683 lines
25 KiB
Rust
683 lines
25 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use core::prelude::*;
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use middle::freevars::freevar_entry;
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use middle::freevars;
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use middle::lint::{non_implicitly_copyable_typarams, implicit_copies};
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use middle::liveness;
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use middle::pat_util;
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use middle::ty::{CopyValue, MoveValue, ReadValue};
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use middle::ty::{Kind, kind_copyable, kind_noncopyable, kind_const};
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use middle::ty;
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use middle::typeck;
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use middle;
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use util::ppaux::{ty_to_str, tys_to_str};
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use core::option;
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use core::str;
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use core::vec;
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use std::map::HashMap;
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use syntax::ast::*;
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use syntax::codemap::span;
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use syntax::print::pprust::expr_to_str;
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use syntax::{visit, ast_util};
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// Kind analysis pass.
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//
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// There are several kinds defined by various operations. The most restrictive
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// kind is noncopyable. The noncopyable kind can be extended with any number
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// of the following attributes.
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//
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// send: Things that can be sent on channels or included in spawned closures.
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// copy: Things that can be copied.
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// const: Things thare are deeply immutable. They are guaranteed never to
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// change, and can be safely shared without copying between tasks.
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// owned: Things that do not contain borrowed pointers.
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//
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// Send includes scalar types as well as classes and unique types containing
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// only sendable types.
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//
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// Copy includes boxes, closure and unique types containing copyable types.
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//
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// Const include scalar types, things without non-const fields, and pointers
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// to const things.
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//
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// This pass ensures that type parameters are only instantiated with types
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// whose kinds are equal or less general than the way the type parameter was
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// annotated (with the `send`, `copy` or `const` keyword).
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//
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// It also verifies that noncopyable kinds are not copied. Sendability is not
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// applied, since none of our language primitives send. Instead, the sending
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// primitives in the stdlib are explicitly annotated to only take sendable
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// types.
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const try_adding: &str = "Try adding a move";
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fn kind_to_str(k: Kind) -> ~str {
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let mut kinds = ~[];
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if ty::kind_lteq(kind_const(), k) {
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kinds.push(~"const");
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}
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if ty::kind_can_be_copied(k) {
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kinds.push(~"copy");
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}
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if ty::kind_can_be_sent(k) {
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kinds.push(~"owned");
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} else if ty::kind_is_durable(k) {
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kinds.push(~"&static");
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}
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str::connect(kinds, ~" ")
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}
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type rval_map = HashMap<node_id, ()>;
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type ctx = {tcx: ty::ctxt,
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method_map: typeck::method_map,
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last_use_map: liveness::last_use_map,
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current_item: node_id};
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fn check_crate(tcx: ty::ctxt,
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method_map: typeck::method_map,
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last_use_map: liveness::last_use_map,
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crate: @crate) {
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let ctx = {tcx: tcx,
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method_map: method_map,
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last_use_map: last_use_map,
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current_item: -1};
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let visit = visit::mk_vt(@visit::Visitor {
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visit_arm: check_arm,
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visit_expr: check_expr,
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visit_stmt: check_stmt,
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visit_block: check_block,
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visit_fn: check_fn,
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visit_ty: check_ty,
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visit_item: fn@(i: @item, cx: ctx, v: visit::vt<ctx>) {
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visit::visit_item(i, {current_item: i.id,.. cx}, v);
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},
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.. *visit::default_visitor()
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});
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visit::visit_crate(*crate, ctx, visit);
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tcx.sess.abort_if_errors();
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}
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// bool flag is only used for checking closures,
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// where it refers to whether a var is 'move' in the
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// capture clause
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type check_fn = fn@(ctx, node_id, Option<@freevar_entry>,
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bool, ty::t, sp: span);
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// Yields the appropriate function to check the kind of closed over
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// variables. `id` is the node_id for some expression that creates the
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// closure.
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fn with_appropriate_checker(cx: ctx, id: node_id, b: fn(check_fn)) {
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fn check_for_uniq(cx: ctx, id: node_id, fv: Option<@freevar_entry>,
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is_move: bool, var_t: ty::t, sp: span) {
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// all captured data must be sendable, regardless of whether it is
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// moved in or copied in. Note that send implies owned.
