From fd0bf09bc4cd14cff68e0e4c876d40095f2acae6 Mon Sep 17 00:00:00 2001
From: Julien Couvreur <jcouv@users.noreply.github.com>
Date: Tue, 24 Mar 2020 09:03:54 -0700
Subject: [PATCH] Formatting: force a space after attribute on parameter
 (#42466)

---
 .../CSharpTest/Formatting/FormattingTests.cs  | 42 ++++++++++++++++++-
 .../Rules/TokenBasedFormattingRule.cs         | 18 ++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/src/Workspaces/CSharpTest/Formatting/FormattingTests.cs b/src/Workspaces/CSharpTest/Formatting/FormattingTests.cs
index 627ef65090e..7ba8f685dd7 100644
--- a/src/Workspaces/CSharpTest/Formatting/FormattingTests.cs
+++ b/src/Workspaces/CSharpTest/Formatting/FormattingTests.cs
@@ -4435,7 +4435,7 @@ void AddClass(string name,[OptionalAttribute]    object position,[OptionalAttrib
 
             var expected = @"class Program
 {
-    void AddClass(string name, [OptionalAttribute]    object position, [OptionalAttribute]    object bases)
+    void AddClass(string name, [OptionalAttribute] object position, [OptionalAttribute] object bases)
     {
     }
 }";
@@ -9555,5 +9555,45 @@ class C
     };
 }".Replace("&nbsp;", "\u00A0"));
         }
+
+        [Fact, WorkItem(41022, "https://github.com/dotnet/roslyn/issues/41022")]
+        [Trait(Traits.Feature, Traits.Features.Formatting)]
+        public async Task SpacingAfterAttribute()
+        {
+            var code = @"class C
+{
+    void M([My]string?[]?[] x)
+    {
+    }
+}";
+            var expectedCode = @"class C
+{
+    void M([My] string?[]?[] x)
+    {
+    }
+}";
+
+            await AssertFormatAsync(expectedCode, code);
+        }
+
+        [Fact, WorkItem(41022, "https://github.com/dotnet/roslyn/issues/41022")]
+        [Trait(Traits.Feature, Traits.Features.Formatting)]
+        public async Task SpacingAfterAttribute_Multiple()
+        {
+            var code = @"class C
+{
+    void M([My][My]  int x)
+    {
+    }
+}";
+            var expectedCode = @"class C
+{
+    void M([My][My] int x)
+    {
+    }
+}";
+
+            await AssertFormatAsync(expectedCode, code);
+        }
     }
 }
diff --git a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Formatting/Rules/TokenBasedFormattingRule.cs b/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Formatting/Rules/TokenBasedFormattingRule.cs
index f0deeab33cf..f7b7ce6a2b8 100644
--- a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Formatting/Rules/TokenBasedFormattingRule.cs
+++ b/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/CSharp/Formatting/Rules/TokenBasedFormattingRule.cs
@@ -258,6 +258,24 @@ public override AdjustSpacesOperation GetAdjustSpacesOperation(SyntaxToken previ
                 return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpacesIfOnSingleLine);
             }
 
+            if (previousToken.IsKind(SyntaxKind.CloseBracketToken) &&
+                previousToken.Parent.IsKind(SyntaxKind.AttributeList) &&
+                previousToken.Parent.IsParentKind(SyntaxKind.Parameter))
+            {
+                if (currentToken.IsKind(SyntaxKind.OpenBracketToken))
+                {
+                    // multiple attribute on parameter stick together
+                    // void M([...][...]
+                    return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpacesIfOnSingleLine);
+                }
+                else
+                {
+                    // attribute is spaced from parameter type
+                    // void M([...] int
+                    return CreateAdjustSpacesOperation(1, AdjustSpacesOption.ForceSpacesIfOnSingleLine);
+                }
+            }
+
             // extension method on tuple type
             // M(this (
             if (currentToken.Kind() == SyntaxKind.OpenParenToken &&
-- 
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