From 9e428fe75443bded413b9e966423ab15c716d789 Mon Sep 17 00:00:00 2001
From: Martin Strecker <Martin.Strecker@web.de>
Date: Wed, 23 Jun 2021 19:00:27 +0100
Subject: [PATCH] Use WithTriviaFrom(currentAssignment) and add tests

---
 .../UseCompoundAssignmentTests.cs             | 30 +++++++++++++++++++
 ...actUseCompoundAssignmentCodeFixProvider.cs |  4 +--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/Analyzers/CSharp/Tests/UseCompoundAssignment/UseCompoundAssignmentTests.cs b/src/Analyzers/CSharp/Tests/UseCompoundAssignment/UseCompoundAssignmentTests.cs
index a270cf16619fd..e19e878e0a740 100644
--- a/src/Analyzers/CSharp/Tests/UseCompoundAssignment/UseCompoundAssignmentTests.cs
+++ b/src/Analyzers/CSharp/Tests/UseCompoundAssignment/UseCompoundAssignmentTests.cs
@@ -1160,6 +1160,36 @@ int M(int i)
     }}
 }}",
 @$"public class C
+{{
+    int M(int i)
+    {{
+        {after}
+    }}
+}}");
+        }
+
+        [WorkItem(38054, "https://github.com/dotnet/roslyn/issues/53969")]
+        [Theory, Trait(Traits.Feature, Traits.Features.CodeActionsUseCompoundAssignment)]
+        [InlineData(
+            "/* Before */ i [||]= i + 1; /* After */",
+            "/* Before */ i++; /* After */")]
+        [InlineData(
+            "M( /* Before */ i [||]= i + 1 /* After */ );",
+            "M( /* Before */ ++i /* After */ );")]
+        [InlineData(
+            "M( /* Before */ i [||]= i - 1 /* After */ );",
+            "M( /* Before */ --i /* After */ );")]
+        public async Task TestTriviaPreserved(string before, string after)
+        {
+            await TestInRegularAndScript1Async(
+@$"public class C
+{{
+    int M(int i)
+    {{
+        {before}
+    }}
+}}",
+@$"public class C
 {{
     int M(int i)
     {{
diff --git a/src/Analyzers/Core/CodeFixes/UseCompoundAssignment/AbstractUseCompoundAssignmentCodeFixProvider.cs b/src/Analyzers/Core/CodeFixes/UseCompoundAssignment/AbstractUseCompoundAssignmentCodeFixProvider.cs
index 1784cf7dae4d6..3c6ec77d4ff6d 100644
--- a/src/Analyzers/Core/CodeFixes/UseCompoundAssignment/AbstractUseCompoundAssignmentCodeFixProvider.cs
+++ b/src/Analyzers/Core/CodeFixes/UseCompoundAssignment/AbstractUseCompoundAssignmentCodeFixProvider.cs
@@ -81,12 +81,12 @@ protected override Task FixAllAsync(
 
                         if (diagnostic.Properties.ContainsKey(UseCompoundAssignmentUtilities.Increment))
                         {
-                            return Increment((TExpressionSyntax)leftOfAssign.WithoutTrailingTrivia(), postfix: syntaxFacts.IsSimpleAssignmentStatement(currentAssignment.Parent));
+                            return Increment((TExpressionSyntax)leftOfAssign.WithTriviaFrom(currentAssignment), postfix: syntaxFacts.IsSimpleAssignmentStatement(currentAssignment.Parent));
                         }
 
                         if (diagnostic.Properties.ContainsKey(UseCompoundAssignmentUtilities.Decrement))
                         {
-                            return Decrement((TExpressionSyntax)leftOfAssign.WithoutTrailingTrivia(), postfix: syntaxFacts.IsSimpleAssignmentStatement(currentAssignment.Parent));
+                            return Decrement((TExpressionSyntax)leftOfAssign.WithTriviaFrom(currentAssignment), postfix: syntaxFacts.IsSimpleAssignmentStatement(currentAssignment.Parent));
                         }
 
                         var assignmentOpKind = _binaryToAssignmentMap[syntaxKinds.Convert<TSyntaxKind>(rightOfAssign.RawKind)];