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if !check_send(cx, var_t, sp) { return; }
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// copied in data must be copyable, but moved in data can be anything
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let is_implicit = fv.is_some();
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if !is_move {
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check_copy(cx, id, var_t, sp, is_implicit,
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Some(("non-copyable value cannot be copied into a \
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~fn closure",
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"to copy values into a ~fn closure, use a \
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capture clause: `fn~(copy x)` or `|copy x|`")));
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}
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// check that only immutable variables are implicitly copied in
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for fv.each |fv| {
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check_imm_free_var(cx, fv.def, fv.span);
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}
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}
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fn check_for_box(cx: ctx, id: node_id, fv: Option<@freevar_entry>,
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is_move: bool, var_t: ty::t, sp: span) {
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// all captured data must be owned
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if !check_durable(cx.tcx, var_t, sp) { return; }
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// copied in data must be copyable, but moved in data can be anything
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let is_implicit = fv.is_some();
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if !is_move {
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check_copy(cx, id, var_t, sp, is_implicit,
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Some(("non-copyable value cannot be copied into a \
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@fn closure",
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"to copy values into a @fn closure, use a \
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capture clause: `fn~(copy x)` or `|copy x|`")));
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}
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// check that only immutable variables are implicitly copied in
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for fv.each |fv| {
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check_imm_free_var(cx, fv.def, fv.span);
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}
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}
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fn check_for_block(cx: ctx, _id: node_id, fv: Option<@freevar_entry>,
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_is_move: bool, _var_t: ty::t, sp: span) {
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// only restriction: no capture clauses (we would have to take
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// ownership of the moved/copied in data).
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if fv.is_none() {
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cx.tcx.sess.span_err(
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sp,
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~"cannot capture values explicitly with a block closure");
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}
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}
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fn check_for_bare(cx: ctx, _id: node_id, _fv: Option<@freevar_entry>,
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_is_move: bool, _var_t: ty::t, sp: span) {
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cx.tcx.sess.span_err(sp, ~"attempted dynamic environment capture");
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}
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let fty = ty::node_id_to_type(cx.tcx, id);
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match ty::ty_fn_proto(fty) {
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ProtoUniq => b(check_for_uniq),
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ProtoBox => b(check_for_box),
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ProtoBare => b(check_for_bare),
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ProtoBorrowed => b(check_for_block),
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}
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}
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// Check that the free variables used in a shared/sendable closure conform
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// to the copy/move kind bounds. Then recursively check the function body.
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fn check_fn(fk: visit::fn_kind, decl: fn_decl, body: blk, sp: span,
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fn_id: node_id, cx: ctx, v: visit::vt<ctx>) {
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// Find the check function that enforces the appropriate bounds for this
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// kind of function:
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do with_appropriate_checker(cx, fn_id) |chk| {
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// Begin by checking the variables in the capture clause, if any.
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// Here we slightly abuse the map function to both check and report
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// errors and produce a list of the def id's for all capture
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// variables. This list is used below to avoid checking and reporting
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// on a given variable twice.
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let cap_clause = match fk {
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visit::fk_anon(_, cc) | visit::fk_fn_block(cc) => cc,
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visit::fk_item_fn(*) | visit::fk_method(*) |
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visit::fk_dtor(*) => @~[]
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};
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let captured_vars = do (*cap_clause).map |cap_item| {
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let cap_def = cx.tcx.def_map.get(cap_item.id);
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let cap_def_id = ast_util::def_id_of_def(cap_def).node;
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let ty = ty::node_id_to_type(cx.tcx, cap_def_id);
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chk(cx, fn_id, None, cap_item.is_move, ty, cap_item.span);
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cap_def_id
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};
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// Iterate over any free variables that may not have appeared in the
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// capture list. Ensure that they too are of the appropriate kind.
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for vec::each(*freevars::get_freevars(cx.tcx, fn_id)) |fv| {
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let id = ast_util::def_id_of_def(fv.def).node;
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// skip over free variables that appear in the cap clause
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if captured_vars.contains(&id) { loop; }
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let ty = ty::node_id_to_type(cx.tcx, id);
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// is_move is true if this type implicitly moves and false
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// otherwise.
