don't suggest fields that are already specified (#2240)

Fixes #2126

Author: jas-valgotar

src/libraries/Microsoft.PowerFx.Core/Texl/Intellisense/SuggestionHandlers/FunctionRecordNameSuggestionHandler.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.PowerFx.Core.Binding.BindInfo;
 using Microsoft.PowerFx.Core.Functions;
@@ -152,9 +153,17 @@ private static bool TryGetParentRecordFieldType(DType aggregateType, TexlNode cu
             internal static bool AddAggregateSuggestions(DType aggregateType, IntellisenseData.IntellisenseData intellisenseData, int cursorPos)
             {
                 var suggestionsAdded = false;
+                var parentRecordNode = intellisenseData.CurNode.Parent as RecordNode;
+                var alreadyUsedFields = parentRecordNode?.Ids.Select(id => id.Name).ToImmutableHashSet() ?? Enumerable.Empty<DName>().ToImmutableHashSet();
                 foreach (var tName in aggregateType.GetNames(DPath.Root).Where(param => !param.Type.IsError))
                 {
                     var usedName = tName.Name;
+
+                    if (alreadyUsedFields.Contains(usedName))
+                    {
+                        continue;
+                    }
+
                     if (DType.TryGetDisplayNameForColumn(aggregateType, usedName, out var maybeDisplayName))
                     {
                         usedName = new DName(maybeDisplayName);

src/tests/Microsoft.PowerFx.Core.Tests/IntellisenseTests/SuggestTest.cs

@@ -168,8 +168,8 @@ private string[] SuggestStrings(string expression, PowerFxConfig config, Culture
         [InlineData("[@In|]", "ErrorKind")]
 
         // FunctionRecordNameSuggestionHandler
-        [InlineData("Error({Kin|d:0})", "Kind:")]
-        [InlineData("Error({|Kind:0, Test:\"\"})", "Kind:", "Test:")]
+        [InlineData("Error({Kin|d:0})")]
+        [InlineData("Error({|Kind:0, Test:\"\"})")]
 
         // ErrorNodeSuggestionHandler
         [InlineData("ForAll([0],`|", "ThisRecord", "Value")]
@@ -493,7 +493,7 @@ public void SuggestUser(string expression, params string[] expected)
         [Theory]
         [InlineData("{|", "output1:", "output2:")]
 
-        [InlineData("{output1: 1, |", "output1:", "output2:")]
+        [InlineData("{output1: 1, |", "output2:")]
 
         // We do not suggest nested type, as this can explode if type is DV.
         [InlineData("{output1: {|")]

src/tests/Microsoft.PowerFx.Interpreter.Tests/InterpreterSuggestTests.cs

@@ -274,21 +274,42 @@ public void TestArgSuggestion(string expression, params string[] expectedSuggest
             "field1:")]
         [InlineData(
             "RecordInputTest( {field1 : 1}, \"test\", {|",
-            "id:", 
+            "id:",
+            "name:")]
+
+        // do not repeat already used fields.
+        [InlineData(
+            "RecordInputTest( {field1 : 2}, \"test\", { id: 1, |",
             "name:")]
+
+        [InlineData(
+            "RecordInputTest( {field1 : 2}, \"test\", { name: \"test\", |",
+            "id:")]
+
         [InlineData(
-            "RecordInputTest( {field1 : 2}, \"test\", { id: 1, name: \"test\"}, {|", 
+            "RecordInputTest( {field1 : 2}, \"test\", { id: 1, name:\"test name\", |}")]
+
+        [InlineData(
+            "RecordInputTest( {field1 : 2}, \"test\", { id: 1, name: \"test\"}, {|",
             "nested:",
             "nested2:")]
 
         // nested record field.
         [InlineData(
-            "RecordInputTest( {field1 : 3}, \"test\", { id: 1, name: \"test\"}, { nested:{|", 
+            "RecordInputTest( {field1 : 3}, \"test\", { id: 1, name: \"test\"}, { nested:{|",
             "field1:")]
         [InlineData(
-            "RecordInputTest( {field1 : 4}, \"test\", { id: 1, name: \"test\"}, { nested2:{|", 
-            "id:", 
+            "RecordInputTest( {field1 : 4}, \"test\", { id: 1, name: \"test\"}, { nested2:{|",
+            "id:",
             "name:")]
+
+        // do not repeat already used fields.
+        [InlineData(
+            "RecordInputTest( {field1 : 4}, \"test\", { id: 1, name: \"test\"}, { nested2:{ id: 2, |",
+            "name:")]
+        [InlineData(
+            "RecordInputTest( {field1 : 4}, \"test\", { id: 1, name: \"test\"}, { nested2:{ id: 2, name: \"test\", |")]
+
         [InlineData(
             "RecordInputTest( {field1 : 3}, \"test\", { id: 1, name: \"test\"}, { nested:{ field1: 1}, nested2: {|",
             "id:",