Vendor dependencies

Let's see how I like this workflow.

vendor/wasm-bindgen/tests/wasm/duplicates.rs

@@ -0,0 +1,57 @@
+use wasm_bindgen_test::*;
+
+pub mod same_function_different_locations_a {
+    use wasm_bindgen::prelude::*;
+
+    #[wasm_bindgen(module = "tests/wasm/duplicates_a.js")]
+    extern "C" {
+        pub fn foo();
+        pub static bar: JsValue;
+    }
+}
+
+pub mod same_function_different_locations_b {
+    use wasm_bindgen::prelude::*;
+
+    #[wasm_bindgen(module = "tests/wasm/duplicates_a.js")]
+    extern "C" {
+        pub fn foo();
+        pub static bar: JsValue;
+    }
+}
+
+#[wasm_bindgen_test]
+fn same_function_different_locations() {
+    same_function_different_locations_a::foo();
+    same_function_different_locations_b::foo();
+    assert_eq!(*same_function_different_locations_a::bar, 3);
+    assert_eq!(*same_function_different_locations_a::bar, 3);
+}
+
+pub mod same_function_different_modules_a {
+    use wasm_bindgen::prelude::*;
+
+    #[wasm_bindgen(module = "tests/wasm/duplicates_b.js")]
+    extern "C" {
+        pub fn foo() -> bool;
+        pub static bar: JsValue;
+    }
+}
+
+pub mod same_function_different_modules_b {
+    use wasm_bindgen::prelude::*;
+
+    #[wasm_bindgen(module = "tests/wasm/duplicates_c.js")]
+    extern "C" {
+        pub fn foo() -> bool;
+        pub static bar: JsValue;
+    }
+}
+
+#[wasm_bindgen_test]
+fn same_function_different_modules() {
+    assert!(same_function_different_modules_a::foo());
+    assert!(!same_function_different_modules_b::foo());
+    assert_eq!(*same_function_different_modules_a::bar, 4);
+    assert_eq!(*same_function_different_modules_b::bar, 5);
+}