WIP implementing handling #[cfg] and #[cfg_attr] in proc macro inputs

crates/fayalite-proc-macros-impl/src/process_cfg.rs

@@ -271,60 +271,27 @@ impl<T: Process<P>, P: Phase> Process<P> for Box<T> {
     }
 }
 
-trait ProcessVecElement {
-    const REMOVE_ELEMENTS: bool;
-}
-
-impl ProcessVecElement for syn::Stmt {
-    const REMOVE_ELEMENTS: bool = true;
-}
-
-impl ProcessVecElement for syn::ForeignItem {
-    const REMOVE_ELEMENTS: bool = true;
-}
-
-impl ProcessVecElement for syn::ImplItem {
-    const REMOVE_ELEMENTS: bool = true;
-}
-
-impl ProcessVecElement for syn::Item {
-    const REMOVE_ELEMENTS: bool = true;
-}
-
-impl ProcessVecElement for syn::TraitItem {
-    const REMOVE_ELEMENTS: bool = true;
-}
-
-impl<T: Process<P> + ProcessVecElement, P: Phase> Process<P> for Vec<T> {
-    fn process(self, state: &mut State<P>) -> Option<Output<Self, P>> {
-        let mut output = Output::new(Vec::new());
-        for value in self {
-            if let Some(value) = value.process(state) {
-                output = (output, value).call(|(mut output, value)| {
-                    output.push(value);
-                    output
-                });
-            } else if !T::REMOVE_ELEMENTS {
-                return None;
-            }
-        }
-        Some(output)
-    }
-}
-
 trait ProcessOption {
     /// if a configured-off value causes this value to be `None` instead of propagating the configuring-off
     const REMOVE_VALUE: bool;
 }
 
-impl ProcessOption for syn::WhereClause {
-    const REMOVE_VALUE: bool = true;
+impl ProcessOption for Token![<] {
+    const REMOVE_VALUE: bool = false;
 }
 
-impl ProcessOption for syn::ImplRestriction {
+impl ProcessOption for Token![>] {
     const REMOVE_VALUE: bool = false;
 }
 
+impl ProcessOption for Token![=] {
+    const REMOVE_VALUE: bool = false;
+}
+
+impl ProcessOption for syn::WhereClause {
+    const REMOVE_VALUE: bool = true;
+}
+
 impl ProcessOption for (Token![=], syn::Expr) {
     const REMOVE_VALUE: bool = true;
 }
@@ -333,22 +300,34 @@ impl ProcessOption for (Token![as], Ident) {
     const REMOVE_VALUE: bool = true;
 }
 
+impl ProcessOption for Token![unsafe] {
+    const REMOVE_VALUE: bool = true;
+}
+
+impl ProcessOption for Token![default] {
+    const REMOVE_VALUE: bool = true;
+}
+
+impl ProcessOption for Token![const] {
+    const REMOVE_VALUE: bool = true;
+}
+
+impl ProcessOption for Token![async] {
+    const REMOVE_VALUE: bool = true;
+}
+
 impl ProcessOption for (Option<Token![!]>, syn::Path, Token![for]) {
     const REMOVE_VALUE: bool = false;
 }
 
+impl ProcessOption for syn::Abi {
+    const REMOVE_VALUE: bool = false;
+}
+
 impl ProcessOption for syn::Variadic {
     const REMOVE_VALUE: bool = true;
 }
 
-impl ProcessOption for (Box<syn::Pat>, Token![:]) {
-    const REMOVE_VALUE: bool = false;
-}
-
-impl ProcessOption for (syn::token::Brace, Vec<syn::Item>) {
-    const REMOVE_VALUE: bool = false;
-}
-
 impl<T: Process<P> + ProcessOption, P: Phase> Process<P> for Option<T> {
     fn process(self, state: &mut State<P>) -> Option<Output<Self, P>> {
         if let Some(this) = self {
@@ -424,8 +403,19 @@ impl ProcessPunctuatedElement for syn::FnArg {
     const REMOVE_ELEMENTS: bool = true;
 }
 
-impl ProcessPunctuatedElement for syn::TypeParamBound {
-    const REMOVE_ELEMENTS: bool = true;
+impl<P: Phase> Process<P> for Vec<syn::Stmt> {
+    fn process(self, state: &mut State<P>) -> Option<Output<Self, P>> {
+        let mut output = Output::new(Vec::new());
+        for value in self {
+            if let Some(value) = value.process(state) {
+                output = (output, value).call(|(mut output, value)| {
+                    output.push(value);
+                    output
+                });
+            }
+        }
+        Some(output)
+    }
 }
 
