--- /dev/null
+import syntax::{ast, ast_util, ast_map};
+import ast_util::path_to_ident;
+import ast::{ident, fn_ident, node_id};
+import syntax::codemap::span;
+import syntax::visit;
+import visit::vt;
+import std::list;
+import std::map::hashmap;
+import core::unreachable;
+import option::is_none;
+import list::list;
+import driver::session::session;
+import pat_util::*;
+import util::ppaux::ty_to_str;
+
+// This is not an alias-analyser (though it would merit from becoming one, or
+// getting input from one, to be more precise). It is a pass that checks
+// whether aliases are used in a safe way.
+
+enum copied { not_allowed, copied, not_copied, }
+enum invalid_reason { overwritten, val_taken, }
+type invalid = {reason: invalid_reason,
+ node_id: node_id,
+ sp: span, path: @ast::path};
+
+enum unsafe_ty { contains(ty::t), mutbl_contains(ty::t), }
+
+type binding = @{node_id: node_id,
+ span: span,
+ root_var: option<node_id>,
+ local_id: uint,
+ unsafe_tys: [unsafe_ty],
+ mut copied: copied};
+
+// FIXME it may be worthwhile to use a linked list of bindings instead
+type scope = {bs: [binding],
+ invalid: @mut @list<@invalid>};
+
+fn mk_binding(cx: ctx, id: node_id, span: span, root_var: option<node_id>,
+ unsafe_tys: [unsafe_ty]) -> binding {
+ alt root_var {
+ some(r_id) { cx.ref_map.insert(id, r_id); }
+ _ {}
+ }
+ ret @{node_id: id, span: span, root_var: root_var,
+ local_id: local_id_of_node(cx, id),
+ unsafe_tys: unsafe_tys,
+ mut copied: not_copied};
+}
+
+enum local_info { local(uint), }
+
+type copy_map = std::map::hashmap<node_id, ()>;
+type ref_map = std::map::hashmap<node_id, node_id>;
+
+type ctx = {tcx: ty::ctxt,
+ copy_map: copy_map,
+ ref_map: ref_map,
+ mut silent: bool};
+
+fn check_crate(tcx: ty::ctxt, crate: @ast::crate) -> (copy_map, ref_map) {
+ // Stores information about function arguments that's otherwise not easily
+ // available.
+ let cx = @{tcx: tcx,
+ copy_map: std::map::int_hash(),
+ ref_map: std::map::int_hash(),
+ mut silent: false};
+ let v = @{visit_fn: bind visit_fn(cx, _, _, _, _, _, _, _),
+ visit_expr: bind visit_expr(cx, _, _, _),
+ visit_block: bind visit_block(cx, _, _, _)
+ with *visit::default_visitor::<scope>()};
+ let sc = {bs: [], invalid: @mut @list::nil};
+ visit::visit_crate(*crate, sc, visit::mk_vt(v));
+ tcx.sess.abort_if_errors();
+ ret (cx.copy_map, cx.ref_map);
+}
+
+fn visit_fn(cx: @ctx, _fk: visit::fn_kind, decl: ast::fn_decl,
+ body: ast::blk, _sp: span,
+ id: ast::node_id, sc: scope, v: vt<scope>) {
+ visit::visit_fn_decl(decl, sc, v);
+ let fty = ty::node_id_to_type(cx.tcx, id);
+
+ // Blocks need to obey any restrictions from the enclosing scope, and may
+ // be called multiple times.
