Allow returns in default parameter values

Author: kddnewton

src/prism.c

@@ -15437,7 +15437,6 @@ parse_return(pm_parser_t *parser, pm_node_t *node) {
             case PM_CONTEXT_CASE_IN:
             case PM_CONTEXT_CASE_WHEN:
             case PM_CONTEXT_DEFAULT_PARAMS:
-            case PM_CONTEXT_DEF_PARAMS:
             case PM_CONTEXT_DEFINED:
             case PM_CONTEXT_ELSE:
             case PM_CONTEXT_ELSIF:
@@ -15483,6 +15482,7 @@ parse_return(pm_parser_t *parser, pm_node_t *node) {
             case PM_CONTEXT_BLOCK_RESCUE:
             case PM_CONTEXT_DEF_ELSE:
             case PM_CONTEXT_DEF_ENSURE:
+            case PM_CONTEXT_DEF_PARAMS:
             case PM_CONTEXT_DEF_RESCUE:
             case PM_CONTEXT_DEF:
             case PM_CONTEXT_LAMBDA_BRACES:

test/prism/fixtures/methods.txt

@@ -181,3 +181,8 @@ end
 def foo(bar = (def baz(bar) = bar; 1)) = 2
 
 def (class Foo; end).foo(bar = 1) = 2
+
+module Foo
+  def clone(opts = nil || (return self))
+  end
+end