Add parenthesis when type abbreviation is a tuple struct. Fixes #605 (#…

…609)
fsprojects · Dec 26, 2019 · 24a9fd1 · 24a9fd1
1 parent 4e471fe
commit 24a9fd1
Show file tree

Hide file tree

Showing 2 changed files with 43 additions and 3 deletions.
diff --git a/src/Fantomas.Tests/StructTests.fs b/src/Fantomas.Tests/StructTests.fs
@@ -86,3 +86,23 @@ let t = struct (1, 2)
 match t with
 | struct (x, y) -> ()
 """
+
+[<Test>]
+let ``struct tuple type abbreviation, 605`` () =
+    formatSourceString false "type TupleStruct = (struct (string * string))"  config
+    |> prepend newline
+    |> should equal """
+type TupleStruct = (struct (string * string))
+"""
+
+[<Test>]
+let ``struct tuple type abbreviation, sigfile`` () =
+    formatSourceString true """namespace meh
+
+type TupleStruct = (struct (string * string))"""  config
+    |> prepend newline
+    |> should equal """
+namespace meh
+
+type TupleStruct = (struct (string * string))
+"""
diff --git a/src/Fantomas/CodePrinter.fs b/src/Fantomas/CodePrinter.fs
@@ -1570,7 +1570,16 @@ and genTypeDefn astContext (TypeDef(ats, px, ao, tds, tcs, tdr, ms, s, preferPos
     | Simple TDSRNone -> 
         typeName
     | Simple(TDSRTypeAbbrev t) ->
-        let genTypeAbbrev = genType astContext false t
+        let genTypeAbbrev =
+            let needsParenthesis =
+                match t with
+                | SynType.Tuple(isStruct, typeNames, _) ->
+                    (isStruct && List.length typeNames > 1)
+                | _ -> false
+
+            ifElse needsParenthesis sepOpenT sepNone +>
+            genType astContext false t +>
+            ifElse needsParenthesis sepCloseT sepNone
 
         let genMembers =
             ifElse (List.isEmpty ms)
@@ -1703,8 +1712,19 @@ and genSigTypeDefn astContext (SigTypeDef(ats, px, ao, tds, tcs, tdr, ms, s, pre
 
     | SigSimple TDSRNone -> 
         typeName
-    | SigSimple(TDSRTypeAbbrev t) -> 
-        typeName +> sepEq +> sepSpace +> genType astContext false t
+    | SigSimple(TDSRTypeAbbrev t) ->
+        let genTypeAbbrev =
+            let needsParenthesis =
+                match t with
+                | SynType.Tuple(isStruct, typeNames, _) ->
+                    (isStruct && List.length typeNames > 1)
+                | _ -> false
+
+            ifElse needsParenthesis sepOpenT sepNone +>
+            genType astContext false t +>
+            ifElse needsParenthesis sepCloseT sepNone
+
+        typeName +> sepEq +> sepSpace +> genTypeAbbrev
     | SigSimple(TDSRException(ExceptionDefRepr(ats, px, ao, uc))) ->
             genExceptionBody astContext ats px ao uc