 impl<T: Process<P>, U: Process<P>, P: Phase> Process<P> for (T, U) {
@@ -454,17 +444,12 @@ macro_rules! process_no_op {
                 Some(Output::new(self))
             }
         }
-
-        impl ProcessOption for $ty {
-            const REMOVE_VALUE: bool = false;
-        }
     };
 }
 
 process_no_op!(syn::Visibility);
 process_no_op!(syn::Lifetime);
 process_no_op!(syn::Abi);
-process_no_op!(syn::StaticMutability);
 process_no_op!(Token![as]);
 process_no_op!(Token![async]);
 process_no_op!(Token![auto]);
@@ -510,53 +495,14 @@ process_no_op!(Token![use]);
 process_no_op!(Token![where]);
 process_no_op!(Token![while]);
 process_no_op!(Token![yield]);
-process_no_op!(Token![&]);
-process_no_op!(Token![&&]);
-process_no_op!(Token![&=]);
-process_no_op!(Token![@]);
-process_no_op!(Token![^]);
-process_no_op!(Token![^=]);
 process_no_op!(Token![:]);
-process_no_op!(Token![,]);
-process_no_op!(Token![$]);
-process_no_op!(Token![.]);
-process_no_op!(Token![..]);
-process_no_op!(Token![...]);
-process_no_op!(Token![..=]);
-process_no_op!(Token![=]);
-process_no_op!(Token![==]);
-process_no_op!(Token![=>]);
-process_no_op!(Token![>=]);
-process_no_op!(Token![>]);
-process_no_op!(Token![<-]);
-process_no_op!(Token![<=]);
-process_no_op!(Token![<]);
-process_no_op!(Token![-]);
-process_no_op!(Token![-=]);
-process_no_op!(Token![!=]);
-process_no_op!(Token![!]);
-process_no_op!(Token![|]);
-process_no_op!(Token![|=]);
-process_no_op!(Token![||]);
 process_no_op!(Token![::]);
-process_no_op!(Token![%]);
-process_no_op!(Token![%=]);
-process_no_op!(Token![+]);
-process_no_op!(Token![+=]);
-process_no_op!(Token![#]);
-process_no_op!(Token![?]);
-process_no_op!(Token![->]);
 process_no_op!(Token![;]);
-process_no_op!(Token![<<]);
-process_no_op!(Token![<<=]);
-process_no_op!(Token![>>]);
-process_no_op!(Token![>>=]);
-process_no_op!(Token![/]);
-process_no_op!(Token![/=]);
-process_no_op!(Token![*]);
-process_no_op!(Token![*=]);
-process_no_op!(Token![~]);
-process_no_op!(Token![_]);
+process_no_op!(Token![=]);
+process_no_op!(Token![?]);
+process_no_op!(Token![..]);
+process_no_op!(Token![<]);
+process_no_op!(Token![>]);
 process_no_op!(syn::token::Brace);
 process_no_op!(syn::token::Bracket);
 process_no_op!(syn::token::Paren);
@@ -1543,71 +1489,6 @@ process_enum! {
     }
 }
 
-process_enum! {
-    syn::Pat {
-        Const,
-        Ident,
-        Lit,
-        Macro,
-        Or,
-        Paren,
-        Path,
-        Range,
-        Reference,
-        Rest,
-        Slice,
-        Struct,
-        Tuple,
-        TupleStruct,
-        Type,
-        Wild,
-        #[no_op]
-        _,
-    }
-}
-
-process_enum! {
-    syn::ForeignItem {
-        Fn,
-        Static,
-        Type,
-        Macro,
-        #[no_op]
-        _,
-    }
-}
-
-process_enum! {
-    syn::ImplItem {
-        Const,
-        Fn,
-        Type,
-        Macro,
-        #[no_op]
-        _,
-    }
-}
-
-process_enum! {
-    syn::TypeParamBound {
-        Trait,
-        Lifetime,
-        #[no_op]
-        _,
-    }
-}
-
-process_enum! {
-    syn::TraitItem {
-        Const,
-        Fn,
-        Type,
-        Macro,
-        #[no_op]
-        _,
-    }
-}
-
 impl<P: Phase> Process<P> for syn::ReturnType {
     fn process(self, state: &mut State<P>) -> Option<Output<Self, P>> {
         match self {
@@ -1673,12 +1554,6 @@ impl<P: Phase> Process<P> for TopItem {
     }
 }
 
-impl<P: Phase> Process<P> for syn::ImplRestriction {
-    fn process(self, _state: &mut State<P>) -> Option<Output<Self, P>> {
-        todo!("ImplRestriction is an uninhabited type as of writing, blocked on syn implementing impl restrictions")
-    }
-}
-
 pub(crate) fn process_cfgs(item: syn::Item, cfgs: Cfgs<bool>) -> syn::Result<Option<syn::Item>> {
     let mut state = State::<ProcessCfgsPhase> {
         cfgs,