+ let proto = ty::ty_fn_proto(fty);
+ alt proto {
+ ast::proto_block | ast::proto_any {
+ check_loop(*cx, sc) {|| v.visit_block(body, sc, v);}
+ }
+ ast::proto_box | ast::proto_uniq | ast::proto_bare {
+ let sc = {bs: [], invalid: @mut @list::nil};
+ v.visit_block(body, sc, v);
+ }
+ }
+}
+
+fn visit_expr(cx: @ctx, ex: @ast::expr, sc: scope, v: vt<scope>) {
+ let mut handled = true;
+ alt ex.node {
+ ast::expr_call(f, args, _) {
+ check_call(cx, sc, f, args, v);
+ visit_expr(cx, f, sc, v);
+ }
+ ast::expr_alt(input, arms, _) { check_alt(*cx, input, arms, sc, v); }
+ ast::expr_path(pt) {
+ check_var(*cx, ex, pt, ex.id, false, sc);
+ handled = false;
+ }
+ ast::expr_swap(lhs, rhs) {
+ check_lval(cx, lhs, sc, v);
+ check_lval(cx, rhs, sc, v);
+ handled = false;
+ }
+ ast::expr_move(dest, src) {
+ visit_expr(cx, src, sc, v);
+ check_lval(cx, dest, sc, v);
+ check_lval(cx, src, sc, v);
+ }
+ ast::expr_assign(dest, src) | ast::expr_assign_op(_, dest, src) {
+ visit_expr(cx, src, sc, v);
+ check_lval(cx, dest, sc, v);
+ }
+ ast::expr_if(c, then, els) { check_if(c, then, els, sc, v); }
+ ast::expr_while(_, _) {
+ check_loop(*cx, sc) {|| visit::visit_expr(ex, sc, v); }
+ }
+ _ { handled = false; }
+ }
+ if !handled { visit::visit_expr(ex, sc, v); }
+}
+
+fn visit_block(cx: @ctx, b: ast::blk, sc: scope, v: vt<scope>) {
+ let sc = sc;
+ for b.node.stmts.each {|stmt|
+ alt stmt.node {
+ ast::stmt_decl(@{node: ast::decl_item(it), _}, _) {
+ v.visit_item(it, sc, v);
+ }
+ ast::stmt_decl(@{node: ast::decl_local(locs), _}, _) {
+ for locs.each {|loc|
+ alt loc.node.init {
+ some(init) {
+ if init.op == ast::init_move {
+ check_lval(cx, init.expr, sc, v);
+ } else {
+ visit_expr(cx, init.expr, sc, v);
+ }
+ }
+ none { }
+ }
+ }
+ }
+ ast::stmt_expr(ex, _) | ast::stmt_semi(ex, _) {
+ v.visit_expr(ex, sc, v);
+ }
+ }
+ }
+ visit::visit_expr_opt(b.node.expr, sc, v);
+}
+
+fn cant_copy(cx: ctx, b: binding) -> bool {
+
+ if cx.tcx.sess.opts.borrowck == 2u {
+ // borrowck is enabled. disable alias analysis.
+ ret false;
+ }
+
+ alt b.copied {
+ not_allowed { ret true; }
+ copied { ret false; }
+ not_copied {}
+ }
+ let ty = ty::node_id_to_type(cx.tcx, b.node_id);
+ if ty::type_allows_implicit_copy(cx.tcx, ty) {
+ b.copied = copied;
+ cx.copy_map.insert(b.node_id, ());
+ if copy_is_expensive(cx.tcx, ty) {
+ cx.tcx.sess.span_warn(b.span,
+ "inserting an implicit copy for type " +
+ util::ppaux::ty_to_str(cx.tcx, ty));
+ }
+ ret false;
+ } else { ret true; }
+}
+
+// FIXME this is a really awful hack
+fn local_id_for_args(cx: ctx, args: [@ast::expr]) -> uint {
+ for vec::each(args) {|arg|
