Improve printing of modules types with one line inside (#2709)

* improve printing of modules with one line

* add history entry

HISTORY.md

@@ -1,5 +1,6 @@
 ## 3.9 (unreleased)
 
+- Print module type body on separate line (@SanderSpies) [#2709](https://github.com/reasonml/reason/pull/2709)
 - Fix missing patterns around contraint pattern (a pattern with a type annotation).
 - Fix top level extension printing
 - Remove the dependency on the `result` package, which isn't needed for OCaml

src/reason-parser/reason_pprint_ast.ml

@@ -7419,7 +7419,7 @@ let printer = object(self:'self)
           ~comments:self#comments
           s
         in
-        let shouldBreakLabel = if List.length s > 1 then `Always else `Auto in
+        let shouldBreakLabel = if List.length s > 0 then `Always else `Auto in
         label
           ~indent:0
           ~break:shouldBreakLabel

test/modules.t/run.t

@@ -113,7 +113,9 @@ Format modules
     tmp + 30;
   };
 
-  module type HasTT = {type tt;};
+  module type HasTT = {
+    type tt;
+  };
 
   module SubModule: HasTT = {
     type tt = int;
@@ -123,7 +125,9 @@ Format modules
     module SubModuleThatHasTT = SubModule;
   };
 
-  module type HasPolyType = {type t('a);};
+  module type HasPolyType = {
+    type t('a);
+  };
   
   module type HasDestructivelySubstitutedPolyType =
     HasPolyType with type t('a) := list('a);
@@ -200,10 +204,16 @@ Format modules
       type tt = string;
     });
   
-  module type SigResult = {let result: int;};
+  module type SigResult = {
+    let result: int;
+  };
   
-  module type ASig = {let a: int;};
-  module type BSig = {let b: int;};
+  module type ASig = {
+    let a: int;
+  };
+  module type BSig = {
+    let b: int;
+  };
   module AMod = {
     let a = 10;
   };
@@ -422,7 +432,9 @@ Format modules
   };
 
   /* From http://stackoverflow.com/questions/1986374/higher-order-type-constructors-and-functors-in-ocaml */
-  module type Type = {type t;};
+  module type Type = {
+    type t;
+  };
   module Char = {
     type t = char;
   };
@@ -483,7 +495,9 @@ Format modules
     let myValue = {recordField: "hello"};
   });
 
-  module type HasInt = {let x: int;};
+  module type HasInt = {
+    let x: int;
+  };
 
   module MyModule = {
     let x = 10;

test/modules_no_semi.t/run.t

@@ -113,7 +113,9 @@ Format modules no semi
     tmp + 30;
   };
 
-  module type HasTT = {type tt;};
+  module type HasTT = {
+    type tt;
+  };
 
   module SubModule: HasTT = {
     type tt = int;
@@ -123,7 +125,9 @@ Format modules no semi
     module SubModuleThatHasTT = SubModule;
   };
 
-  module type HasPolyType = {type t('a);};
+  module type HasPolyType = {
+    type t('a);
+  };
   
   module type HasDestructivelySubstitutedPolyType =
     HasPolyType with type t('a) := list('a);
@@ -200,10 +204,16 @@ Format modules no semi
       type tt = string;
     });
   
-  module type SigResult = {let result: int;};
+  module type SigResult = {
+    let result: int;
+  };
   
-  module type ASig = {let a: int;};
-  module type BSig = {let b: int;};
+  module type ASig = {
+    let a: int;
+  };
+  module type BSig = {
+    let b: int;
+  };
   module AMod = {
     let a = 10;
   };
@@ -422,7 +432,9 @@ Format modules no semi
   };
 
   /* From http://stackoverflow.com/questions/1986374/higher-order-type-constructors-and-functors-in-ocaml */
-  module type Type = {type t;};
+  module type Type = {
+    type t;
+  };
   module Char = {
     type t = char;
   };
@@ -483,7 +495,9 @@ Format modules no semi
     let myValue = {recordField: "hello"};
   });
 
-  module type HasInt = {let x: int;};
+  module type HasInt = {
+    let x: int;
+  };
 
   module MyModule = {
     let x = 10;

test/whitespace-rei.t/run.t

@@ -142,16 +142,22 @@ Format whitespace in .rei files
   include Shared;
 
   /** doc attached */
-  module type X = {let x: int;};
+  module type X = {
+    let x: int;
+  };
 
   /** doc attached with whitespace */
 
-  module type X = {let x: int;};
+  module type X = {
+    let x: int;
+  };
 
   /** doc attached with whitespace and comment */
 
   /* test */
-  module type X = {let x: int;};
+  module type X = {
+    let x: int;
+  };
 
   /** doc attached */
   module X: MX;

test/wrapping-re.t/run.t

@@ -2568,8 +2568,12 @@ Format wrapping in .re files
       1 + 2 + 3 + 3,
     );
 
-  module type ASig = {let a: int;};
-  module type BSig = {let b: int;};
+  module type ASig = {
+    let a: int;
+  };
+  module type BSig = {
+    let b: int;
+  };
   module AMod = {
     let a = 10;
   };