add test for no fn attr on 'self' argument

crates/macro/ui-tests/invalid-self-fn-attrs.rs

@@ -0,0 +1,29 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub struct A {
+    inner: u32
+}
+
+#[wasm_bindgen]
+impl A {
+    #[wasm_bindgen]
+    pub fn method_with_self_attr1(
+        #[wasm_bindgen(unchecked_param_type = "number")]
+        &self,
+        arg: u32
+    ) -> JsValue {
+        (self.inner + arg).into()
+    }
+
+    #[wasm_bindgen]
+    pub fn method_with_self_attr2(
+        #[wasm_bindgen(param_description = "some description")]
+        &self,
+        arg: u32
+    ) -> JsValue {
+        (self.inner + arg).into()
+    }
+}
+
+fn main() {}

crates/macro/ui-tests/invalid-self-fn-attrs.stderr

@@ -0,0 +1,11 @@
+error: expected non-macro attribute, found attribute macro `wasm_bindgen`
+  --> ui-tests/invalid-self-fn-attrs.rs:12:11
+   |
+12 |         #[wasm_bindgen(unchecked_param_type = "number")]
+   |           ^^^^^^^^^^^^ not a non-macro attribute
+
+error: expected non-macro attribute, found attribute macro `wasm_bindgen`
+  --> ui-tests/invalid-self-fn-attrs.rs:21:11
+   |
+21 |         #[wasm_bindgen(param_description = "some description")]
+   |           ^^^^^^^^^^^^ not a non-macro attribute