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let is_move = ty::type_implicitly_moves(cx.tcx, ty);
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chk(cx, fn_id, Some(*fv), is_move, ty, fv.span);
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}
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}
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visit::visit_fn(fk, decl, body, sp, fn_id, cx, v);
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}
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fn check_block(b: blk, cx: ctx, v: visit::vt<ctx>) {
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match b.node.expr {
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Some(ex) => maybe_copy(cx, ex,
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Some(("Tail expressions in blocks must be copyable",
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try_adding))),
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_ => ()
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}
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visit::visit_block(b, cx, v);
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}
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fn check_arm(a: arm, cx: ctx, v: visit::vt<ctx>) {
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for vec::each(a.pats) |p| {
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do pat_util::pat_bindings(cx.tcx.def_map, *p) |mode, id, span, _pth| {
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if mode == bind_by_value {
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let t = ty::node_id_to_type(cx.tcx, id);
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let reason = "consider binding with `ref` or `move` instead";
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check_copy(cx, id, t, span, false, Some((reason,reason)));
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}
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}
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}
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visit::visit_arm(a, cx, v);
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}
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fn check_expr(e: @expr, cx: ctx, v: visit::vt<ctx>) {
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debug!("kind::check_expr(%s)", expr_to_str(e, cx.tcx.sess.intr()));
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let id_to_use = match e.node {
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expr_index(*)|expr_assign_op(*)|
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expr_unary(*)|expr_binary(*)|expr_method_call(*) => e.callee_id,
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_ => e.id
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};
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// Handle any kind bounds on type parameters
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do option::iter(&cx.tcx.node_type_substs.find(id_to_use)) |ts| {
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let bounds = match e.node {
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expr_path(_) => {
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let did = ast_util::def_id_of_def(cx.tcx.def_map.get(e.id));
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ty::lookup_item_type(cx.tcx, did).bounds
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}
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_ => {
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// Type substitutions should only occur on paths and
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// method calls, so this needs to be a method call.
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// Even though the callee_id may have been the id with
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// node_type_substs, e.id is correct here.
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ty::method_call_bounds(cx.tcx, cx.method_map, e.id).expect(
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~"non path/method call expr has type substs??")
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}
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};
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if vec::len(*ts) != vec::len(*bounds) {
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// Fail earlier to make debugging easier
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fail fmt!("internal error: in kind::check_expr, length \
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mismatch between actual and declared bounds: actual = \
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%s (%u tys), declared = %? (%u tys)",
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tys_to_str(cx.tcx, *ts), ts.len(),
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*bounds, (*bounds).len());
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}
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for vec::each2(*ts, *bounds) |ty, bound| {
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check_bounds(cx, id_to_use, e.span, *ty, *bound)
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}
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}
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match /*bad*/copy e.node {
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expr_assign(_, ex) |
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expr_unary(box(_), ex) | expr_unary(uniq(_), ex) |
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expr_ret(Some(ex)) => {
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maybe_copy(cx, ex, Some(("returned values must be copyable",
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try_adding)));
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}
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expr_cast(source, _) => {
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maybe_copy(cx, source, Some(("casted values must be copyable",
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try_adding)));
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check_cast_for_escaping_regions(cx, source, e);
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check_kind_bounds_of_cast(cx, source, e);
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}
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expr_copy(expr) => check_copy_ex(cx, expr, false,
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Some(("explicit copy requires a copyable argument", ""))),
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// Vector add copies, but not "implicitly"
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expr_assign_op(_, _, ex) => check_copy_ex(cx, ex, false,
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Some(("assignment with operation requires \
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a copyable argument", ""))),
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expr_binary(add, ls, rs) => {
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let reason = Some(("binary operators require copyable arguments",
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""));
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check_copy_ex(cx, ls, false, reason);
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check_copy_ex(cx, rs, false, reason);
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}
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expr_rec(ref fields, def) | expr_struct(_, ref fields, def) => {
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for (*fields).each |field| { maybe_copy(cx, field.node.expr,
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Some(("record or struct fields require \
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copyable arguments", ""))); }
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match def {
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Some(ex) => {
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// All noncopyable fields must be overridden
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let t = ty::expr_ty(cx.tcx, ex);
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let ty_fields = match /*bad*/copy ty::get(t).sty {
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ty::ty_rec(f) => f,
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ty::ty_struct(did, ref substs) =>
