module: Make generic work for consts

Summary:
The easiest one of consts/attrs/funcs, just need to pass the generics down to the inner builder function

This breaks the one place that was putting `<'v>` on the `fn globals_builder()`, but that's completely wrong anyway

Reviewed By: ndmitchell

Differential Revision: D73726004

fbshipit-source-id: 7567478c297f9d811e328af73fff1d98e618a24f

Author: JakobDegen

starlark/src/tests/derive/module.rs

@@ -17,6 +17,7 @@
 
 mod basic;
 mod default_value;
+mod generic;
 mod kwargs;
 mod methods;
 mod named_positional;

starlark/src/tests/derive/module/generic.rs

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2018 The Starlark in Rust Authors.
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use starlark_derive::starlark_module;
+
+use crate as starlark;
+use crate::assert::Assert;
+use crate::environment::GlobalsBuilder;
+
+#[starlark_module]
+fn generic_builder<T: Default, U>(globals: &mut GlobalsBuilder)
+where
+    U: std::fmt::Display + Default,
+{
+    const MY_STR: &str = &U::default().to_string();
+}
+
+#[test]
+fn test_generic_builder() {
+    let mut a = Assert::new();
+    a.globals_add(generic_builder::<u8, u8>);
+    a.eq("\"0\"", "MY_STR");
+}

starlark/src/tests/uncategorized.rs

@@ -743,7 +743,7 @@ fn test_label_assign() {
     }
 
     #[starlark_module]
-    fn module<'v>(builder: &mut GlobalsBuilder) {
+    fn module(builder: &mut GlobalsBuilder) {
         fn wrapper<'v>(heap: &'v Heap) -> anyhow::Result<Value<'v>> {
             Ok(heap.alloc_complex(Wrapper(RefCell::new(SmallMap::new()))))
         }

starlark_derive/src/module/render.rs

@@ -68,11 +68,13 @@ fn render_impl(x: StarModule) -> syn::Result<syn::ItemFn> {
             }
         },
     };
+    let turbo = input.sig.generics.split_for_impl().1;
+    let turbo = turbo.as_turbofish();
     input.block = syn::parse_quote! {
         {
             #inner_fn
             static RES: starlark::environment::#statics = starlark::environment::#statics::new();
-            RES.populate(build, globals_builder);
+            RES.populate(build #turbo, globals_builder);
         }
     };
     Ok(input)