+ alt arg.node {
+ ast::expr_fn_block(decl, _, _) | ast::expr_fn(_, decl, _, _) |
+ ast::expr_loop_body(@{node: ast::expr_fn_block(decl, _, _), _}) {
+ if decl.inputs.len() > 0u {
+ ret local_id_of_node(cx, decl.inputs[0].id);
+ }
+ }
+ _ {}
+ }
+ }
+ 0xFFFFFFFFu
+}
+
+fn check_call(cx: @ctx, sc: scope, f: @ast::expr, args: [@ast::expr],
+ v: vt<scope>) {
+ let fty = ty::expr_ty(cx.tcx, f);
+ let arg_ts = ty::ty_fn_args(fty);
+ let mut mut_roots: [{arg: @ast::expr, node: node_id}] = [];
+ let mut bindings = [];
+ let mut blocks = [], loc_id = local_id_for_args(*cx, args);
+ vec::iter2(args, arg_ts) {|arg, arg_t|
+ let root = expr_root(*cx, arg, false);
+ alt ty::resolved_mode(cx.tcx, arg_t.mode) {
+ ast::by_mutbl_ref {
+ alt path_def(*cx, arg) {
+ some(def) {
+ let dnum = ast_util::def_id_of_def(def).node;
+ mut_roots += [{arg: arg, node: dnum}];
+ }
+ _ { }
+ }
+ }
+ ast::by_ref | ast::by_val | ast::by_move | ast::by_copy {}
+ }
+ alt arg.node {
+ ast::expr_fn_block(*) { blocks += [arg]; }
+ ast::expr_loop_body(b) { blocks += [b]; }
+ _ {
+ let root_var = path_def_id(*cx, root.ex);
+ let arg_copied = alt ty::resolved_mode(cx.tcx, arg_t.mode) {
+ ast::by_move | ast::by_copy { copied }
+ ast::by_mutbl_ref { not_allowed }
+ ast::by_ref | ast::by_val { not_copied }
+ };
+ visit_expr(cx, arg, sc, v);
+ bindings += [@{node_id: arg.id,
+ span: arg.span,
+ root_var: root_var,
+ local_id: loc_id,
+ unsafe_tys: unsafe_set(root.mutbl),
+ mut copied: arg_copied}];
+ }
+ }
+ }
+ let f_may_close = alt f.node {
+ ast::expr_path(_) { def_is_local_or_self(cx.tcx.def_map.get(f.id)) }
+ _ { true }
+ };
+ if f_may_close {
+ let mut i = 0u;
+ for bindings.each {|b|
+ let mut unsfe = vec::len(b.unsafe_tys) > 0u;
+ alt b.root_var {
+ some(rid) {
+ for sc.bs.each {|o|
+ if o.node_id == rid && vec::len(o.unsafe_tys) > 0u {
+ unsfe = true; break;
+ }
+ }
+ }
+ _ {}
+ }
+ if unsfe && cant_copy(*cx, b) {
+ err(*cx, f.span, #fmt["function may alias with argument \
+ %u, which is not immutably rooted", i]);
+ }
+ i += 1u;
+ }
+ }
+ let mut j = 0u;
+ for bindings.each {|b|
+ for b.unsafe_tys.each {|unsafe_ty|
+ vec::iteri(arg_ts) {|i, arg_t|
+ let mut_alias =
+ (ast::by_mutbl_ref == ty::arg_mode(cx.tcx, arg_t));
+ alt args[i].node {
+ ast::expr_fn_block(*) | ast::expr_loop_body(_) {}
+ _ {
+ if i != j && ty_can_unsafely_include(
+ *cx, unsafe_ty, arg_t.ty, mut_alias) &&
+ cant_copy(*cx, b) {
+ err(*cx, args[i].span,
+ #fmt["argument %u may alias with argument %u, \
+ which is not immutably rooted", i, j]);
+ }
+ }
+ }
+ }
+ }
+ j += 1u;
+ }
+
+ // Ensure we're not passing a root by mut alias.
