Use Environment.NewLine instead of hard-coded linefeed in ParseError.ToString (#11746)

src/System.Management.Automation/engine/parser/Parser.cs

@@ -8059,7 +8059,7 @@ namespace System.Management.Automation.Language
         /// <returns></returns>
         public override string ToString()
         {
-            return PositionUtilities.VerboseMessage(Extent) + "\n" + Message;
+            return PositionUtilities.VerboseMessage(Extent) + Environment.NewLine + Message;
         }
 
         /// <summary>

test/powershell/Language/Parser/Parsing.Tests.ps1

@@ -459,3 +459,23 @@ Describe "Ternary Operator parsing" -Tags CI {
         $expr.IfFalse | Should -BeOfType System.Management.Automation.Language.ConstantExpressionAst
     }
 }
+
+Describe "ParserError type tests" -Tag CI {
+    # This test was added because there use to be a hardcoded newline in the ToString() method of
+    # the ParseError class. This makes sure the proper newlines are used.
+    It "Should use consistant newline depending on OS" {
+        $ers = $null
+        [System.Management.Automation.Language.Parser]::ParseInput('$x =', [ref]$null, [ref]$ers) | Out-Null
+        $measureResult = $ers[0].ToString() -split [System.Environment]::NewLine | Measure-Object
+
+        # We expect the string to have 4 lines. That means that if we split by NewLine for that platform,
+        # We should have 4 as the count.
+        $measureResult.Count | Should -BeExactly 4
+
+        # Just checking the above is not enough. We should also make sure that on non-Windows, there are no
+        # `r`n
+        if (!$IsWindows) {
+            $measureResult = $ers[0].ToString() | Should -Not -Contain "`r`n"
+        }
+    }
+}