Make rustc stop complaining about unused `Box::from_raw`s

[ldk-c-bindings] / c-bindings-gen / src / blocks.rs

diff --git a/c-bindings-gen/src/blocks.rs b/c-bindings-gen/src/blocks.rs
index 5034b0902c1140fb0002f2098971578aee87aa5e..28f30026ed0810ef0263be3a8b4636a234d59b54 100644 (file)
--- a/c-bindings-gen/src/blocks.rs
+++ b/c-bindings-gen/src/blocks.rs
@@ -250,7 +250,7 @@ pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, in
        writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
        writeln!(w, "\tfn drop(&mut self) {{").unwrap();
        writeln!(w, "\t\tif self.datalen == 0 {{ return; }}").unwrap();
-       writeln!(w, "\t\tunsafe {{ Box::from_raw(core::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
+       writeln!(w, "\t\tlet _ = unsafe {{ Box::from_raw(core::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
        writeln!(w, "\t}}").unwrap();
        writeln!(w, "}}").unwrap();
        if clonable {
@@ -460,7 +460,7 @@ fn writeln_docs_impl<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribut
                        },
                }
        }
-       if let Some((types, generics, inp, outp, field)) = method_args_ret {
+       if let Some((types, generics, inp, outp, field_ty)) = method_args_ret {
                let mut nullable_found = false;
                for (name, inp) in inp {
                        if types.skip_arg(inp, generics) { continue; }
@@ -491,8 +491,13 @@ fn writeln_docs_impl<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribut
                        nullable_found = true;
                        writeln!(w, "{}/// Note that the return value (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
                }
+               let field = field_ty.map(|ty| generics.resolve_type(ty));
                if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = field {
                        if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
+                               let resolved_path = types.resolve_path(path, generics);
+                               if types.crate_types.opaques.get(&resolved_path).is_some() {
+                                       writeln!(w, "{}/// Note that this field is expected to be a reference.", prefix).unwrap();
+                               }
                                types.is_path_transparent_container(path, generics, true)
                        } else { false }
                } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = field {
@@ -571,7 +576,7 @@ pub fn write_method_params<W: std::io::Write>(w: &mut W, sig: &syn::Signature, t
                                        },
                                        _ => unimplemented!(),
                                }
-                               w.write(&c_type).unwrap();
+                               w.write_all(&c_type).unwrap();
                        }
                }
        }
@@ -742,30 +747,58 @@ pub fn write_method_call_params<W: std::io::Write>(w: &mut W, sig: &syn::Signatu
 
 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 /// greater-than symbols, if any generic parameters are defined.
-pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
+pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, generics_impld: &syn::PathArguments, types: &TypeResolver, concrete_lifetimes: bool) {
        let mut gen_types = GenericTypes::new(None);
        assert!(gen_types.learn_generics(generics, types));
-       if !generics.params.is_empty() {
-               write!(w, "<").unwrap();
-               for (idx, generic) in generics.params.iter().enumerate() {
-                       match generic {
-                               syn::GenericParam::Type(type_param) => {
-                                       write!(w, "{}", if idx != 0 { ", " } else { "" }).unwrap();
-                                       let type_ident = &type_param.ident;
-                                       types.write_c_type_in_generic_param(w, &syn::parse_quote!(#type_ident), Some(&gen_types), false);
-                               },
-                               syn::GenericParam::Lifetime(lt) => {
-                                       if concrete_lifetimes {
-                                               write!(w, "'static").unwrap();
-                                       } else {
-                                               write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
+       if generics.params.is_empty() { return; }
+       for generic in generics.params.iter() {
+               match generic {
+                       syn::GenericParam::Type(type_param) => {
+                               for bound in type_param.bounds.iter() {
+                                       match bound {
+                                               syn::TypeParamBound::Trait(t) => {
+                                                       if let Some(trait_bound) = types.maybe_resolve_path(&t.path, None) {
+                                                               if types.skip_path(&trait_bound) {
+                                                                       // Just hope rust deduces generic params if some bounds are skipable.
+                                                                       return;
+                                                               }
+                                                       }
+                                               }
+                                               _ => {},
                                        }
-                               },
-                               _ => unimplemented!(),
+                               }
                        }
+                       _ => {},
+               }
+       }
+
+       write!(w, "<").unwrap();
+       for (idx, generic) in generics.params.iter().enumerate() {
+               match generic {
+                       syn::GenericParam::Type(type_param) => {
+                               write!(w, "{}", if idx != 0 { ", " } else { "" }).unwrap();
+                               let type_ident = &type_param.ident;
+                               if types.understood_c_type(&syn::parse_quote!(#type_ident), Some(&gen_types)) {
+                                       types.write_c_type_in_generic_param(w, &syn::parse_quote!(#type_ident), Some(&gen_types), false);
+                               } else {
+                                       if let syn::PathArguments::AngleBracketed(args) = generics_impld {
+                                               if let syn::GenericArgument::Type(ty) = &args.args[idx] {
+                                                       types.write_c_type_in_generic_param(w, &ty, Some(&gen_types), false);
+                                               }
+                                       }
+                               }
+                       },
+                       syn::GenericParam::Lifetime(lt) => {
+                               if concrete_lifetimes {
+                                       write!(w, "'static").unwrap();
+                               } else {
+                                       write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
+                               }
+                       },
+                       _ => unimplemented!(),
                }
-               write!(w, ">").unwrap();
        }
+       write!(w, ">").unwrap();
 }
 
 pub fn maybe_write_lifetime_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver) {