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Extend region guarantor logic to handle autoref, which will 

be necessary for reborrowing.

r=catamorphism
This commit is contained in:
Niko Matsakis 2013-01-25 10:03:28 -08:00
parent 8f14d43206
commit a4ba11189d
1 changed files with 126 additions and 84 deletions
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210
src/librustc/middle/typeck/check/regionck.rs
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@ -73,10 +73,10 @@ fn encl_region_of_def(fcx: @fn_ctxt, def: ast::def) -> ty::Region {
}
impl @rcx {
fn resolve_type(unresolved_ty: ty::t) -> Option<ty::t> {
fn resolve_type(unresolved_ty: ty::t) -> ty::t {
/*!
* Try to resolve the type for the given node, returning
* None if an error results. Note that we never care
* t_err if an error results. Note that we never care
* about the details of the error, the same error will be
* detected and reported in the writeback phase.
*
@ -104,13 +104,13 @@ impl @rcx {
*/
match resolve_type(self.fcx.infcx(), unresolved_ty,
resolve_and_force_all_but_regions) {
Ok(t) => Some(t),
Err(_) => None
Ok(t) => t,
Err(_) => ty::mk_err(self.fcx.tcx())
}
}
/// Try to resolve the type for the given node.
fn resolve_node_type(id: ast::node_id) -> Option<ty::t> {
fn resolve_node_type(id: ast::node_id) -> ty::t {
self.resolve_type(self.fcx.node_ty(id))
}
}
@ -181,6 +181,12 @@ fn visit_block(b: ast::blk, &&rcx: @rcx, v: rvt) {
fn visit_expr(expr: @ast::expr, &&rcx: @rcx, v: rvt) {
debug!("visit_expr(e=%s)", rcx.fcx.expr_to_str(expr));
for rcx.fcx.inh.adjustments.find(expr.id).each |adjustment| {
for adjustment.autoref.each |autoref| {
guarantor::for_autoref(rcx, expr, *adjustment, autoref);
}
}
match /*bad*/copy expr.node {
ast::expr_path(*) => {
// Avoid checking the use of local variables, as we
@ -250,15 +256,14 @@ fn visit_expr(expr: @ast::expr, &&rcx: @rcx, v: rvt) {
// particular case. There is an extensive comment on the
// function check_cast_for_escaping_regions() in kind.rs
// explaining how it goes about doing that.
for rcx.resolve_node_type(expr.id).each |target_ty| {
match ty::get(*target_ty).sty {
ty::ty_trait(_, _, vstore_slice(trait_region)) => {
let source_ty = rcx.fcx.expr_ty(source);
constrain_regions_in_type(rcx, trait_region,
expr.span, source_ty);
}
_ => ()
let target_ty = rcx.resolve_node_type(expr.id);
match ty::get(target_ty).sty {
ty::ty_trait(_, _, vstore_slice(trait_region)) => {
let source_ty = rcx.fcx.expr_ty(source);
constrain_regions_in_type(rcx, trait_region,
expr.span, source_ty);
}
_ => ()
}
}
@ -271,16 +276,15 @@ fn visit_expr(expr: @ast::expr, &&rcx: @rcx, v: rvt) {
}
ast::expr_fn(*) | ast::expr_fn_block(*) => {
for rcx.resolve_node_type(expr.id).each |function_type| {
match ty::get(*function_type).sty {
ty::ty_fn(ref fn_ty) => {
if fn_ty.meta.proto == ast::ProtoBorrowed {
constrain_free_variables(
rcx, fn_ty.meta.region, expr);
}
let function_type = rcx.resolve_node_type(expr.id);
match ty::get(function_type).sty {
ty::ty_fn(ref fn_ty) => {
if fn_ty.meta.proto == ast::ProtoBorrowed {
constrain_free_variables(
rcx, fn_ty.meta.region, expr);
}
_ => ()
}
_ => ()
}
}
@ -409,15 +413,10 @@ fn constrain_regions_in_type_of_node(
// Try to resolve the type. If we encounter an error, then typeck
// is going to fail anyway, so just stop here and let typeck
// report errors later on in the writeback phase.
