private void BranchToLocation(FlowLocation location, FlowState state)
{
TState existingState;
if (this.joinStates.TryGetValue(location, out existingState))
{
this.joinStates = this.joinStates.SetItem(location, (TState)existingState.Join(this.lexicalState));
}
else
{
this.joinStates = this.joinStates.SetItem(location, this.lexicalState);
}
}
public override void AfterConditional(SyntaxNode node, out FlowState trueState, out FlowState falseState)
{
trueState = this;
falseState = this;
var kind = node.Kind();
if (kind == SyntaxKind.EqualsExpression || kind == SyntaxKind.NotEqualsExpression)
{
var binop = (BinaryExpressionSyntax)node;
ExpressionSyntax influencedExpr = null;
if (binop.Right.IsKind(SyntaxKind.NullLiteralExpression))
{
influencedExpr = this.GetVariableExpression(binop.Left);
}
else if (binop.Left.IsKind(SyntaxKind.NullLiteralExpression))
{
influencedExpr = this.GetVariableExpression(binop.Right);
}
if (influencedExpr != null)
{
if (kind == SyntaxKind.EqualsExpression)
{
trueState = this.WithReferenceState(influencedExpr, NullState.Null);
falseState = this.WithReferenceState(influencedExpr, NullState.NotNull);
}
else
{
trueState = this.WithReferenceState(influencedExpr, NullState.NotNull);
falseState = this.WithReferenceState(influencedExpr, NullState.Null);
}
}
}
}
public override bool Equals(FlowState state)
{
var nfs = state as NullFlowState;
return(nfs != null && nfs.variableStates == this.variableStates);
}