mirror of https://github.com/rust-lang/rust
139 lines
3.4 KiB
Rust
139 lines
3.4 KiB
Rust
//@ run-pass
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#![allow(dead_code)]
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#![allow(unused_imports)]
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// Test a sample usage pattern for regions. Makes use of the
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// following features:
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//
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// - Multiple lifetime parameters
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// - Arenas
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#![feature(rustc_private)]
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extern crate rustc_arena;
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// Necessary to pull in object code as the rest of the rustc crates are shipped only as rmeta
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// files.
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#[allow(unused_extern_crates)]
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extern crate rustc_driver;
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use TypeStructure::{TypeInt, TypeFunction};
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use AstKind::{ExprInt, ExprVar, ExprLambda};
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use rustc_arena::TypedArena;
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use std::collections::HashMap;
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use std::mem;
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type Type<'tcx> = &'tcx TypeStructure<'tcx>;
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#[derive(Copy, Clone, Debug)]
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enum TypeStructure<'tcx> {
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TypeInt,
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TypeFunction(Type<'tcx>, Type<'tcx>),
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}
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impl<'tcx> PartialEq for TypeStructure<'tcx> {
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fn eq(&self, other: &TypeStructure<'tcx>) -> bool {
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match (*self, *other) {
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(TypeInt, TypeInt) => true,
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(TypeFunction(s_a, s_b), TypeFunction(o_a, o_b)) => *s_a == *o_a && *s_b == *o_b,
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_ => false
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}
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}
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}
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impl<'tcx> Eq for TypeStructure<'tcx> {}
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type TyArena<'tcx> = TypedArena<TypeStructure<'tcx>>;
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type AstArena<'ast> = TypedArena<AstStructure<'ast>>;
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struct TypeContext<'tcx, 'ast> {
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ty_arena: &'tcx TyArena<'tcx>,
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types: Vec<Type<'tcx>> ,
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type_table: HashMap<NodeId, Type<'tcx>>,
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ast_arena: &'ast AstArena<'ast>,
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ast_counter: usize,
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}
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impl<'tcx,'ast> TypeContext<'tcx, 'ast> {
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fn new(ty_arena: &'tcx TyArena<'tcx>, ast_arena: &'ast AstArena<'ast>)
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-> TypeContext<'tcx, 'ast> {
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TypeContext { ty_arena: ty_arena,
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types: Vec::new(),
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type_table: HashMap::new(),
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ast_arena: ast_arena,
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ast_counter: 0 }
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}
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fn add_type(&mut self, s: TypeStructure<'tcx>) -> Type<'tcx> {
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for &ty in &self.types {
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if *ty == s {
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return ty;
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}
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}
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let ty = self.ty_arena.alloc(s);
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self.types.push(ty);
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ty
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}
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fn set_type(&mut self, id: NodeId, ty: Type<'tcx>) -> Type<'tcx> {
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self.type_table.insert(id, ty);
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ty
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}
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fn ast(&mut self, a: AstKind<'ast>) -> Ast<'ast> {
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let id = self.ast_counter;
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self.ast_counter += 1;
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self.ast_arena.alloc(AstStructure { id: NodeId {id:id}, kind: a })
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}
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}
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#[derive(Copy, Clone, PartialEq, Eq, Hash)]
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struct NodeId {
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id: usize
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}
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type Ast<'ast> = &'ast AstStructure<'ast>;
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#[derive(Copy, Clone)]
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struct AstStructure<'ast> {
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id: NodeId,
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kind: AstKind<'ast>
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}
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#[derive(Copy, Clone)]
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enum AstKind<'ast> {
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ExprInt,
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ExprVar(usize),
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ExprLambda(Ast<'ast>),
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}
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fn compute_types<'tcx,'ast>(tcx: &mut TypeContext<'tcx,'ast>,
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ast: Ast<'ast>) -> Type<'tcx>
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{
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match ast.kind {
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ExprInt | ExprVar(_) => {
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let ty = tcx.add_type(TypeInt);
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tcx.set_type(ast.id, ty)
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}
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ExprLambda(ast) => {
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let arg_ty = tcx.add_type(TypeInt);
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let body_ty = compute_types(tcx, ast);
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let lambda_ty = tcx.add_type(TypeFunction(arg_ty, body_ty));
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tcx.set_type(ast.id, lambda_ty)
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}
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}
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}
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pub fn main() {
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let ty_arena = TypedArena::default();
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let ast_arena = TypedArena::default();
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let mut tcx = TypeContext::new(&ty_arena, &ast_arena);
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let ast = tcx.ast(ExprInt);
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let ty = compute_types(&mut tcx, ast);
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assert_eq!(*ty, TypeInt);
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}
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