let ty = match rcx.resolve_node_type(id) {
None => { return true; }
Some(ty) => { ty }
};
let ty = rcx.resolve_node_type(id);
debug!("constrain_regions_in_type_of_node(\
ty=%s, id=%d, encl_region=%?)",
ty_to_str(tcx, ty), id, encl_region);
constrain_regions_in_type(rcx, encl_region, span, ty)
}
@ -567,6 +566,30 @@ mod guarantor {
}
}
pub fn for_autoref(rcx: @rcx,
expr: @ast::expr,
adjustment: &ty::AutoAdjustment,
autoref: &ty::AutoRef)
{
/*!
*
* Computes the guarantor for an expression that has an
* autoref adjustment and links it to the lifetime of the
* autoref. This is only important when auto re-borrowing
* region pointers.
*/
debug!("guarantor::for_autoref(expr=%s)", rcx.fcx.expr_to_str(expr));
let _i = ::util::common::indenter();
let mut expr_ct = categorize_unadjusted(rcx, expr);
expr_ct = apply_autoderefs(
rcx, expr, adjustment.autoderefs, expr_ct);
for expr_ct.cat.guarantor.each |g| {
infallibly_mk_subr(rcx, true, expr.span, autoref.region, *g);
}
}
fn link(
rcx: @rcx,
span: span,
@ -589,9 +612,10 @@ mod guarantor {
// this routine is used for the result of ref bindings and &
// expressions, both of which always yield a region variable, so
// mk_subr should never fail.
for rcx.resolve_node_type(id).each |rptr_ty| {
debug!("rptr_ty=%s", ty_to_str(rcx.fcx.ccx.tcx, *rptr_ty));
let r = ty::ty_region(*rptr_ty);
let rptr_ty = rcx.resolve_node_type(id);
if !ty::type_contains_err(rptr_ty) {
debug!("rptr_ty=%s", ty_to_str(rcx.fcx.ccx.tcx, rptr_ty));
let r = ty::ty_region(rptr_ty);
infallibly_mk_subr(rcx, true, span, r, bound);
}
}
@ -608,6 +632,11 @@ mod guarantor {
pointer: PointerCat
}
struct ExprCategorizationType {
cat: ExprCategorization,
ty: ty::t
}
fn guarantor(rcx: @rcx, expr: @ast::expr) -> Option<ty::Region> {
debug!("guarantor(expr=%s)", rcx.fcx.expr_to_str(expr));
match expr.node {
@ -683,52 +712,76 @@ mod guarantor {
debug!("categorize(expr=%s)", rcx.fcx.expr_to_str(expr));
let _i = ::util::common::indenter();
let tcx = rcx.fcx.ccx.tcx;
if rcx.fcx.ccx.method_map.contains_key(expr.id) {
debug!("method call");
return id_categorization(rcx, None, expr.id);
}
let expr_ty = match rcx.resolve_node_type(expr.id) {
None => { return id_categorization(rcx, None, expr.id); }
Some(t) => { t }
};
let mut cat = ExprCategorization {
guarantor: guarantor(rcx, expr),
pointer: pointer_categorize(expr_ty)
};
debug!("before adjustments, cat=%?", cat);
let mut expr_ct = categorize_unadjusted(rcx, expr);
debug!("before adjustments, cat=%?", expr_ct.cat);
for rcx.fcx.inh.adjustments.find(expr.id).each |adjustment| {
debug!("adjustment=%?", adjustment);
for uint::range(0, adjustment.autoderefs) |_| {
cat.guarantor = guarantor_of_deref(&cat);
match ty::deref(tcx, expr_ty, true) {
Some(t) => {
cat.pointer = pointer_categorize(t.ty);
}
None => {
tcx.sess.span_bug(
