From e28fb1d87f4b96927632e096202d9b4ea31a306a Mon Sep 17 00:00:00 2001
From: Bela VanderVoort <bela.vandervoort@optimizely.com>
Date: Fri, 17 May 2024 12:39:46 -0500
Subject: [PATCH] Pull trailing trivia out of forced flat portion of
 interpolated string

closes #1258
---
 .../cs/InterpolatedStringExpressions.test     |  4 ++++
 .../InterpolatedStringExpression.cs           |  7 ++++---
 Src/CSharpier/SyntaxPrinter/Token.cs          | 20 ++++++++++++++-----
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/Src/CSharpier.Tests/FormattingTests/TestFiles/cs/InterpolatedStringExpressions.test b/Src/CSharpier.Tests/FormattingTests/TestFiles/cs/InterpolatedStringExpressions.test
index e00c2d846..308bf5e41 100644
--- a/Src/CSharpier.Tests/FormattingTests/TestFiles/cs/InterpolatedStringExpressions.test
+++ b/Src/CSharpier.Tests/FormattingTests/TestFiles/cs/InterpolatedStringExpressions.test
@@ -8,6 +8,10 @@ public class ClassName
         // comment stays on this line
         $"two";
 
+    public string TrailingComment = someCondition
+        ? $"empty" // trailing comment
+        : someString;
+
     public string TwoValues = $"{SomeValue}{SomeOtherValue}";
 
     public string ForceFlatInString =
diff --git a/Src/CSharpier/SyntaxPrinter/SyntaxNodePrinters/InterpolatedStringExpression.cs b/Src/CSharpier/SyntaxPrinter/SyntaxNodePrinters/InterpolatedStringExpression.cs
index bce5981fb..bcfb74baa 100644
--- a/Src/CSharpier/SyntaxPrinter/SyntaxNodePrinters/InterpolatedStringExpression.cs
+++ b/Src/CSharpier/SyntaxPrinter/SyntaxNodePrinters/InterpolatedStringExpression.cs
@@ -31,12 +31,13 @@ public static Doc Print(InterpolatedStringExpressionSyntax node, FormattingConte
         };
 
         docs.AddRange(node.Contents.Select(o => Node.Print(o, context)));
-        docs.Add(Token.Print(node.StringEndToken, context));
+        docs.Add(Token.PrintWithoutTrailingTrivia(node.StringEndToken, context));
 
         return Doc.Concat(
-            // pull out the leading trivia so it doesn't get forced flat
+            // pull out the trivia so it doesn't get forced flat
             Token.PrintLeadingTrivia(node.StringStartToken, context),
-            Doc.ForceFlat(docs)
+            Doc.ForceFlat(docs),
+            Token.PrintTrailingTrivia(node.StringEndToken)
         );
     }
 
diff --git a/Src/CSharpier/SyntaxPrinter/Token.cs b/Src/CSharpier/SyntaxPrinter/Token.cs
index 3262ecd8f..7c3fe4c45 100644
--- a/Src/CSharpier/SyntaxPrinter/Token.cs
+++ b/Src/CSharpier/SyntaxPrinter/Token.cs
@@ -9,6 +9,11 @@ public static Doc PrintWithoutLeadingTrivia(SyntaxToken syntaxToken, FormattingC
         return PrintSyntaxToken(syntaxToken, context, skipLeadingTrivia: true);
     }
 
+    public static Doc PrintWithoutTrailingTrivia(SyntaxToken syntaxToken, FormattingContext context)
+    {
+        return PrintSyntaxToken(syntaxToken, context, skipTrailingTrivia: true);
+    }
+
     public static Doc Print(SyntaxToken syntaxToken, FormattingContext context)
     {
         return PrintSyntaxToken(syntaxToken, context);
@@ -30,7 +35,8 @@ private static Doc PrintSyntaxToken(
         SyntaxToken syntaxToken,
         FormattingContext context,
         Doc? suffixDoc = null,
-        bool skipLeadingTrivia = false
+        bool skipLeadingTrivia = false,
+        bool skipTrailingTrivia = false
     )
     {
         if (syntaxToken.RawSyntaxKind() == SyntaxKind.None)
@@ -113,10 +119,14 @@ or SyntaxKind.InterpolatedRawStringEndToken
         {
             docs.Add(syntaxToken.Text);
         }
-        var trailingTrivia = PrintTrailingTrivia(syntaxToken);
-        if (trailingTrivia != Doc.Null)
+
+        if (!skipTrailingTrivia)
         {
-            docs.Add(trailingTrivia);
+            var trailingTrivia = PrintTrailingTrivia(syntaxToken);
+            if (trailingTrivia != Doc.Null)
+            {
+                docs.Add(trailingTrivia);
+            }
         }
 
         if (suffixDoc != null)
@@ -344,7 +354,7 @@ private static bool IsMultiLineComment(SyntaxKind kind) =>
     private static bool IsRegion(SyntaxKind kind) =>
         kind is SyntaxKind.RegionDirectiveTrivia or SyntaxKind.EndRegionDirectiveTrivia;
 
-    private static Doc PrintTrailingTrivia(SyntaxToken node)
+    public static Doc PrintTrailingTrivia(SyntaxToken node)
     {
         return PrintTrailingTrivia(node.TrailingTrivia);
     }