Fix Call Generics & FnOnce macro hygiene (#2437)

* Fix Call Generics & FnOnce macro hygiene.

* Add a failure case as well.

* Remove a unused struct in test case.

* Update packages/yew-macro/tests/hook_attr/hook-const-generic-pass.rs

Co-authored-by: Muhammad Hamza <muhammadhamza1311@gmail.com>

packages/yew-macro/src/hook/mod.rs

@@ -1,9 +1,9 @@
 use proc_macro2::{Span, TokenStream};
 use proc_macro_error::emit_error;
-use quote::quote;
+use quote::{quote, ToTokens};
 use syn::parse::{Parse, ParseStream};
 use syn::visit_mut;
-use syn::{parse_file, Ident, ItemFn, LitStr, ReturnType, Signature};
+use syn::{parse_file, GenericParam, Ident, ItemFn, LitStr, ReturnType, Signature};
 
 mod body;
 mod lifetime;
@@ -98,6 +98,19 @@ When used in function components and hooks, this hook is equivalent to:
     let output_type = &hook_sig.output_type;
 
     let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+    let call_generics = {
+        let mut generics = generics.clone();
+
+        // We need to filter out lifetimes.
+        generics.params = generics
+            .params
+            .into_iter()
+            .filter(|m| !matches!(m, GenericParam::Lifetime(_)))
+            .collect();
+
+        let (_impl_generics, ty_generics, _where_clause) = generics.split_for_impl();
+        ty_generics.as_turbofish().to_token_stream()
+    };
 
     let ctx_ident = Ident::new("ctx", Span::mixed_site());
 
@@ -120,13 +133,13 @@ When used in function components and hooks, this hook is equivalent to:
         let hook_lifetime_plus = quote! { #hook_lifetime + };
 
         let boxed_inner_ident = Ident::new("boxed_inner", Span::mixed_site());
-        let boxed_fn_type = quote! { ::std::boxed::Box<dyn #hook_lifetime_plus FnOnce(&mut ::yew::functional::HookContext) #inner_fn_rt> };
+        let boxed_fn_type = quote! { ::std::boxed::Box<dyn #hook_lifetime_plus ::std::ops::FnOnce(&mut ::yew::functional::HookContext) #inner_fn_rt> };
 
         // We need boxing implementation for `impl Trait` arguments.
         quote! {
             let #boxed_inner_ident = ::std::boxed::Box::new(
                     move |#ctx_ident: &mut ::yew::functional::HookContext| #inner_fn_rt {
-                        #inner_fn_ident (#ctx_ident, #(#input_args,)*)
+                        #inner_fn_ident #call_generics (#ctx_ident, #(#input_args,)*)
                     }
                 ) as #boxed_fn_type;
 
@@ -138,8 +151,6 @@ When used in function components and hooks, this hook is equivalent to:
         let args_ident = Ident::new("args", Span::mixed_site());
         let hook_struct_name = Ident::new("HookProvider", Span::mixed_site());
 
-        let call_generics = ty_generics.as_turbofish();
-
         let phantom_types = hook_sig.phantom_types();
         let phantom_lifetimes = hook_sig.phantom_lifetimes();
 
@@ -155,7 +166,7 @@ When used in function components and hooks, this hook is equivalent to:
                 fn run(mut self, #ctx_ident: &mut ::yew::functional::HookContext) -> Self::Output {
                     let (#(#input_args,)*) = self.#args_ident;
 
-                    #inner_fn_ident(#ctx_ident, #(#input_args,)*)
+                    #inner_fn_ident #call_generics (#ctx_ident, #(#input_args,)*)
                 }
             }
 

packages/yew-macro/tests/hook_attr/hook-call-generics-pass.rs

@@ -0,0 +1,12 @@
+use yew::prelude::*;
+
+#[hook]
+fn use_reducer_default_action<T>() -> T::Action
+where
+    T: Reducible + 'static,
+    T::Action: Default + 'static,
+{
+    T::Action::default()
+}
+
+fn main() {}

packages/yew-macro/tests/hook_attr/hook-const-generic-pass.rs

@@ -0,0 +1,8 @@
+#![no_implicit_prelude]
+
+#[::yew::prelude::hook]
+fn use_a_const<const N: u32>() -> u32 {
+    N
+}
+
+fn main() {}

packages/yew-macro/tests/hook_attr/hook-impl-trait-pass.rs

@@ -0,0 +1,9 @@
+// we need to re-test the macro hygiene here as it uses a different implementation for impl traits.
+#![no_implicit_prelude]
+
+#[::yew::prelude::hook]
+fn use_some_string(a: impl ::std::convert::Into<::std::string::String>) -> ::std::string::String {
+    a.into()
+}
+
+fn main() {}

