Refine sameLine implicit object tagging [Fixes #4568] (#4598)

Author: Julian Rosse

lib/coffeescript/rewriter.js

@@ -336,8 +336,9 @@ exports.Rewriter = class Rewriter
 
       # Mark all enclosing objects as not sameLine
       if tag in LINEBREAKS
-        for stackItem in stack by -1 when isImplicitObject stackItem
-          stackItem[2].sameLine = no
+        for stackItem in stack by -1
+          break unless isImplicit stackItem
+          stackItem[2].sameLine = no if isImplicitObject stackItem
 
       newLine = prevTag is 'OUTDENT' or prevToken.newLine
       if tag in IMPLICIT_END or tag in CALL_CLOSERS and newLine

src/rewriter.coffee

@@ -232,6 +232,16 @@ test "method call chaining inside objects", ->
       .c
   eq 42, result.b
 
+test "#4568: refine sameLine implicit object tagging", ->
+  condition = yes
+  fn = -> yes
+
+  x =
+    fn bar: {
+      foo: 123
+    } if not condition
+  eq x, undefined
+
 # Nested blocks caused by paren unwrapping
 test "#1492: Nested blocks don't cause double semicolons", ->
   js = CoffeeScript.compile '(0;0)'