Add property assignment completion for enums (PowerShell#19178)

* Add property assignment completion for enums

* Move method

Author: MartinGC94

src/System.Management.Automation/engine/CommandCompletion/CompletionAnalysis.cs

@@ -1421,6 +1421,24 @@ private static bool TryGetTypeConstraintOnVariable(
             return typeConstraint != null || setConstraint != null;
         }
 
+        private static List<CompletionResult> CompletePropertyAssignment(MemberExpressionAst memberExpression, CompletionContext context)
+        {
+            if (SafeExprEvaluator.TrySafeEval(memberExpression, context.ExecutionContext, out var evalValue))
+            {
+                if (evalValue is null)
+                {
+                    return null;
+                }
+
+                Type type = evalValue.GetType();
+                if (type.IsEnum)
+                {
+                    return GetResultForEnum(type, context);
+                }
+            }
+            return null;
+        }
+
         private static bool TryGetCompletionsForVariableAssignment(
             CompletionContext completionContext,
             AssignmentStatementAst assignmentAst,
@@ -1452,6 +1470,12 @@ bool TryGetResultForSet(Type typeConstraint, ValidateSetAttribute setConstraint,
                 return false;
             }
 
+            if (assignmentAst.Left is MemberExpressionAst member)
+            {
+                completions = CompletePropertyAssignment(member, completionContext);
+                return completions is not null;
+            }
+
             completions = null;
 
             // Try to get the variable from the assignment, plus any type constraint on it

test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1

@@ -378,6 +378,11 @@ using `
         $res.CompletionMatches[0].CompletionText | Should -BeExactly '${PSVersionTable}'
     }
 
+    It 'Should work for property assignment of enum type:' {
+        $res = TabExpansion2 -inputScript '$psstyle.Progress.View="Clas'
+        $res.CompletionMatches[0].CompletionText | Should -Be '"Classic"'
+    }
+
     It 'Should work for variable assignment of enum type: <inputStr>' -TestCases @(
         @{ inputStr = '$ErrorActionPreference = '; filter = ''; doubleQuotes = $false }
         @{ inputStr = '$ErrorActionPreference='; filter = ''; doubleQuotes = $false }