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ty::struct_fields(cx.tcx, did, &(*substs)),
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_ => cx.tcx.sess.span_bug(ex.span,
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~"bad base expr type in record")
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};
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for ty_fields.each |tf| {
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if !vec::any((*fields), |f| f.node.ident == tf.ident ) &&
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!ty::kind_can_be_copied(ty::type_kind(cx.tcx, tf.mt.ty)) {
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cx.tcx.sess.span_err(e.span,
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~"copying a noncopyable value");
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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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expr_tup(exprs) | expr_vec(exprs, _) => {
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for exprs.each |expr| { maybe_copy(cx, *expr,
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Some(("tuple or vec elements must be copyable", ""))); }
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}
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expr_call(f, args, _) => {
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for ty::ty_fn_args(ty::expr_ty(cx.tcx, f)).eachi |i, arg_t| {
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match ty::arg_mode(cx.tcx, *arg_t) {
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by_copy => maybe_copy(cx, args[i],
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Some(("function arguments must be copyable",
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"try changing the function to take a reference \
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instead"))),
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by_ref | by_val | by_move => ()
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}
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}
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}
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expr_method_call(_, _, _, args, _) => {
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for ty::ty_fn_args(ty::node_id_to_type(cx.tcx, e.callee_id)).eachi
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|i, arg_t| {
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match ty::arg_mode(cx.tcx, *arg_t) {
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by_copy => maybe_copy(cx, args[i],
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Some(("function arguments must be copyable",
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"try changing the function to take a \
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reference instead"))),
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by_ref | by_val | by_move => ()
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}
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}
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}
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expr_field(lhs, _, _) => {
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// If this is a method call with a by-val argument, we need
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// to check the copy
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match cx.method_map.find(e.id) {
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Some(ref mme) => {
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match ty::arg_mode(cx.tcx, mme.self_arg) {
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by_copy => maybe_copy(cx, lhs,
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Some(("method call takes its self argument by copy",
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""))),
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by_ref | by_val | by_move => ()
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}
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}
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_ => ()
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}
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}
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expr_repeat(element, count_expr, _) => {
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let count = ty::eval_repeat_count(cx.tcx, count_expr, e.span);
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if count == 1 {
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maybe_copy(cx, element, Some(("trivial repeat takes its element \
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by copy", "")));
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} else {
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let element_ty = ty::expr_ty(cx.tcx, element);
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check_copy(cx, element.id, element_ty, element.span, true,
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Some(("repeat takes its elements by copy", "")));
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}
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}
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_ => { }
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}
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visit::visit_expr(e, cx, v);
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}
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fn check_stmt(stmt: @stmt, cx: ctx, v: visit::vt<ctx>) {
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match stmt.node {
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stmt_decl(@spanned {node: decl_local(ref locals), _}, _) => {
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for locals.each |local| {
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match local.node.init {
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Some(expr) =>
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maybe_copy(cx, expr, Some(("initializer statement \
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takes its right-hand side by copy", ""))),
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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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visit::visit_stmt(stmt, cx, v);
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}
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fn check_ty(aty: @Ty, cx: ctx, v: visit::vt<ctx>) {
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match aty.node {
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ty_path(_, id) => {
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do option::iter(&cx.tcx.node_type_substs.find(id)) |ts| {
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let did = ast_util::def_id_of_def(cx.tcx.def_map.get(id));
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let bounds = ty::lookup_item_type(cx.tcx, did).bounds;
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for vec::each2(*ts, *bounds) |ty, bound| {
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check_bounds(cx, aty.id, aty.span, *ty, *bound)
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}
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}
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}
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_ => {}
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}
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visit::visit_ty(aty, cx, v);
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}
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fn check_bounds(cx: ctx, id: node_id, sp: span,
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ty: ty::t, bounds: ty::param_bounds) {
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let kind = ty::type_kind(cx.tcx, ty);
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let p_kind = ty::param_bounds_to_kind(bounds);
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if !ty::kind_lteq(p_kind, kind) {
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// If the only reason the kind check fails is because the
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// argument type isn't implicitly copyable, consult the warning
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|
// settings to figure out what to do.
