[CS2] return and export default can now accept implicit objects (#4532)

* Start with the test I want to pass: return an implicit (braces-less) object

* Update Rewriter class to follow pattern of nodes.coffee; move debugging snippet to where it’ll work in CS2

* Allow export default implicit object

* `return` assumes a continuation onto the next line *if* the next line is indented

* Fix comment; improve test

lib/coffeescript/lexer.js

@@ -465,7 +465,7 @@
         return indent.length;
       }
       if (size > this.indent) {
-        if (noNewlines) {
+        if (noNewlines || this.tag() === 'RETURN') {
           this.indebt = size - this.indent;
           this.suppressNewlines();
           return indent.length;
@@ -890,7 +890,7 @@
 
     unfinished() {
       var ref;
-      return LINE_CONTINUER.test(this.chunk) || ((ref = this.tag()) === '\\' || ref === '.' || ref === '?.' || ref === '?::' || ref === 'UNARY' || ref === 'MATH' || ref === 'UNARY_MATH' || ref === '+' || ref === '-' || ref === '**' || ref === 'SHIFT' || ref === 'RELATION' || ref === 'COMPARE' || ref === '&' || ref === '^' || ref === '|' || ref === '&&' || ref === '||' || ref === 'BIN?' || ref === 'THROW' || ref === 'EXTENDS');
+      return LINE_CONTINUER.test(this.chunk) || ((ref = this.tag()) === '\\' || ref === '.' || ref === '?.' || ref === '?::' || ref === 'UNARY' || ref === 'MATH' || ref === 'UNARY_MATH' || ref === '+' || ref === '-' || ref === '**' || ref === 'SHIFT' || ref === 'RELATION' || ref === 'COMPARE' || ref === '&' || ref === '^' || ref === '|' || ref === '&&' || ref === '||' || ref === 'BIN?' || ref === 'THROW' || ref === 'EXTENDS' || ref === 'DEFAULT');
     }
 
     formatString(str, options) {

lib/coffeescript/rewriter.js

@@ -1,6 +1,6 @@
 // Generated by CoffeeScript 2.0.0-beta1
 (function() {
-  var BALANCED_PAIRS, CALL_CLOSERS, EXPRESSION_CLOSE, EXPRESSION_END, EXPRESSION_START, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, IMPLICIT_UNSPACED_CALL, INVERSES, LINEBREAKS, SINGLE_CLOSERS, SINGLE_LINERS, generate, k, left, len, rite,
+  var BALANCED_PAIRS, CALL_CLOSERS, EXPRESSION_CLOSE, EXPRESSION_END, EXPRESSION_START, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, IMPLICIT_UNSPACED_CALL, INVERSES, LINEBREAKS, Rewriter, SINGLE_CLOSERS, SINGLE_LINERS, generate, k, left, len, rite,
     indexOf = [].indexOf;
 
   generate = function(tag, value, origin) {
@@ -13,7 +13,7 @@
     return tok;
   };
 
-  exports.Rewriter = (function() {
+  exports.Rewriter = Rewriter = (function() {
     class Rewriter {
       rewrite(tokens1) {
         this.tokens = tokens1;

src/grammar.coffee

@@ -229,7 +229,6 @@ grammar =
     o 'AWAIT RETURN',                           -> new AwaitReturn
   ]
 
-
   # A block comment.
   Comment: [
     o 'HERECOMMENT',                            -> new Comment $1

src/lexer.coffee

@@ -403,7 +403,7 @@ exports.Lexer = class Lexer
       return indent.length
 
     if size > @indent
-      if noNewlines
+      if noNewlines or @tag() is 'RETURN'
         @indebt = size - @indent
         @suppressNewlines()
         return indent.length
@@ -455,7 +455,7 @@ exports.Lexer = class Lexer
     this
 
   # Matches and consumes non-meaningful whitespace. Tag the previous token
-  # as being "spaced", because there are some cases where it makes a difference.
+  # as being “spaced”, because there are some cases where it makes a difference.
   whitespaceToken: ->
     return 0 unless (match = WHITESPACE.exec @chunk) or
                     (nline = @chunk.charAt(0) is '\n')
@@ -790,7 +790,7 @@ exports.Lexer = class Lexer
     LINE_CONTINUER.test(@chunk) or
     @tag() in ['\\', '.', '?.', '?::', 'UNARY', 'MATH', 'UNARY_MATH', '+', '-',
                '**', 'SHIFT', 'RELATION', 'COMPARE', '&', '^', '|', '&&', '||',
-               'BIN?', 'THROW', 'EXTENDS']
+               'BIN?', 'THROW', 'EXTENDS', 'DEFAULT']
 
   formatString: (str, options) ->
     @replaceUnicodeCodePointEscapes str.replace(STRING_OMIT, '$1'), options

src/rewriter.coffee

@@ -14,11 +14,7 @@ generate = (tag, value, origin) ->
 
 # The **Rewriter** class is used by the [Lexer](lexer.html), directly against
 # its internal array of tokens.
-class exports.Rewriter
-
-  # Helpful snippet for debugging:
-  #
-  #     console.log (t[0] + '/' + t[1] for t in @tokens).join ' '
+exports.Rewriter = class Rewriter
 
   # Rewrite the token stream in multiple passes, one logical filter at
   # a time. This could certainly be changed into a single pass through the
@@ -26,6 +22,8 @@ class exports.Rewriter
   # like this. The order of these passes matters -- indentation must be
   # corrected before implicit parentheses can be wrapped around blocks of code.
   rewrite: (@tokens) ->
+    # Helpful snippet for debugging:
+    #     console.log (t[0] + '/' + t[1] for t in @tokens).join ' '
     @removeLeadingNewlines()
     @closeOpenCalls()
     @closeOpenIndexes()
@@ -186,7 +184,7 @@ class exports.Rewriter
       # Don't end an implicit call on next indent if any of these are in an argument
       if inImplicitCall() and tag in ['IF', 'TRY', 'FINALLY', 'CATCH',
         'CLASS', 'SWITCH']
-        stack.push ['CONTROL', i, ours: true]
+        stack.push ['CONTROL', i, ours: yes]
         return forward(1)
 
       if tag is 'INDENT' and inImplicit()

test/modules.coffee

@@ -353,6 +353,28 @@ test "export default object", ->
     };"""
   eq toJS(input), output
 
+test "export default implicit object", ->
+  input = "export default foo: 'bar', baz: 'qux'"
+  output = """
+    export default {
+      foo: 'bar',
+      baz: 'qux'
+    };"""
+  eq toJS(input), output
+
+test "export default multiline implicit object", ->
+  input = """
+    export default
+      foo: 'bar',
+      baz: 'qux'
+    """
+  output = """
+    export default {
+      foo: 'bar',
+      baz: 'qux'
+    };"""
+  eq toJS(input), output
+
 test "export default assignment expression", ->
   input = "export default foo = 'bar'"
   output = """

test/objects.coffee

@@ -575,3 +575,15 @@ test "#4324: Shorthand after interpolated key", ->
   obj = {"#{1}": 1, a}
   eq 1, obj[1]
   eq 2, obj.a
+
+test "#1263: Braceless object return", ->
+  fn = ->
+    return
+      a: 1
+      b: 2
+      c: -> 3
+
+  obj = fn()
+  eq 1, obj.a
+  eq 2, obj.b
+  eq 3, obj.c()