+ for mut_roots.each {|mroot|
+ for bindings.each {|b|
+ if b.node_id != mroot.arg.id {
+ alt b.root_var {
+ some(root) {
+ if mroot.node == root && cant_copy(*cx, b) {
+ err(*cx, mroot.arg.span,
+ "passing a mut reference to a \
+ variable that roots another reference");
+ break;
+ }
+ }
+ none { }
+ }
+ }
+ }
+ }
+ // Check the bodies of block arguments against the current scope
+ if blocks.len() > 0u {
+ let inner_sc = {bs: bindings + sc.bs, invalid: sc.invalid};
+ for blocks.each {|blk|
+ alt check blk.node {
+ ast::expr_fn_block(_, body, _) {
+ v.visit_block(body, inner_sc, v);
+ }
+ }
+ }
+ for bindings.each {|binding|
+ test_scope(*cx, sc, binding, none);
+ }
+ }
+}
+
+#[warn(no_non_implicitly_copyable_typarams)]
+fn check_alt(cx: ctx, input: @ast::expr, arms: [ast::arm], sc: scope,
+ v: vt<scope>) {
+ v.visit_expr(input, sc, v);
+ let orig_invalid = *sc.invalid;
+ let mut all_invalid = orig_invalid;
+ let root = expr_root(cx, input, true);
+ for arms.each {|a|
+ let mut new_bs = sc.bs;
+ let root_var = path_def_id(cx, root.ex);
+ let pat_id_map = pat_util::pat_id_map(cx.tcx.def_map, a.pats[0]);
+ type info = {
+ id: node_id,
+ mut unsafe_tys: [unsafe_ty],
+ span: span};
+ let mut binding_info: [info] = [];
+ for a.pats.each {|pat|
+ for pattern_roots(cx.tcx, root.mutbl, pat).each {|proot|
+ let canon_id = pat_id_map.get(proot.name);
+ alt vec::find(binding_info, {|x| x.id == canon_id}) {
+ some(s) { s.unsafe_tys += unsafe_set(proot.mutbl); }
+ none {
+ binding_info += [
+ {id: canon_id,
+ mut unsafe_tys: unsafe_set(proot.mutbl),
+ span: proot.span}];
+ }
+ }
+ }
+ }
+ for binding_info.each {|info|
+ new_bs += [mk_binding(cx, info.id, info.span, root_var,
+ copy info.unsafe_tys)];
+ };
+ *sc.invalid = orig_invalid;
+ visit::visit_arm(a, {bs: new_bs with sc}, v);
+ all_invalid = join_invalid(all_invalid, *sc.invalid);
+ };
+ *sc.invalid = all_invalid;
+}
+
+fn check_for(cx: ctx, local: @ast::local, seq: @ast::expr, blk: ast::blk,
+ sc: scope, v: vt<scope>) {
+ let root = expr_root(cx, seq, false);
+
+ // If this is a mut vector, don't allow it to be touched.
+ let seq_t = ty::expr_ty(cx.tcx, seq);
+ let mut cur_mutbl = root.mutbl;
+ alt ty::get(seq_t).struct {
+ ty::ty_vec(mt) {
+ if mt.mutbl != ast::m_imm {
+ cur_mutbl = some(contains(seq_t));
+ }
+ }
+ _ {}
+ }
+ let root_var = path_def_id(cx, root.ex);
+ let mut new_bs = sc.bs;
+ for pattern_roots(cx.tcx, cur_mutbl, local.node.pat).each {|proot|
+ new_bs += [mk_binding(cx, proot.id, proot.span, root_var,
+ unsafe_set(proot.mutbl))];
+ }
+ visit::visit_block(blk, {bs: new_bs with sc}, v);
+}
+
+fn check_var(cx: ctx, ex: @ast::expr, p: @ast::path, id: ast::node_id,
+ assign: bool, sc: scope) {
+ let def = cx.tcx.def_map.get(id);
+ if !def_is_local_or_self(def) { ret; }
+ let my_defnum = ast_util::def_id_of_def(def).node;
+ let my_local_id = local_id_of_node(cx, my_defnum);
+ let var_t = ty::expr_ty(cx.tcx, ex);
+ for sc.bs.each {|b|
+ // excludes variables introduced since the alias was made
+ if my_local_id < b.local_id {
+ for b.unsafe_tys.each {|unsafe_ty|
+ if ty_can_unsafely_include(cx, unsafe_ty, var_t, assign) {
+ let inv = @{reason: val_taken, node_id: b.node_id,
+ sp: ex.span, path: p};
+ *sc.invalid = @list::cons(inv, *sc.invalid);
+ }
+ }
+ } else if b.node_id == my_defnum {
+ test_scope(cx, sc, b, some(p));
