diff --git a/IPython/core/magics/execution.py b/IPython/core/magics/execution.py
index 877e7cb..3734b0c 100644
--- a/IPython/core/magics/execution.py
+++ b/IPython/core/magics/execution.py
@@ -1013,6 +1013,13 @@ python-profiler package from non-free.""")
         ast_setup = self.shell.transform_ast(ast_setup)
         ast_stmt = self.shell.transform_ast(ast_stmt)
 
+        # Check that these compile to valid Python code *outside* the timer func
+        # Invalid code may become valid when put inside the function & loop,
+        # which messes up error messages.
+        # https://github.com/ipython/ipython/issues/10636
+        self.shell.compile(ast_setup, "<magic-timeit-setup>", "exec")
+        self.shell.compile(ast_stmt, "<magic-timeit-stmt>", "exec")
+
         # This codestring is taken from timeit.template - we fill it in as an
         # AST, so that we can apply our AST transformations to the user code
         # without affecting the timing code.
diff --git a/IPython/core/tests/test_magic.py b/IPython/core/tests/test_magic.py
index eb40331..fde9e71 100644
--- a/IPython/core/tests/test_magic.py
+++ b/IPython/core/tests/test_magic.py
@@ -583,6 +583,9 @@ def test_timeit_futures():
     ip.compile.reset_compiler_flags()
     with tt.AssertNotPrints('0.25'):
         ip.run_line_magic('timeit', '-n1 -r1 print(1/4)')
+def test_timeit_invalid_return():
+    with nt.assert_raises_regexp(SyntaxError, "outside function"):
+        _ip.run_line_magic('timeit', 'return')
 
 @dec.skipif(execution.profile is None)
 def test_prun_special_syntax():