expr.span,
fmt!("Autoderef but type not derefable: %s",
ty_to_str(tcx, expr_ty)));
}
}
debug!("autoderef, cat=%?", cat);
}
expr_ct = apply_autoderefs(
rcx, expr, adjustment.autoderefs, expr_ct);
for adjustment.autoref.each |autoref| {
cat.guarantor = None;
cat.pointer = BorrowedPointer(autoref.region);
debug!("autoref, cat=%?", cat);
expr_ct.cat.guarantor = None;
expr_ct.cat.pointer = BorrowedPointer(autoref.region);
debug!("autoref, cat=%?", expr_ct.cat);
}
}
debug!("result=%?", cat);
return cat;
debug!("result=%?", expr_ct.cat);
return expr_ct.cat;
}
fn categorize_unadjusted(rcx: @rcx,
expr: @ast::expr) -> ExprCategorizationType {
debug!("categorize_unadjusted(expr=%s)", rcx.fcx.expr_to_str(expr));
let _i = ::util::common::indenter();
let guarantor = {
if rcx.fcx.ccx.method_map.contains_key(expr.id) {
None
} else {
guarantor(rcx, expr)
}
};
let expr_ty = rcx.resolve_node_type(expr.id);
ExprCategorizationType {
cat: ExprCategorization {
guarantor: guarantor,
pointer: pointer_categorize(expr_ty)
},
ty: expr_ty
}
}
fn apply_autoderefs(
+rcx: @rcx,
+expr: @ast::expr,
+autoderefs: uint,
+ct: ExprCategorizationType) -> ExprCategorizationType
{
let mut ct = ct;
let tcx = rcx.fcx.ccx.tcx;
for uint::range(0, autoderefs) |_| {
ct.cat.guarantor = guarantor_of_deref(&ct.cat);
match ty::deref(tcx, ct.ty, true) {
Some(mt) => {
ct.ty = mt.ty;
ct.cat.pointer = pointer_categorize(ct.ty);
}
None => {
tcx.sess.span_bug(
expr.span,
fmt!("Autoderef but type not derefable: %s",
ty_to_str(tcx, ct.ty)));
}
}
debug!("autoderef, cat=%?", ct.cat);
}
return ct;
}
fn pointer_categorize(ty: ty::t) -> PointerCat {
@ -752,19 +805,6 @@ mod guarantor {
}
}
fn id_categorization(rcx: @rcx,
guarantor: Option<ty::Region>,
id: ast::node_id) -> ExprCategorization
{
let pointer = match rcx.resolve_node_type(id) {
None => NotPointer,
Some(t) => pointer_categorize(t)
};
ExprCategorization {guarantor: guarantor,
pointer: pointer}
}
fn guarantor_of_deref(cat: &ExprCategorization) -> Option<ty::Region> {
match cat.pointer {
NotPointer => cat.guarantor,
@ -824,16 +864,18 @@ mod guarantor {
link_ref_bindings_in_pat(rcx, p, guarantor)
}
ast::pat_region(p) => {
for rcx.resolve_node_type(pat.id).each |rptr_ty| {
let r = ty::ty_region(*rptr_ty);
let rptr_ty = rcx.resolve_node_type(pat.id);
if !ty::type_contains_err(rptr_ty) {
let r = ty::ty_region(rptr_ty);
link_ref_bindings_in_pat(rcx, p, Some(r));
}
}
ast::pat_lit(*) => {}
ast::pat_range(*) => {}
ast::pat_vec(ref ps, ref opt_tail_pat) => {
for rcx.resolve_node_type(pat.id).each |vec_ty| {
let vstore = ty::ty_vstore(*vec_ty);
let vec_ty = rcx.resolve_node_type(pat.id);
if !ty::type_contains_err(vec_ty) {
let vstore = ty::ty_vstore(vec_ty);
let guarantor1 = match vstore {
ty::vstore_fixed(_) | ty::vstore_uniq => guarantor,
ty::vstore_slice(r) => Some(r),