+ }
+ }
+}
+
+fn check_lval(cx: @ctx, dest: @ast::expr, sc: scope, v: vt<scope>) {
+ alt dest.node {
+ ast::expr_path(p) {
+ let def = cx.tcx.def_map.get(dest.id);
+ let dnum = ast_util::def_id_of_def(def).node;
+ for sc.bs.each {|b|
+ if b.root_var == some(dnum) {
+ let inv = @{reason: overwritten, node_id: b.node_id,
+ sp: dest.span, path: p};
+ *sc.invalid = @list::cons(inv, *sc.invalid);
+ }
+ }
+ }
+ _ { visit_expr(cx, dest, sc, v); }
+ }
+}
+
+fn check_if(c: @ast::expr, then: ast::blk, els: option<@ast::expr>,
+ sc: scope, v: vt<scope>) {
+ v.visit_expr(c, sc, v);
+ let orig_invalid = *sc.invalid;
+ v.visit_block(then, sc, v);
+ let then_invalid = *sc.invalid;
+ *sc.invalid = orig_invalid;
+ visit::visit_expr_opt(els, sc, v);
+ *sc.invalid = join_invalid(*sc.invalid, then_invalid);
+}
+
+fn check_loop(cx: ctx, sc: scope, checker: fn()) {
+ let orig_invalid = filter_invalid(*sc.invalid, sc.bs);
+ checker();
+ let new_invalid = filter_invalid(*sc.invalid, sc.bs);
+ // Have to check contents of loop again if it invalidated an alias
+ if list::len(orig_invalid) < list::len(new_invalid) {
+ let old_silent = cx.silent;
+ cx.silent = true;
+ checker();
+ cx.silent = old_silent;
+ }
+ *sc.invalid = new_invalid;
+}
+
+fn test_scope(cx: ctx, sc: scope, b: binding, p: option<@ast::path>) {
+ let mut prob = find_invalid(b.node_id, *sc.invalid);
+ alt b.root_var {
+ some(dn) {
+ for sc.bs.each {|other|
+ if !is_none(prob) { break; }
+ if other.node_id == dn {
+ prob = find_invalid(other.node_id, *sc.invalid);
+ }
+ }
+ }
+ _ {}
+ }
+ if !is_none(prob) && cant_copy(cx, b) {
+ let i = option::get(prob);
+ let msg = alt i.reason {
+ overwritten { "overwriting " + ast_util::path_name(i.path) }
+ val_taken { "taking the value of " + ast_util::path_name(i.path) }
+ };
+ let refname = alt p {
+ some(pt) { "reference " + ast_util::path_name(pt) +
+ ", which is still used" }
+ none { "an argument" }
+ };
+ err(cx, i.sp, msg + " will invalidate " + refname);
+ }
+}
+
+fn path_def(cx: ctx, ex: @ast::expr) -> option<ast::def> {
+ ret alt ex.node {
+ ast::expr_path(_) { some(cx.tcx.def_map.get(ex.id)) }
+ _ { none }
+ }
+}
+
+fn path_def_id(cx: ctx, ex: @ast::expr) -> option<ast::node_id> {
+ alt ex.node {
+ ast::expr_path(_) {
+ ret some(ast_util::def_id_of_def(cx.tcx.def_map.get(ex.id)).node);
+ }
+ _ { ret none; }
+ }
+}
+
+fn ty_can_unsafely_include(cx: ctx, needle: unsafe_ty, haystack: ty::t,
+ mutbl: bool) -> bool {
+ fn get_mutbl(cur: bool, mt: ty::mt) -> bool {
+ ret cur || mt.mutbl != ast::m_imm;
+ }
+ fn helper(tcx: ty::ctxt, needle: unsafe_ty, haystack: ty::t, mutbl: bool)
+ -> bool {
+ if alt needle {
+ contains(ty) { ty == haystack }
+ mutbl_contains(ty) { mutbl && ty == haystack }
+ } { ret true; }
+ alt ty::get(haystack).struct {
+ ty::ty_enum(_, ts) {
+ for ts.tps.each {|t|
+ if helper(tcx, needle, t, mutbl) { ret true; }
+ }
+ ret false;
+ }
+ ty::ty_box(mt) | ty::ty_ptr(mt) | ty::ty_uniq(mt) {
+ ret helper(tcx, needle, mt.ty, get_mutbl(mutbl, mt));
+ }
+ ty::ty_rec(fields) {
+ for fields.each {|f|
+ if helper(tcx, needle, f.mt.ty, get_mutbl(mutbl, f.mt)) {
+ ret true;
+ }
+ }
+ ret false;
+ }
+ ty::ty_tup(ts) {
+ for ts.each {|t| if helper(tcx, needle, t, mutbl) { ret true; } }
+ ret false;
+ }
+ ty::ty_fn({proto: ast::proto_bare, _}) { ret false; }
+ // These may contain anything.
