Add and keyword between multiple member constraints. Fixes fsprojects…

…#886

src/Fantomas.Tests/SignatureTests.fs

@@ -581,4 +581,21 @@ namespace Bar
 type A =
     internal { ALongIdentifier: string
                YetAnotherLongIdentifier: bool }
+"""
+
+[<Test>]
+let ``multiple constraints on function declaration, 886`` () =
+    formatSourceString true """namespace Blah
+
+module Foo =
+    val inline sum : ('a -> ^value) -> 'a Foo -> ^value
+        when ^value : (static member (+) : ^value * ^value -> ^value) and ^value : (static member Zero : ^value)
+"""  config
+    |> prepend newline
+    |> should equal """
+namespace Blah
+
+module Foo =
+    val inline sum: ('a -> ^value) -> 'a Foo -> ^value
+        when ^value: (static member (+): ^value * ^value -> ^value) and ^value: (static member Zero: ^value)
 """

src/Fantomas/CodePrinter.fs

@@ -2262,8 +2262,9 @@ and genConstraints astContext (t: SynType) =
     match t with
     | TWithGlobalConstraints(t, tcs) ->
         genTypeByLookup astContext t
-        +> onlyIf (List.isNotEmpty tcs) (!- " when ")
-        +> col sepSpace tcs (genTypeConstraint astContext)
+        +> sepSpaceOrNlnIfExpressionExceedsPageWidth
+            (ifElse (List.isNotEmpty tcs) (!- "when ") sepSpace
+            +> col wordAnd tcs (genTypeConstraint astContext))
     | _ -> sepNone
 
 and genTyparDecl astContext (TyparDecl(ats, tp)) =

src/Fantomas/Context.fs

@@ -620,6 +620,12 @@ let internal sepSpaceOrIndentAndNlnIfExpressionExceedsPageWidth expr (ctx:Contex
         (indent +> sepNln) unindent // before and after for long expressions
         expr ctx
 
+let internal sepSpaceOrNlnIfExpressionExceedsPageWidth expr (ctx:Context) =
+    expressionExceedsPageWidth
+        sepSpace sepNone // before and after for short expressions
+        sepNln unindent // before and after for long expressions
+        expr ctx
+
 let internal autoNlnIfExpressionExceedsPageWidth expr (ctx: Context) =
     expressionExceedsPageWidth
         sepNone sepNone // before and after for short expressions