|
|
let implicit = ty::kind_implicitly_copyable() - ty::kind_copyable();
|
|
if ty::kind_lteq(p_kind, kind | implicit) {
|
|
cx.tcx.sess.span_lint(
|
|
non_implicitly_copyable_typarams,
|
|
id, cx.current_item, sp,
|
|
~"instantiating copy type parameter with a \
|
|
not implicitly copyable type");
|
|
} else {
|
|
cx.tcx.sess.span_err(
|
|
sp,
|
|
~"instantiating a type parameter with an incompatible type " +
|
|
~"(needs `" + kind_to_str(p_kind) +
|
|
~"`, got `" + kind_to_str(kind) +
|
|
~"`, missing `" + kind_to_str(p_kind - kind) + ~"`)");
|
|
}
|
|
}
|
|
}
|
|
|
|
fn maybe_copy(cx: ctx, ex: @expr, why: Option<(&str,&str)>) {
|
|
check_copy_ex(cx, ex, true, why);
|
|
}
|
|
|
|
fn is_nullary_variant(cx: ctx, ex: @expr) -> bool {
|
|
match ex.node {
|
|
expr_path(_) => {
|
|
match cx.tcx.def_map.get(ex.id) {
|
|
def_variant(edid, vdid) => {
|
|
vec::len(ty::enum_variant_with_id(cx.tcx, edid, vdid).args) == 0u
|
|
}
|
|
_ => false
|
|
}
|
|
}
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
fn check_copy_ex(cx: ctx, ex: @expr, implicit_copy: bool,
|
|
why: Option<(&str,&str)>) {
|
|
if ty::expr_is_lval(cx.tcx, cx.method_map, ex) &&
|
|
|
|
// a reference to a constant like `none`... no need to warn
|
|
// about *this* even if the type is Option<~int>
|
|
!is_nullary_variant(cx, ex) &&
|
|
|
|
// borrowed unique value isn't really a copy
|
|
!is_autorefd(cx, ex)
|
|
{
|
|
match cx.tcx.value_modes.find(ex.id) {
|
|
None => cx.tcx.sess.span_bug(ex.span, ~"no value mode for lval"),
|
|
Some(MoveValue) | Some(ReadValue) => {} // Won't be a copy.
|
|
Some(CopyValue) => {
|
|
debug!("(kind checking) is a copy value: `%s`",
|
|
expr_to_str(ex, cx.tcx.sess.intr()));
|
|
let ty = ty::expr_ty(cx.tcx, ex);
|
|
check_copy(cx, ex.id, ty, ex.span, implicit_copy, why);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn is_autorefd(cx: ctx, ex: @expr) -> bool {
|
|
match cx.tcx.adjustments.find(ex.id) {
|
|
None => false,
|
|
Some(ref adj) => adj.autoref.is_some()
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_imm_free_var(cx: ctx, def: def, sp: span) {
|
|
let msg = ~"mutable variables cannot be implicitly captured; \
|
|
use a capture clause";
|
|
match def {
|
|
def_local(_, is_mutbl) => {
|
|
if is_mutbl {
|
|
cx.tcx.sess.span_err(sp, msg);
|
|
}
|
|
}
|
|
def_arg(*) => { /* ok */ }
|
|
def_upvar(_, def1, _, _) => {
|
|
check_imm_free_var(cx, *def1, sp);
|
|
}
|
|
def_binding(*) | def_self(*) => { /*ok*/ }
|
|
_ => {
|
|
cx.tcx.sess.span_bug(
|
|
sp,
|
|
fmt!("unknown def for free variable: %?", def));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn check_copy(cx: ctx, id: node_id, ty: ty::t, sp: span,
|
|
implicit_copy: bool, why: Option<(&str,&str)>) {
|
|
let k = ty::type_kind(cx.tcx, ty);
|
|
if !ty::kind_can_be_copied(k) {
|
|
cx.tcx.sess.span_err(sp, ~"copying a noncopyable value");
|
|
do why.map |reason| {
|
|
cx.tcx.sess.span_note(sp, fmt!("%s", reason.first()));
|
|
};
|
|
} else if implicit_copy && !ty::kind_can_be_implicitly_copied(k) {
|
|
cx.tcx.sess.span_lint(
|
|
implicit_copies, id, cx.current_item,
|
|
sp,
|
|
~"implicitly copying a non-implicitly-copyable value");
|
|
do why.map |reason| {
|
|
cx.tcx.sess.span_note(sp, fmt!("%s", reason.second()));
|
|
};
|
|
}
|
|
}
|
|
|
|
fn check_send(cx: ctx, ty: ty::t, sp: span) -> bool {
|
|
if !ty::kind_can_be_sent(ty::type_kind(cx.tcx, ty)) {
|
|
cx.tcx.sess.span_err(sp, ~"not a sendable value");
|
|
false
|
|
} else {
|
|
true
|
|
}
|
|
}
|
|
|
|
// note: also used from middle::typeck::regionck!
|
|
fn check_durable(tcx: ty::ctxt, ty: ty::t, sp: span) -> bool {
|
|
if !ty::kind_is_durable(ty::type_kind(tcx, ty)) {
|
|
match ty::get(ty).sty {
|
|
ty::ty_param(*) => {
|
|
tcx.sess.span_err(sp, ~"value may contain borrowed \
|
|
pointers; use `&static` bound");
|
|
}
|
|
_ => {
|
|
tcx.sess.span_err(sp, ~"value may contain borrowed \
|
|
pointers");
|
|
}
|
|
}
|
|
false
|
|
} else {
|
|
true
|
|
}
|
|
}
|
|
|
|
/// This is rather subtle. When we are casting a value to a
|
|
/// instantiated trait like `a as trait/&r`, regionck already ensures
|
|
/// that any borrowed pointers that appear in the type of `a` are
|
|
/// bounded by `&r`. However, it is possible that there are *type
|
|
/// parameters* in the type of `a`, and those *type parameters* may
|
|
/// have borrowed pointers within them. We have to guarantee that the
|
|
/// regions which appear in those type parameters are not obscured.
