Fix compilation and docs

The compilation part is effectively a cherry pick from master

DESIGN.md

@@ -538,22 +538,14 @@ code for this we'll see:
 ```js
 import * as wasm from './js_hello_world_bg';
 
+export class Foo {
+    static __construct(ptr) {
+        return new Foo(ptr);
+    }
 
-class ConstructorToken {
     constructor(ptr) {
         this.ptr = ptr;
     }
-}
-
-export class Foo {
-
-    constructor(...args) {
-        if (args.length === 1 && args[0] instanceof ConstructorToken) {
-            this.ptr = args[0].ptr;
-            return;
-        }
-        throw new Error('you cannot invoke `new` directly without having a method annotated a constructor');
-    }
 
     free() {
         const ptr = this.ptr;
@@ -563,7 +555,7 @@ export class Foo {
 
     static new(arg0) {
         const ret = wasm.foo_new(arg0);
-        return new Foo(new ConstructorToken(ret));
+        return Foo.__construct(ret)
     }
 
     get() {

crates/cli-support/src/lib.rs

@@ -110,7 +110,7 @@ impl Bindgen {
         // execute a shim function which informs us about its type so we can
         // then generate the appropriate bindings.
         let instance = wasmi::Module::from_parity_wasm_module(module.clone())?;
-        let instance = wasmi::ModuleInstance::new(&imodule, &MyResolver)?;
+        let instance = wasmi::ModuleInstance::new(&instance, &MyResolver)?;
         let instance = instance.not_started_instance();
 
         let (js, ts) = {
@@ -128,7 +128,7 @@ impl Bindgen {
                 function_table_needed: false,
                 run_descriptor: &|name| {
                     let mut v = MyExternals(Vec::new());
-                    let ret = imodulei
+                    let ret = instance
                         .invoke_export(name, &[], &mut v)
                         .expect("failed to run export");
                     assert!(ret.is_none());