Correct casing of parameters as well in PSUseCorrectCasing formatter rule

RuleDocumentation/UseCorrectCasing.md

@@ -4,24 +4,22 @@
 
 ## Description
 
-This is a style/formatting rule. PowerShell is case insensitive where applicable. The casing of cmdlet names does not matter but this rule ensures that the casing matches for consistency and also because most cmdlets start with an upper case and using that improves readability to the human eye.
+This is a style/formatting rule. PowerShell is case insensitive where applicable. The casing of cmdlet names or parameters does not matter but this rule ensures that the casing matches for consistency and also because most cmdlets/parameters start with an upper case and using that improves readability to the human eye.
 
 ## How
 
-Use exact casing of the cmdlet, e.g. `Invoke-Command`.
+Use exact casing of the cmdlet and its parameters, e.g. `Invoke-Command { 'foo' } -RunAsAdministrator`.
 
 ## Example
 
 ### Wrong
 
 ``` PowerShell
-invoke-command { 'foo' }
-}
+invoke-command { 'foo' } -runasadministrator
 ```
 
 ### Correct
 
 ``` PowerShell
-Invoke-Command { 'foo' }
-}
+Invoke-Command { 'foo' } -RunAsAdministrator
 ```

Rules/Strings.resx

@@ -1081,13 +1081,13 @@
     <value>Use space before pipe.</value>
   </data>
   <data name="UseCorrectCasingCommonName" xml:space="preserve">
-    <value>Use exact casing of cmdlet/function name.</value>
+    <value>Use exact casing of cmdlet/function/parameter name.</value>
   </data>
   <data name="UseCorrectCasingDescription" xml:space="preserve">
-    <value>For better readability and consistency, use the exact casing of the cmdlet/function.</value>
+    <value>For better readability and consistency, use the exact casing of the cmdlet/function/parameter.</value>
   </data>
   <data name="UseCorrectCasingError" xml:space="preserve">
-    <value>Cmdlet/Function does not match its exact casing '{0}'.</value>
+    <value>Cmdlet/Function/Parameter does not match its exact casing '{0}'.</value>
   </data>
   <data name="UseCorrectCasingName" xml:space="preserve">
     <value>UseCorrectCasing</value>

Rules/UseCorrectCasing.cs

@@ -6,8 +6,7 @@
 using System.Management.Automation.Language;
 using Microsoft.Windows.PowerShell.ScriptAnalyzer.Generic;
 using System.Management.Automation;
-using System.IO;
-using System.Runtime.InteropServices;
+using System.Linq;
 #if !CORECLR
 using System.ComponentModel.Composition;
 #endif
@@ -67,6 +66,30 @@ public override IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string file
                         commandName,
                         suggestedCorrections: GetCorrectionExtent(commandAst, correctlyCasedCommandName));
                 }
+
+                var commandParameterAsts = commandAst.FindAll(
+                    testAst => testAst is CommandParameterAst, true).Cast<CommandParameterAst>();
+                var availableParameters = commandInfo.Parameters;
+                foreach (var commandParameterAst in commandParameterAsts)
+                {
+                    var parameterName = commandParameterAst.ParameterName;
+                    var parameterMetaData = availableParameters[parameterName];
+                    if (parameterMetaData != null)
+                    {
+                        var correctlyCasedParameterName = parameterMetaData.Name;
+                        if (!parameterName.Equals(correctlyCasedParameterName, StringComparison.Ordinal))
+                        {
+                            yield return new DiagnosticRecord(
+                                string.Format(CultureInfo.CurrentCulture, Strings.UseCorrectCasingError, commandName, parameterName),
+                                GetCommandExtent(commandAst),
+                                GetName(),
+                                DiagnosticSeverity.Warning,
+                                fileName,
+                                commandName,
+                                suggestedCorrections: GetCorrectionExtent(commandParameterAst, correctlyCasedParameterName));
+                        }
+                    }
+                }
             }
         }
 
@@ -109,6 +132,27 @@ private IEnumerable<CorrectionExtent> GetCorrectionExtent(CommandAst commandAst,
             yield return correction;
         }
 
+        private IEnumerable<CorrectionExtent> GetCorrectionExtent(CommandParameterAst commandParameterAst, string correctlyCaseName)
+        {
+            var description = string.Format(
+                CultureInfo.CurrentCulture,
+                Strings.UseCorrectCasingDescription,
+                correctlyCaseName,
+                correctlyCaseName);
+            var cmdExtent = commandParameterAst.Extent;
+            var correction = new CorrectionExtent(
+                cmdExtent.StartLineNumber,
+                cmdExtent.EndLineNumber,
+                // +1 because of the dash before the parameter name
+                cmdExtent.StartColumnNumber + 1,
+                // do not use EndColumnNumber property as it would not cover the case where the colon syntax: -ParameterName:$ParameterValue
+                cmdExtent.StartColumnNumber + 1 + commandParameterAst.ParameterName.Length,
+                correctlyCaseName,
+                commandParameterAst.Extent.File,
+                description);
+            yield return correction;
+        }
+
         /// <summary>
         /// GetName: Retrieves the name of this rule.
         /// </summary>

Tests/Rules/UseCorrectCasing.tests.ps1

@@ -54,4 +54,15 @@ Describe "UseCorrectCasing" {
         $scriptDefinition = ". $uncPath"
         Invoke-Formatter $scriptDefinition | Should -Be $scriptDefinition
     }
+
+    It "Corrects parameter casing" {
+        function Invoke-DummyFunction ($ParameterName) { }
+
+        Invoke-Formatter 'Invoke-DummyFunction -parametername $parameterValue' |
+            Should -Be 'Invoke-DummyFunction -ParameterName $parameterValue'
+        Invoke-Formatter 'Invoke-DummyFunction -parametername:$parameterValue' |
+            Should -Be 'Invoke-DummyFunction -ParameterName:$parameterValue'
+        Invoke-Formatter 'Invoke-DummyFunction -parametername: $parameterValue' |
+            Should -Be 'Invoke-DummyFunction -ParameterName: $parameterValue'
+    }
 }