Fix UseDeclaredVarsMoreThanAssignments being raised for setting properties

Author: quoctruong

Rules/UseDeclaredVarsMoreThanAssignments.cs

@@ -49,11 +49,12 @@ public IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string fileName)
             {
                 foreach (AssignmentStatementAst assignmentAst in assignmentAsts)
                 {
-                    assingmentVarAsts = assignmentAst.Left.FindAll(testAst => testAst is VariableExpressionAst, true); ;
+                    // Only checks for the case where lhs is a variable. Ignore things like $foo.property
+                    VariableExpressionAst assignmentVarAst = assignmentAst.Left as VariableExpressionAst;
 
-                    foreach (VariableExpressionAst assignmentVarAst in assingmentVarAsts)
+                    if (assignmentVarAst != null)
                     {
-                         //Ignore if variable is global or environment variable
+                        //Ignore if variable is global or environment variable
                         if (!Helper.Instance.IsVariableGlobalOrEnvironment(assignmentVarAst, ast)
                             && !assignmentVarAst.VariablePath.IsScript)
                         {

Tests/Rules/UseDeclaredVarsMoreThanAssignmentsNoViolations.ps1

@@ -1,3 +1,4 @@
 $declaredVars = "Declared Vars"
 Write-Ouput $declaredVars
-$script:thisshouldnotraiseerrors = "this should not raise errors"
+$script:thisshouldnotraiseerrors = "this should not raise errors"
+$foo.property = "This also should not raise errors"