+ ty::ty_fn(_) | ty::ty_iface(_, _) { ret true; }
+ // A type param may include everything, but can only be
+ // treated as opaque downstream, and is thus safe unless we
+ // saw mut fields, in which case the whole thing can be
+ // overwritten.
+ ty::ty_param(_, _) { ret mutbl; }
+ _ { ret false; }
+ }
+ }
+ ret helper(cx.tcx, needle, haystack, mutbl);
+}
+
+fn def_is_local_or_self(d: ast::def) -> bool {
+ alt d {
+ ast::def_local(_, _) | ast::def_arg(_, _) | ast::def_binding(_) |
+ ast::def_upvar(_, _, _) | ast::def_self(_) { true }
+ _ { false }
+ }
+}
+
+fn local_id_of_node(cx: ctx, id: node_id) -> uint {
+ alt cx.tcx.items.find(id) {
+ some(ast_map::node_arg(_, id)) | some(ast_map::node_local(id)) { id }
+ _ { 0u }
+ }
+}
+
+// Heuristic, somewhat random way to decide whether to warn when inserting an
+// implicit copy.
+fn copy_is_expensive(tcx: ty::ctxt, ty: ty::t) -> bool {
+ fn score_ty(tcx: ty::ctxt, ty: ty::t) -> uint {
+ ret alt ty::get(ty).struct {
+ ty::ty_nil | ty::ty_bot | ty::ty_bool | ty::ty_int(_) |
+ ty::ty_uint(_) | ty::ty_float(_) | ty::ty_type |
+ ty::ty_ptr(_) { 1u }
+ ty::ty_box(_) | ty::ty_iface(_, _) { 3u }
+ ty::ty_constr(t, _) | ty::ty_res(_, t, _) { score_ty(tcx, t) }
+ ty::ty_fn(_) { 4u }
+ ty::ty_str | ty::ty_vec(_) | ty::ty_param(_, _) { 50u }
+ ty::ty_uniq(mt) { 1u + score_ty(tcx, mt.ty) }
+ ty::ty_enum(_, substs) {
+ substs.tps.foldl(0u) { |sum, t| sum + score_ty(tcx, t) }
+ }
+ ty::ty_tup(ts) {
+ ts.foldl(0u) { |sum, t| sum + score_ty(tcx, t) }
+ }
+ ty::ty_rec(fs) {
+ let mut sum = 0u;
+ for fs.each {|f| sum += score_ty(tcx, f.mt.ty); }
+ sum
+ }
+ _ {
+ tcx.sess.warn(#fmt("score_ty: unexpected type %s",
+ ty_to_str(tcx, ty)));
+ 1u // ???
+ }
+ };
+ }
+ ret score_ty(tcx, ty) > 8u;
+}
+
+type pattern_root = {id: node_id,
+ name: ident,
+ mutbl: option<unsafe_ty>,
+ span: span};
+
+fn pattern_roots(tcx: ty::ctxt, mutbl: option<unsafe_ty>, pat: @ast::pat)
+ -> [pattern_root] {
+ fn walk(tcx: ty::ctxt, mutbl: option<unsafe_ty>, pat: @ast::pat,
+ &set: [pattern_root]) {
+ alt pat.node {
+ ast::pat_ident(nm, sub)
+ if !pat_util::pat_is_variant(tcx.def_map, pat) {
+ set += [{id: pat.id, name: path_to_ident(nm), mutbl: mutbl,
+ span: pat.span}];
+ option::iter(sub) {|p| walk(tcx, mutbl, p, set); };
+ }
+ ast::pat_wild | ast::pat_lit(_) | ast::pat_range(_, _) |
+ ast::pat_ident(_, _) | ast::pat_enum(_, none) {}
+ ast::pat_enum(_, some(ps)) | ast::pat_tup(ps) {
+ for ps.each {|p| walk(tcx, mutbl, p, set); }
+ }
+ ast::pat_rec(fs, _) {
+ let ty = ty::node_id_to_type(tcx, pat.id);
+ for fs.each {|f|
+ let m = ty::get_field(ty, f.ident).mt.mutbl != ast::m_imm,
+ c = if m { some(contains(ty)) } else { mutbl };
+ walk(tcx, c, f.pat, set);
