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Don't ever raise unique kinds of pinned kinds to shared (again)

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So *resource, ~resource, [resource] are all pinned. This is counter to the
design of the kind system, but this way is a much clearer path to type safety.
Once we've established a good baseline with lots of tests, then we can try to
make raising pinned kinds work.
This commit is contained in:
Brian Anderson 2011-09-27 14:50:55 -07:00
parent e50580aa66
commit b8bb663df7
9 changed files with 25 additions and 37 deletions
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25
src/comp/middle/kind.rs
View file

@ -142,22 +142,6 @@ fn need_shared_lhs_rhs(tcx: ty::ctxt, a: @ast::expr, b: @ast::expr, op: str) {
need_expr_kind(tcx, b, ast::kind_shared, op + " rhs");
}
// Additional checks for copyability that require a little more nuance
fn check_copy(tcx: ty::ctxt, e: @ast::expr) {
alt ty::struct(tcx, ty::expr_ty(tcx, e)) {
// Unique boxes most not contain pinned kinds
ty::ty_uniq(mt) {
demand_kind(tcx, e.span, mt.ty, ast::kind_shared,
"unique box interior");
}
ty::ty_vec(mt) {
demand_kind(tcx, e.span, mt.ty, ast::kind_shared,
"vector interior");
}
_ { }
}
}
fn check_expr(tcx: ty::ctxt, e: @ast::expr) {
alt e.node {
@ -168,16 +152,13 @@ fn check_expr(tcx: ty::ctxt, e: @ast::expr) {
ast::expr_move(a, b) { need_shared_lhs_rhs(tcx, a, b, "<-"); }
ast::expr_assign(a, b) {
need_shared_lhs_rhs(tcx, a, b, "=");
check_copy(tcx, b);
}
ast::expr_assign_op(_, a, b) {
need_shared_lhs_rhs(tcx, a, b, "op=");
check_copy(tcx, b);
}
ast::expr_swap(a, b) { need_shared_lhs_rhs(tcx, a, b, "<->"); }
ast::expr_copy(a) {
need_expr_kind(tcx, a, ast::kind_shared, "'copy' operand");
check_copy(tcx, a);
}
ast::expr_ret(option::some(a)) {
need_expr_kind(tcx, a, ast::kind_shared, "'ret' operand");
@ -221,9 +202,11 @@ fn check_stmt(tcx: ty::ctxt, stmt: @ast::stmt) {
need_expr_kind(tcx, expr,
ast::kind_shared,
"local initializer");
check_copy(tcx, expr);
}
_ { /* fall through */ }
option::some({op: ast::init_move., expr}) {
// FIXME: Same as above
}
option::none. { /* fall through */ }
}
}
}

9
src/comp/middle/ty.rs
View file

@ -1022,7 +1022,14 @@ fn type_kind(cx: ctxt, ty: t) -> ast::kind {
// Pointers and unique containers raise pinned to shared.
ty_ptr(tm) | ty_vec(tm) | ty_uniq(tm) {
let k = type_kind(cx, tm.ty);
if k == ast::kind_pinned { k = ast::kind_shared; }
// FIXME (984) Doing this implies a lot of subtle rules about what can
// and can't be copied, so I'm going to start by not raising unique of
// pinned to shared, make sure that's relatively safe, then we can try
// to make this work.
// if k == ast::kind_pinned { k = ast::kind_shared; }
result = kind::lower_kind(result, k);
}
// Records lower to the lowest of their members.