState.Create(node.Type, node.Type?.CanContainNull() != false && node.ConstantValueOpt?.IsNull == true ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.NotNull));
12657
node.IsAddition ? GetState(ref this.State, memberSlot).Meet(ResultType.State) :
NullableFlowState
.MaybeNull);
12774
private bool ReportPossibleNullReceiverIfNeeded(TypeSymbol type,
NullableFlowState
state, bool checkNullableValueType, SyntaxNode syntax, out bool reportedDiagnostic)
12833
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.NotNull));
12848
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.NotNull));
12897
SetResultType(node, TypeWithState.Create(node.Type,
NullableFlowState
.NotNull));
12903
SetResultType(node, TypeWithState.Create(type,
NullableFlowState
.NotNull));
12971
SetState(ref this.State, slot,
NullableFlowState
.NotNull);
13062
Debug.Assert(ResultType is TypeWithState { Type: FunctionPointerTypeSymbol { }, State:
NullableFlowState
.NotNull });
13367
SetValue(Id, index, useNotNullsAsDefault ?
NullableFlowState
.NotNull : walker.GetDefaultState(ref this, slot));
13371
public
NullableFlowState
this[int slot]
13385
private
NullableFlowState
GetValue(int id, int index)
13395
private
NullableFlowState
GetValue(int index)
13399
return
NullableFlowState
.NotNull;
13406
var
result = (_state[index], _state[index + 1]) switch
13408
(false, false) =>
NullableFlowState
.NotNull, // Should not be reachable
13409
(true, false) =>
NullableFlowState
.MaybeNull,
13410
(false, true) =>
NullableFlowState
.MaybeDefault,
13411
(true, true) =>
NullableFlowState
.NotNull
13417
private void SetValue(int id, int index,
NullableFlowState
value)
13430
private void SetValue(int index,
NullableFlowState
value)
13438
NullableFlowState
.MaybeNull => (true, false),
13439
NullableFlowState
.MaybeDefault => (false, true),
13440
NullableFlowState
.NotNull => (true, true),
13494
var
oldValue = oldReachable ? GetValue(i) :
NullableFlowState
.NotNull;
13495
var
newValue = oldValue.Join(other.GetValue(i));
13520
var
oldValue = GetValue(i);
13521
var
newValue = oldValue.Meet(other.GetValue(i));
13537
var mayBeNull = GetValue(i) is
NullableFlowState
.MaybeNull or
NullableFlowState
.MaybeDefault;
13568
NullableFlowState
.MaybeNull => "?",
13569
NullableFlowState
.MaybeDefault => "??",
FlowAnalysis\NullableWalker_Patterns.cs (5)
481
SetState(ref State, outputSlot,
NullableFlowState
.NotNull);
579
SetState(ref this.State, outputSlot,
NullableFlowState
.NotNull); // Slice value is assumed to be never null
682
var
tempState = GetState(ref this.State, tempSlot);
958
NullableFlowState
inferredState;
1008
NullableFlowState
inferredState = BestTypeInferrer.GetNullableState(resultTypes);
Symbols\ConstraintsHelper.cs (14)
1226
static
NullableFlowState
getTypeArgumentState(in TypeWithAnnotations typeWithAnnotations)
1231
return
NullableFlowState
.NotNull;
1235
return type.IsNullableTypeOrTypeParameter() ?
NullableFlowState
.MaybeNull :
NullableFlowState
.NotNull;
1240
return type.IsTypeParameterDisallowingAnnotationInCSharp8() ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.MaybeNull;
1242
return
NullableFlowState
.NotNull;
1247
return
NullableFlowState
.NotNull;
1249
NullableFlowState
? result = null;
1252
var
constraintState = getTypeArgumentState(constraintType);
1262
return result ??
NullableFlowState
.MaybeNull;
1265
static bool constraintTypeAllows(in TypeWithAnnotations typeWithAnnotations,
NullableFlowState
state)
1267
if (state ==
NullableFlowState
.NotNull)
1294
return state ==
NullableFlowState
.MaybeNull;
Symbols\NullableAnnotationExtensions.cs (1)
104
var
flowState = TypeWithAnnotations.Create(type, annotation).ToTypeWithState().State;
Symbols\NullableFlowState.cs (1)
11
/// When in doubt we conservatively use <see cref="
NullableFlowState
.NotNull"/>
Symbols\NullableFlowStateExtensions.cs (20)
13
public static bool MayBeNull(this
NullableFlowState
state) => state !=
NullableFlowState
.NotNull;
15
public static bool IsNotNull(this
NullableFlowState
state) => state ==
NullableFlowState
.NotNull;
19
/// The result is <see cref="
NullableFlowState
.MaybeNull"/> if either operand is that.
21
public 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.
27
public static
NullableFlowState
Meet(this
NullableFlowState
a,
NullableFlowState
b) => (a < b) ? a : b;
29
internal static CodeAnalysis.NullableFlowState ToPublicFlowState(this CSharp.
NullableFlowState
nullableFlowState) =>
32
CSharp.
NullableFlowState
.NotNull => CodeAnalysis.NullableFlowState.NotNull,
33
CSharp.
NullableFlowState
.MaybeNull => CodeAnalysis.NullableFlowState.MaybeNull,
34
CSharp.
NullableFlowState
.MaybeDefault => CodeAnalysis.NullableFlowState.MaybeNull,
39
public static CSharp.
NullableFlowState
ToInternalFlowState(this CodeAnalysis.NullableFlowState flowState) =>
42
CodeAnalysis.NullableFlowState.None => CSharp.