+ }
+ }
+ ast::pat_box(p) {
+ let ty = ty::node_id_to_type(tcx, pat.id);
+ let m = alt ty::get(ty).struct {
+ ty::ty_box(mt) { mt.mutbl != ast::m_imm }
+ _ { tcx.sess.span_bug(pat.span, "box pat has non-box type"); }
+ },
+ c = if m {some(contains(ty)) } else { mutbl };
+ walk(tcx, c, p, set);
+ }
+ ast::pat_uniq(p) {
+ let ty = ty::node_id_to_type(tcx, pat.id);
+ let m = alt ty::get(ty).struct {
+ ty::ty_uniq(mt) { mt.mutbl != ast::m_imm }
+ _ { tcx.sess.span_bug(pat.span, "uniq pat has non-uniq type"); }
+ },
+ c = if m { some(contains(ty)) } else { mutbl };
+ walk(tcx, c, p, set);
+ }
+ }
+ }
+ let mut set = [];
+ walk(tcx, mutbl, pat, set);
+ ret set;
+}
+
+enum deref_t { unbox(bool), field, index, }
+
+type deref = @{mutbl: bool, kind: deref_t, outer_t: ty::t};
+
+fn expr_root(cx: ctx, ex: @ast::expr, autoderef: bool)
+ -> {ex: @ast::expr, mutbl: option<unsafe_ty>} {
+
+ fn maybe_auto_unbox(tcx: ty::ctxt, t: ty::t) -> {t: ty::t, ds: [deref]} {
+ let mut ds = [], t = t;
+ loop {
+ alt ty::get(t).struct {
+ ty::ty_box(mt) | ty::ty_uniq(mt) | ty::ty_rptr(_, mt) {
+ ds += [@{mutbl: mt.mutbl == ast::m_mutbl,
+ kind: unbox(false),
+ outer_t: t}];
+ t = mt.ty;
+ }
+ ty::ty_res(_, inner, substs) {
+ ds += [@{mutbl: false, kind: unbox(false), outer_t: t}];
+ t = ty::subst(tcx, substs, inner);
+ }
+ ty::ty_enum(did, substs) {
+ let variants = ty::enum_variants(tcx, did);
+ if vec::len(*variants) != 1u ||
+ vec::len(variants[0].args) != 1u {
+ break;
+ }
+ ds += [@{mutbl: false, kind: unbox(false), outer_t: t}];
+ t = ty::subst(tcx, substs, variants[0].args[0]);
+ }
+ _ { break; }
+ }
+ }
+ ret {t: t, ds: ds};
+ }
+
+ fn expr_root_(tcx: ty::ctxt, ctor_self: option<node_id>,
+ ex: @ast::expr, autoderef: bool) -> {ex: @ast::expr,
+ ds: @[deref]} {
+ let mut ds: [deref] = [], ex = ex;
+ loop {
+ alt copy ex.node {
+ ast::expr_field(base, ident, _) {
+ let auto_unbox =
+ maybe_auto_unbox(tcx, ty::expr_ty(tcx, base));
+ let mut is_mutbl = false;
+ alt ty::get(auto_unbox.t).struct {
+ ty::ty_rec(fields) {
+ for fields.each {|fld|
+ if str::eq(ident, fld.ident) {
+ is_mutbl = fld.mt.mutbl == ast::m_mutbl;
+ break;
+ }
+ }
+ }
+ ty::ty_class(did, _) {
+ util::common::log_expr(*base);
+ let in_self = alt ctor_self {
+ some(selfid) {
+ alt tcx.def_map.find(base.id) {
+ some(ast::def_self(slfid)) { slfid == selfid }
+ _ { false }
+ }
+ }
+ none { false }
+ };
+ for ty::lookup_class_fields(tcx, did).each {|fld|
+ if str::eq(ident, fld.ident) {
+ is_mutbl = fld.mutability == ast::class_mutable
+ || in_self; // all fields can be mutated
+ // in the ctor
+ break;
+ }
+ }
+ }
+ _ {}
+ }
+ ds += [@{mutbl:is_mutbl, kind:field, outer_t:auto_unbox.t}];
+ ds += auto_unbox.ds;
