Don't add newline to namespace where the first trivia is a newline

src/Fantomas.Tests/ClassTests.fs

@@ -540,17 +540,4 @@ let ``unit parameter to inherited class`` () =
     |> should equal """
 type Child() =
     inherit Parent()
-"""
-
-[<Test>]
-let ``class let binding with attribute should not add newline, 786`` () =
-    formatSourceString false """type A() =
-
-    [<Bar>]
-    let foo = ()
-"""  config
-    |> should equal """type A() =
-
-    [<Bar>]
-    let foo = ()
-"""
+"""

src/Fantomas.Tests/ModuleTests.fs

@@ -439,10 +439,25 @@ type UrlModel =
       Defines: string }
 """
 
-[<TestCase(true)>]
-[<TestCase(false)>]
-let ``comment is first trivia in module should not add newline, 784`` (isFsiFile) =
-    formatSourceString isFsiFile """
+[<Test>]
+let ``comment is first trivia in module should not add newline, 784`` () =
+    formatSourceString false """
+module foo
+
+// bar
+// baz
+"""  config
+    |> prepend newline
+    |> should equal """
+module foo
+
+// bar
+// baz
+"""
+
+[<Test>]
+let ``comment is first trivia in module in script file should not add newline, 784`` () =
+    formatSourceString true """
 module foo
 
 // bar
@@ -455,3 +470,35 @@ module foo
 // bar
 // baz
 """
+
+[<Test>]
+let ``comment is first trivia in namespace should not add newline, 784`` () =
+    formatSourceString false """
+namespace foo.quz
+
+// bar
+// baz
+"""  config
+    |> prepend newline
+    |> should equal """
+namespace foo.quz
+
+// bar
+// baz
+"""
+
+[<Test>]
+let ``comment is first trivia in namespace in signature file should not add newline, 784`` () =
+    formatSourceString true """
+namespace foo.quz
+
+// bar
+// baz
+"""  config
+    |> prepend newline
+    |> should equal """
+namespace foo.quz
+
+// bar
+// baz
+"""

src/Fantomas/CodePrinter.fs

@@ -125,7 +125,10 @@ and genModuleOrNamespace astContext (ModuleOrNamespace(ats, px, ao, s, mds, isRe
         let firstDecl = List.tryHead mds
         match firstDecl with
         | None ->
-            sepNlnForEmptyModule node.Range +> sepNln
+            if moduleKind.IsModule then
+                sepNlnForEmptyModule node.Range +> sepNln
+            else
+                sepNlnForEmptyNamespace node.Range +> sepNln
         | Some mdl ->
             let attrRanges = getRangesFromAttributesFromModuleDeclaration mdl
             sepNlnConsideringTriviaContentBeforeWithAttributes mdl.Range attrRanges +> sepNln
@@ -166,7 +169,10 @@ and genSigModuleOrNamespace astContext (SigModuleOrNamespace(ats, px, ao, s, mds
         let firstDecl = List.tryHead mds
         match firstDecl with
         | None ->
-            sepNlnForEmptyModule range +> rep 2 sepNln
+            if moduleKind.IsModule then
+                sepNlnForEmptyModule range +> rep 2 sepNln
+            else
+                sepNlnForEmptyNamespace range +> sepNln
         | Some mdl ->
             sepNlnConsideringTriviaContentBefore mdl.Range +> sepNln
 

src/Fantomas/Context.fs

@@ -749,6 +749,12 @@ let private findTriviaMainNodeOrTokenOnEndFromRange nodes (range:range) =
     |> List.tryFind(fun n ->
         Trivia.isMainNode n && RangeHelpers.rangeEq n.Range range
         || Trivia.isToken n && RangeHelpers.rangeEndEq n.Range range)
+
+let private findTriviaMainNodeOrTokenContainedInRange nodes (range:range) =
+    nodes
+    |> List.tryFind(fun n ->
+        Trivia.isMainNode n && RangeHelpers.``range contains`` range n.Range 
+        || Trivia.isToken n && RangeHelpers.``range contains`` range n.Range)
 
 let private findTriviaTokenFromRange nodes (range:range) =
     nodes
@@ -891,6 +897,14 @@ let internal sepNlnForEmptyModule (moduleRange:range) ctx =
     | _ ->
         sepNln ctx
 
+let internal sepNlnForEmptyNamespace (namespaceRange:range) ctx =
+    let emptyNamespaceRange = mkRange namespaceRange.FileName (mkPos 0 0) namespaceRange.End
+    match findTriviaMainNodeOrTokenContainedInRange ctx.Trivia emptyNamespaceRange with
+    | Some node when hasPrintableContent node.ContentBefore || hasPrintableContent node.ContentAfter ->
+        ctx
+    | _ ->
+        sepNln ctx
+
 let internal sepNlnTypeAndMembers (firstMemberRange: range option) ctx =
     match firstMemberRange with
     | Some range when (ctx.Config.NewlineBetweenTypeDefinitionAndMembers) ->