83 lines
2.4 KiB
Rust
83 lines
2.4 KiB
Rust
use proc_macro2::TokenStream;
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use quote::ToTokens;
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use std::collections::btree_map::Entry;
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use std::collections::{BTreeMap as Map, BTreeSet as Set};
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use syn::punctuated::Punctuated;
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use syn::{parse_quote, GenericArgument, Generics, Ident, PathArguments, Token, Type, WhereClause};
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pub struct ParamsInScope<'a> {
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names: Set<&'a Ident>,
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}
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impl<'a> ParamsInScope<'a> {
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pub fn new(generics: &'a Generics) -> Self {
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ParamsInScope {
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names: generics.type_params().map(|param| ¶m.ident).collect(),
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}
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}
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pub fn intersects(&self, ty: &Type) -> bool {
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let mut found = false;
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crawl(self, ty, &mut found);
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found
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}
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}
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fn crawl(in_scope: &ParamsInScope, ty: &Type, found: &mut bool) {
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if let Type::Path(ty) = ty {
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if ty.qself.is_none() {
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if let Some(ident) = ty.path.get_ident() {
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if in_scope.names.contains(ident) {
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*found = true;
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}
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}
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}
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for segment in &ty.path.segments {
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if let PathArguments::AngleBracketed(arguments) = &segment.arguments {
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for arg in &arguments.args {
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if let GenericArgument::Type(ty) = arg {
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crawl(in_scope, ty, found);
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}
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}
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}
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}
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}
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}
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pub struct InferredBounds {
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bounds: Map<String, (Set<String>, Punctuated<TokenStream, Token![+]>)>,
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order: Vec<TokenStream>,
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}
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impl InferredBounds {
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pub fn new() -> Self {
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InferredBounds {
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bounds: Map::new(),
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order: Vec::new(),
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}
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}
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pub fn insert(&mut self, ty: impl ToTokens, bound: impl ToTokens) {
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let ty = ty.to_token_stream();
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let bound = bound.to_token_stream();
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let entry = self.bounds.entry(ty.to_string());
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if let Entry::Vacant(_) = entry {
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self.order.push(ty);
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}
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let (set, tokens) = entry.or_default();
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if set.insert(bound.to_string()) {
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tokens.push(bound);
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}
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}
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pub fn augment_where_clause(&self, generics: &Generics) -> WhereClause {
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let mut generics = generics.clone();
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let where_clause = generics.make_where_clause();
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for ty in &self.order {
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let (_set, bounds) = &self.bounds[&ty.to_string()];
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where_clause.predicates.push(parse_quote!(#ty: #bounds));
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}
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generics.where_clause.unwrap()
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}
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}
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