Fix AST generation of a naked return

NEWS.rst

@@ -1,5 +1,12 @@
 .. default-role:: code
 
+Unreleased
+==============================
+
+Bug Fixes
+------------------------------
+* Fix `(return)` so it works correctly to exit a Python 2 generator
+
 0.14.0
 ==============================
 

hy/compiler.py

@@ -2040,7 +2040,9 @@ class HyASTCompiler(object):
     @checkargs(max=1)
     def compile_return(self, expr):
         ret = Result()
-        if len(expr) > 1:
+        if len(expr) == 1:
+            return asty.Return(expr, value=None)
+
         ret += self.compile(expr[1])
         return ret + asty.Return(expr, value=ret.force_expr)
 

tests/compilers/test_ast.py

@@ -8,7 +8,7 @@ from __future__ import unicode_literals
 from hy import HyString
 from hy.models import HyObject
 from hy.compiler import hy_compile
-from hy.importer import import_buffer_to_hst
+from hy.importer import hy_eval, import_buffer_to_hst
 from hy.errors import HyCompileError, HyTypeError
 from hy.lex.exceptions import LexException
 from hy._compat import PY3
@@ -30,6 +30,10 @@ def can_compile(expr):
     return hy_compile(import_buffer_to_hst(expr), "__main__")
 
 
+def can_eval(expr):
+    return hy_eval(import_buffer_to_hst(expr))
+
+
 def cant_compile(expr):
     try:
         hy_compile(import_buffer_to_hst(expr), "__main__")
@@ -664,3 +668,8 @@ def test_ast_good_yield_from():
 def test_ast_bad_yield_from():
     "Make sure AST can't compile invalid yield-from"
     cant_compile("(yield-from)")
+
+
+def test_eval_generator_with_return():
+    """Ensure generators with a return statement works."""
+    can_eval("(fn [] (yield 1) (yield 2) (return))")