Remove support for the version attribute

First added in #161 this never ended up panning out, so let's remove the
experimental suport which isn't actually used by anything today and hold off on
any other changes until an RFC happens.

crates/backend/src/ast.rs

@@ -56,7 +56,6 @@ pub enum MethodSelf {
 #[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 pub struct Import {
     pub module: Option<String>,
-    pub version: Option<String>,
     pub js_namespace: Option<Ident>,
     pub kind: ImportKind,
 }
@@ -301,33 +300,8 @@ impl Variant {
 
 impl Import {
     fn shared(&self) -> Result<shared::Import, Diagnostic> {
-        match (&self.module, &self.version) {
-            (&Some(ref m), None) if m.starts_with("./") => {}
-            (&Some(ref m), &Some(_)) if m.starts_with("./") => {
-                panic!(
-                    "when a module path starts with `./` that indicates \
-                     that a local file is being imported so the `version` \
-                     key cannot also be specified"
-                );
-            }
-            (&Some(_), &Some(_)) => {}
-            (&Some(_), &None) => panic!(
-                "when the `module` directive doesn't start with `./` \
-                 then it's interpreted as an NPM package which requires \
-                 a `version` to be specified as well, try using \
-                 #[wasm_bindgen(module = \"...\", version = \"...\")]"
-            ),
-            (&None, &Some(_)) => {
-                panic!(
-                    "the #[wasm_bindgen(version = \"...\")] attribute can only \
-                     be used when `module = \"...\"` is also specified"
-                );
-            }
-            (&None, &None) => {}
-        }
         Ok(shared::Import {
             module: self.module.clone(),
-            version: self.version.clone(),
             js_namespace: self.js_namespace.as_ref().map(|s| s.to_string()),
             kind: self.kind.shared(),
         })

crates/backend/src/util.rs

@@ -94,7 +94,6 @@ pub fn ident_ty(ident: Ident) -> syn::Type {
 pub fn wrap_import_function(function: ast::ImportFunction) -> ast::Import {
     ast::Import {
         module: None,
-        version: None,
         js_namespace: None,
         kind: ast::ImportKind::Function(function),
     }