NullableFlowState
.NotNull,
43
CodeAnalysis.NullableFlowState.NotNull => CSharp.
NullableFlowState
.NotNull,
44
CodeAnalysis.NullableFlowState.MaybeNull => CSharp.
NullableFlowState
.MaybeNull,
Symbols\TypeWithAnnotations.cs (11)
813
static
NullableFlowState
getFlowState(TypeSymbol type, NullableAnnotation annotation)
817
return annotation.IsAnnotated() ?
NullableFlowState
.MaybeDefault :
NullableFlowState
.NotNull;
821
return annotation switch { NullableAnnotation.Annotated =>
NullableFlowState
.MaybeDefault, NullableAnnotation.NotAnnotated =>
NullableFlowState
.MaybeNull, _ =>
NullableFlowState
.NotNull };
825
return annotation switch { NullableAnnotation.Annotated =>
NullableFlowState
.MaybeDefault, _ =>
NullableFlowState
.NotNull };
829
return
NullableFlowState
.MaybeNull;
831
return annotation switch { NullableAnnotation.Annotated =>
NullableFlowState
.MaybeNull, _ =>
NullableFlowState
.NotNull };
Symbols\TypeWithState.cs (20)
17
public readonly
NullableFlowState
State;
20
public bool MayBeNull => State ==
NullableFlowState
.MaybeNull;
21
public bool IsNotNull => State ==
NullableFlowState
.NotNull;
25
return Create(type,
NullableFlowState
.MaybeDefault);
28
public static TypeWithState Create(TypeSymbol? type,
NullableFlowState
defaultState)
30
if (defaultState ==
NullableFlowState
.MaybeDefault &&
36
var
state = defaultState !=
NullableFlowState
.NotNull && type?.CanContainNull() != false ?
NullableFlowState
.MaybeNull :
NullableFlowState
.NotNull;
45
NullableFlowState
state;
50
state =
NullableFlowState
.MaybeDefault;
54
state =
NullableFlowState
.NotNull;
63
state =
NullableFlowState
.NotNull;
69
private TypeWithState(TypeSymbol? type,
NullableFlowState
state)
71
Debug.Assert(state ==
NullableFlowState
.NotNull || type?.CanContainNull() != false);
72
Debug.Assert(state !=
NullableFlowState
.MaybeDefault || type is null || type.IsTypeParameterDisallowingAnnotationInCSharp8());
81
public TypeWithState WithNotNullState() => new TypeWithState(Type,
NullableFlowState
.NotNull);
83
public TypeWithState WithSuppression(bool suppress) => suppress ? new TypeWithState(Type,
NullableFlowState
.NotNull) : this;
90
return (State ==
NullableFlowState
.MaybeDefault || asAnnotatedType) ? type.SetIsAnnotated(compilation) : type;
Microsoft.CodeAnalysis.CSharp.Semantic.UnitTests (42)
Semantics\NullableReferenceTypesTests.cs (42)
126961
private static readonly
NullableFlowState
[] s_AllNullableFlowStates = (
NullableFlowState
[])Enum.GetValues(typeof(
NullableFlowState
));
126982
var inputs = new[] {
NullableFlowState
.NotNull,
NullableFlowState
.MaybeNull };
126984
Func<int, int,
NullableFlowState
> getResult = (i, j) => inputs[i].Join(inputs[j]);
126986
var expected = new
NullableFlowState
[2, 2]
126988
{
NullableFlowState
.NotNull,
NullableFlowState
.MaybeNull },
126989
{
NullableFlowState
.MaybeNull,
NullableFlowState
.MaybeNull },
127014
var inputs = new[] {
NullableFlowState
.NotNull,
NullableFlowState
.MaybeNull };
127015
Func<int, int,
NullableFlowState
> getResult = (i, j) => inputs[i].Meet(inputs[j]);
127017
var expected = new
NullableFlowState
[2, 2]
127019
{
NullableFlowState
.NotNull,
NullableFlowState
.NotNull },
127020
{
NullableFlowState
.NotNull,
NullableFlowState
.MaybeNull },
127047
private static void AssertEqual(
NullableFlowState
[,] expected, Func<int, int,
NullableFlowState
> getResult, int size)
127049
AssertEx.Equal<
NullableFlowState
>(expected, getResult, (na1, na2) => na1 == na2, na => $"NullableFlowState.{na}", "{0,-32:G}", size);
127068
foreach (
var
a in s_AllNullableFlowStates)
127070
foreach (
var
b in s_AllNullableFlowStates)
127098
foreach (
var
a in s_AllNullableFlowStates)
127100
foreach (
var
b in s_AllNullableFlowStates)
127102
foreach (
var
c in s_AllNullableFlowStates)
127104
var
leftFirst = a.Join(b).Join(c);
127105
var
rightFirst = a.Join(b.Join(c));
127132
foreach (
var
a in s_AllNullableFlowStates)
127134
foreach (
var
b in s_AllNullableFlowStates)
127136
foreach (
var
c in s_AllNullableFlowStates)
127138
var
leftFirst = a.Meet(b).Meet(c);
127139
var
rightFirst = a.Meet(b.Meet(c));
127185
foreach (
var
a in s_AllNullableFlowStates)
127187
foreach (
var
b in s_AllNullableFlowStates)
127189
var
leftFirst = a.Join(b);
127190
var
rightFirst = b.Join(a);
127213
foreach (
var
a in s_AllNullableFlowStates)
127215
foreach (
var
b in s_AllNullableFlowStates)
127217
var
leftFirst = a.Meet(b);
127218
var
rightFirst = b.Meet(a);