packages/yew-macro/tests/hook_attr/hook-lifetime-pass.rs

@@ -0,0 +1,8 @@
+use yew::prelude::*;
+
+#[hook]
+fn use_as_is<'a>(input: &'a ()) -> &'a () {
+    input
+}
+
+fn main() {}

packages/yew-macro/tests/hook_attr/hook_location-fail.rs

@@ -0,0 +1,39 @@
+use yew::prelude::*;
+
+#[derive(Debug, PartialEq, Clone)]
+struct Ctx;
+
+#[hook]
+fn use_some_html() -> Html {
+    if let Some(_m) = use_context::<Ctx>() {
+        use_context::<Ctx>().unwrap();
+        todo!()
+    }
+
+    let _ = || {
+        use_context::<Ctx>().unwrap();
+        todo!()
+    };
+
+    for _ in 0..10 {
+        use_context::<Ctx>().unwrap();
+    }
+
+    while let Some(_m) = use_context::<Ctx>() {
+        use_context::<Ctx>().unwrap();
+    }
+
+    match use_context::<Ctx>() {
+        Some(_) => use_context::<Ctx>(),
+        None => {
+            todo!()
+        }
+    }
+
+    loop {
+        use_context::<Ctx>().unwrap();
+        todo!()
+    }
+}
+
+fn main() {}

packages/yew-macro/tests/hook_attr/hook_location-fail.stderr

@@ -0,0 +1,69 @@
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+ --> tests/hook_attr/hook_location-fail.rs:9:9
+  |
+9 |         use_context::<Ctx>().unwrap();
+  |         ^^^^^^^^^^^
+
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+  --> tests/hook_attr/hook_location-fail.rs:14:9
+   |
+14 |         use_context::<Ctx>().unwrap();
+   |         ^^^^^^^^^^^
+
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+  --> tests/hook_attr/hook_location-fail.rs:19:9
+   |
+19 |         use_context::<Ctx>().unwrap();
+   |         ^^^^^^^^^^^
+
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+  --> tests/hook_attr/hook_location-fail.rs:22:26
+   |
+22 |     while let Some(_m) = use_context::<Ctx>() {
+   |                          ^^^^^^^^^^^
+
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+  --> tests/hook_attr/hook_location-fail.rs:23:9
+   |
+23 |         use_context::<Ctx>().unwrap();
+   |         ^^^^^^^^^^^
+
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+  --> tests/hook_attr/hook_location-fail.rs:27:20
+   |
+27 |         Some(_) => use_context::<Ctx>(),
+   |                    ^^^^^^^^^^^
+
+error: hooks cannot be called at this position.
+
+  = help: move hooks to the top-level of your function.
+  = note: see: https://yew.rs/docs/next/concepts/function-components/introduction#hooks
+
+  --> tests/hook_attr/hook_location-fail.rs:34:9
+   |
+34 |         use_context::<Ctx>().unwrap();
+   |         ^^^^^^^^^^^

packages/yew-macro/tests/hook_attr/hook_location-pass.rs

@@ -0,0 +1,30 @@
+#![no_implicit_prelude]
+
+#[derive(
+    ::std::prelude::rust_2021::Debug,
+    ::std::prelude::rust_2021::PartialEq,
+    ::std::prelude::rust_2021::Clone,
+)]
+struct Ctx;
+
+#[::yew::prelude::hook]
+fn use_some_html() -> ::yew::prelude::Html {
+    ::yew::prelude::use_context::<Ctx>().unwrap();
+
+    if let ::std::prelude::rust_2021::Some(_m) = ::yew::prelude::use_context::<Ctx>() {
+        ::std::todo!()
+    }
+
+    let _ctx = { ::yew::prelude::use_context::<Ctx>() };
+
+    match ::yew::prelude::use_context::<Ctx>() {
+        ::std::prelude::rust_2021::Some(_) => {
+            ::std::todo!()
+        }
+        ::std::prelude::rust_2021::None => {
+            ::std::todo!()
+        }
+    }
+}
+
+fn main() {}

packages/yew-macro/tests/hook_attr_test.rs

@@ -0,0 +1,7 @@
+#[allow(dead_code)]
+#[rustversion::attr(stable(1.56), test)]
+fn tests() {
+    let t = trybuild::TestCases::new();
+    t.pass("tests/hook_attr/*-pass.rs");
+    t.compile_fail("tests/hook_attr/*-fail.rs");
+}