From dc8d209f2966ce756b81239a86973c5b4a272e23 Mon Sep 17 00:00:00 2001 From: David Tolnay Date: Fri, 1 Jul 2016 22:34:15 -0700 Subject: [PATCH] Remove filter no longer necessary for rustc >=1.7 --- serde_codegen/src/bound.rs | 42 -------------------------------------- 1 file changed, 42 deletions(-) diff --git a/serde_codegen/src/bound.rs b/serde_codegen/src/bound.rs index 259b2427..72737ed5 100644 --- a/serde_codegen/src/bound.rs +++ b/serde_codegen/src/bound.rs @@ -1,5 +1,3 @@ -use std::collections::HashSet; - use aster::AstBuilder; use syntax::ast; @@ -63,8 +61,6 @@ pub fn with_bound( item.body.all_fields() .filter(|&field| filter(&field.attrs)) .map(|field| &field.ty) - // TODO this filter can be removed later, see comment on function - .filter(|ty| contains_generic(ty, generics)) .filter(|ty| !contains_recursion(ty, item.ident)) .map(|ty| strip_reference(ty)) .map(|ty| builder.where_predicate() @@ -76,44 +72,6 @@ pub fn with_bound( .build() } -// Rust <1.7 enforces that `where` clauses involve generic type parameters. The -// corresponding compiler error is E0193. It is no longer enforced in Rust >=1.7 -// so this filtering can be removed in the future when we stop supporting <1.7. -// -// E0193 means we must not generate a `where` clause like `i32: Serialize` -// because even though i32 implements Serialize, i32 is not a generic type -// parameter. Clauses like `T: Serialize` and `Option: Serialize` are okay. -// This function decides whether a given type references any of the generic type -// parameters in the input `Generics`. -fn contains_generic(ty: &ast::Ty, generics: &ast::Generics) -> bool { - struct FindGeneric<'a> { - generic_names: &'a HashSet, - found_generic: bool, - } - impl<'a, 'v> visit::Visitor<'v> for FindGeneric<'a> { - fn visit_path(&mut self, path: &'v ast::Path, _id: ast::NodeId) { - if !path.global - && path.segments.len() == 1 - && self.generic_names.contains(&path.segments[0].identifier.name) { - self.found_generic = true; - } else { - visit::walk_path(self, path); - } - } - } - - let generic_names: HashSet<_> = generics.ty_params.iter() - .map(|ty_param| ty_param.ident.name) - .collect(); - - let mut visitor = FindGeneric { - generic_names: &generic_names, - found_generic: false, - }; - visit::walk_ty(&mut visitor, ty); - visitor.found_generic -} - // We do not attempt to generate any bounds based on field types that are // directly recursive, as in: //