+ ex = base;
+ }
+ ast::expr_index(base, _) {
+ let auto_unbox =
+ maybe_auto_unbox(tcx, ty::expr_ty(tcx, base));
+ alt ty::get(auto_unbox.t).struct {
+ ty::ty_evec(mt, _) |
+ ty::ty_vec(mt) {
+ ds +=
+ [@{mutbl: mt.mutbl == ast::m_mutbl,
+ kind: index,
+ outer_t: auto_unbox.t}];
+ }
+ ty::ty_estr(_) |
+ ty::ty_str {
+ ds += [@{mutbl:false, kind:index, outer_t:auto_unbox.t}];
+ }
+ _ { break; }
+ }
+ ds += auto_unbox.ds;
+ ex = base;
+ }
+ ast::expr_unary(op, base) {
+ if op == ast::deref {
+ let base_t = ty::expr_ty(tcx, base);
+ let mut is_mutbl = false, ptr = false;
+ alt ty::get(base_t).struct {
+ ty::ty_box(mt) { is_mutbl = mt.mutbl==ast::m_mutbl; }
+ ty::ty_uniq(mt) { is_mutbl = mt.mutbl==ast::m_mutbl; }
+ ty::ty_res(_, _, _) { }
+ ty::ty_enum(_, _) { }
+ ty::ty_ptr(mt) | ty::ty_rptr(_, mt) {
+ is_mutbl = mt.mutbl==ast::m_mutbl;
+ ptr = true;
+ }
+ _ {
+ tcx.sess.span_bug(
+ base.span,
+ "ill-typed base expression in deref"); }
+ }
+ ds += [@{mutbl: is_mutbl, kind: unbox(ptr && is_mutbl),
+ outer_t: base_t}];
+ ex = base;
+ } else { break; }
+ }
+ _ { break; }
+ }
+ }
+ if autoderef {
+ let auto_unbox = maybe_auto_unbox(tcx, ty::expr_ty(tcx, ex));
+ ds += auto_unbox.ds;
+ }
+ ret {ex: ex, ds: @ds};
+ }
+
+ let base_root = expr_root_(cx.tcx, none, ex, autoderef);
+ let mut unsafe_ty = none;
+ for vec::each(*base_root.ds) {|d|
+ if d.mutbl { unsafe_ty = some(contains(d.outer_t)); break; }
+ }
+ ret {ex: base_root.ex, mutbl: unsafe_ty};
+}
+
+fn unsafe_set(from: option<unsafe_ty>) -> [unsafe_ty] {
+ alt from { some(t) { [t] } _ { [] } }
+}
+
+fn find_invalid(id: node_id, lst: @list<@invalid>) -> option<@invalid> {
+ let mut cur = lst;
+ loop {
+ alt *cur {
+ list::nil { ret none; }
+ list::cons(head, tail) {
+ if head.node_id == id { ret some(head); }
+ cur = tail;
+ }
+ }
+ };
+}
+
+fn join_invalid(a: @list<@invalid>, b: @list<@invalid>) -> @list<@invalid> {
+ let mut result = a;
+ list::iter(b) {|elt|
+ let mut found = false;
+ list::iter(a) {|e| if e == elt { found = true; } }
+ if !found { result = @list::cons(elt, result); }
+ }
+ result
+}
+
+fn filter_invalid(src: @list<@invalid>, bs: [binding]) -> @list<@invalid> {
+ let mut out = @list::nil, cur = src;
+ loop {
+ alt *cur {
+ list::cons(head, tail) {
+ let p = vec::position(bs, {|b| b.node_id == head.node_id});
+ if !is_none(p) { out = @list::cons(head, out); }
+ cur = tail;
+ }
+ list::nil {
+ ret out;
+ }
+ }
+ }
+}
+
+fn err(cx: ctx, sp: span, err: str) {
+ if !cx.silent || !cx.tcx.sess.has_errors() {
+ cx.tcx.sess.span_err(sp, err);
+ }
+}
+
+// Local Variables:
+// mode: rust
+// fill-column: 78;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// End:
projects / rust.git / commitdiff