fix jashkenas#5013

Author: zdenko

lib/coffeescript/nodes.js

@@ -863,11 +863,14 @@ exports.Value = class Value extends Base
   constructor: (base, props, tag, isDefaultValue = no) ->
     super()
     return base if not props and base instanceof Value
-    # When `Parens` block includes a `StatementLiteral` (e.g. `(b; break) for a in arr`),
+    # When `Parens` block includes a `StatementLiteral`, `Return`, `YieldReturn` or `AwaitReturn`
+    # (e.g. `(b; break) for a in arr`, '-> (return)`, '-> (yield return)`),
     # it won't compile since `Parens` (`(b; break)`) is compiled as `Value` and
     # pure statement (`break`) can't be used in an expression.
     # For this reasons, we return `Block` instead of `Parens`.
-    return base.unwrap() if base instanceof Parens and base.contains (n) -> n instanceof StatementLiteral
+    if base instanceof Parens and
+        base.contains (n) -> n instanceof StatementLiteral or n instanceof Return
+      return base.unwrap()
     @base           = base
     @properties     = props or []
     @[tag]          = yes if tag

src/nodes.coffee

@@ -953,15 +953,6 @@ test "`yield` outside of a function", ->
     ^^^^^^^^^^^^
   '''
 
-test "#4097: `yield return` as an expression", ->
-  assertErrorFormat '''
-    -> (yield return)
-  ''', '''
-    [stdin]:1:5: error: cannot use a pure statement in an expression
-    -> (yield return)
-        ^^^^^^^^^^^^
-  '''
-
 test "`&&=` and `||=` with a space in-between", ->
   assertErrorFormat '''
     a = 0

test/error_messages.coffee

@@ -572,3 +572,17 @@ test "#4657: destructured array parameters", ->
   result = f [1, 2, 3, 4]
   arrayEq result.a, [1, 2, 3]
   eq result.b, 4
+
+test "#5013: return statements in parentheses", ->
+  compile = (code) -> CoffeeScript.compile(code, bare: yes).trim().replace(/\s+/g, " ")
+
+  eq "(function() {});",         compile("-> (return)")
+  eq "(function*() {});",        compile("-> (yield return)")
+  eq "(async function() {});",   compile("-> (await return)")
+
+  foo = (cond) ->
+    (a = 1; return) if cond
+    a = 2
+
+  eq undefined, foo yes
+  eq 2, foo no