public static ImplicitSingleStatementBranches TryGetIfStatementBranches_OverwritePrev(IfStatementSyntax syntax, ISemanticModel model, Assumptions assume)
{
var trueAction = syntax.Statement.CollapsedStatements().SingleOrDefaultAllowMany();
if (trueAction == null) return null;
if (syntax.Else != null) return null;
var prev = syntax.TryGetPrevStatement();
if (prev == null) return null;
if (trueAction.EffectsOverwriteEffectsOf(prev, model, assume) != true) return null;
return new ImplicitSingleStatementBranches(trueAction, prev, prev);
}