|
|
///
|
|
/// Therefore, we ensure that one of three conditions holds:
|
|
///
|
|
/// (1) The trait instance cannot escape the current fn. This is
|
|
/// guaranteed if the region bound `&r` is some scope within the fn
|
|
/// itself. This case is safe because whatever borrowed pointers are
|
|
/// found within the type parameter, they must enclose the fn body
|
|
/// itself.
|
|
///
|
|
/// (2) The type parameter appears in the type of the trait. For
|
|
/// example, if the type parameter is `T` and the trait type is
|
|
/// `deque<T>`, then whatever borrowed ptrs may appear in `T` also
|
|
/// appear in `deque<T>`.
|
|
///
|
|
/// (3) The type parameter is owned (and therefore does not contain
|
|
/// borrowed ptrs).
|
|
fn check_cast_for_escaping_regions(
|
|
cx: ctx,
|
|
source: @expr,
|
|
target: @expr) {
|
|
|
|
// Determine what type we are casting to; if it is not an trait, then no
|
|
// worries.
|
|
let target_ty = ty::expr_ty(cx.tcx, target);
|
|
let target_substs = match ty::get(target_ty).sty {
|
|
ty::ty_trait(_, ref substs, _) => {(/*bad*/copy *substs)}
|
|
_ => { return; /* not a cast to a trait */ }
|
|
};
|
|
|
|
// Check, based on the region associated with the trait, whether it can
|
|
// possibly escape the enclosing fn item (note that all type parameters
|
|
// must have been declared on the enclosing fn item):
|
|
match target_substs.self_r {
|
|
Some(ty::re_scope(*)) => { return; /* case (1) */ }
|
|
None | Some(ty::re_static) | Some(ty::re_free(*)) => {}
|
|
Some(ty::re_bound(*)) | Some(ty::re_infer(*)) => {
|
|
cx.tcx.sess.span_bug(
|
|
source.span,
|
|
fmt!("bad region found in kind: %?", target_substs.self_r));
|
|
}
|
|
}
|
|
|
|
// Assuming the trait instance can escape, then ensure that each parameter
|
|
// either appears in the trait type or is owned:
|
|
let target_params = ty::param_tys_in_type(target_ty);
|
|
let source_ty = ty::expr_ty(cx.tcx, source);
|
|
do ty::walk_ty(source_ty) |ty| {
|
|
match ty::get(ty).sty {
|
|
ty::ty_param(source_param) => {
|
|
if target_params.contains(&source_param) {
|
|
/* case (2) */
|
|
} else {
|
|
check_durable(cx.tcx, ty, source.span); /* case (3) */
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Ensures that values placed into a ~Trait are copyable and sendable.
|
|
fn check_kind_bounds_of_cast(cx: ctx, source: @expr, target: @expr) {
|
|
let target_ty = ty::expr_ty(cx.tcx, target);
|
|
match ty::get(target_ty).sty {
|
|
ty::ty_trait(_, _, ty::vstore_uniq) => {
|
|
let source_ty = ty::expr_ty(cx.tcx, source);
|
|
let source_kind = ty::type_kind(cx.tcx, source_ty);
|
|
if !ty::kind_can_be_copied(source_kind) {
|
|
cx.tcx.sess.span_err(target.span,
|
|
~"uniquely-owned trait objects must be copyable");
|
|
}
|
|
if !ty::kind_can_be_sent(source_kind) {
|
|
cx.tcx.sess.span_err(target.span,
|
|
~"uniquely-owned trait objects must be sendable");
|
|
}
|
|
}
|
|
_ => {} // Nothing to do.
|
|
}
|
|
}
|
|
|
|
//
|
|
// Local Variables:
|
|
// mode: rust
|
|
// fill-column: 78;
|
|
// indent-tabs-mode: nil
|
|
// c-basic-offset: 4
|
|
// buffer-file-coding-system: utf-8-unix
|
|
// End:
|
|
//
|