Add a test for #2003

Author: topecongiro

tests/source/fn-simple.rs

@@ -52,3 +52,10 @@ pub fn waltz(cwd: &Path) -> CliAssert {
         }
     }
 }
+
+// #2003
+mod foo {
+    fn __bindgen_test_layout_i_open0_c_open1_char_a_open2_char_close2_close1_close0_instantiation() {
+        foo();
+    }
+}

tests/target/fn-simple.rs

@@ -93,3 +93,11 @@ pub fn waltz(cwd: &Path) -> CliAssert {
         }
     }
 }
+
+// #2003
+mod foo {
+    fn __bindgen_test_layout_i_open0_c_open1_char_a_open2_char_close2_close1_close0_instantiation()
+    {
+        foo();
+    }
+}