bjoernager/rust
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Check the declaration type in a for loop against the sequence type

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Changed the typechecker to correctly typecheck the declared variable
type in a for or for-each loop against the vector element type (for
a for loop) or the iterator type (for a for-each loop). Added a
test case.
This commit is contained in:
Tim Chevalier 2011-05-27 17:01:08 -07:00
parent 0c5a55f275
commit b6e0c5829f
2 changed files with 62 additions and 15 deletions
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52
src/comp/middle/typeck.rs
View file

@ -1872,6 +1872,22 @@ fn check_expr(&@stmt_ctxt scx, &@ast::expr expr) {
check_call_or_bind(scx, f, args_opt_0);
}
// A generic function for checking for or for-each loops
fn check_for_or_for_each(&@stmt_ctxt scx, &@ast::decl decl,
&ty::t element_ty, &ast::block body,
uint node_id) {
check_decl_local(scx.fcx, decl);
check_block(scx, body);
// Unify type of decl with element type of the seq
demand::simple(scx, decl.span, ty::decl_local_ty(scx.fcx.ccx.tcx,
decl),
element_ty);
auto typ = ty::mk_nil(scx.fcx.ccx.tcx);
write::ty_only_fixup(scx, node_id, typ);
}
alt (expr.node) {
case (ast::expr_lit(?lit, ?a)) {
auto typ = check_lit(scx.fcx.ccx, lit);
@ -2000,7 +2016,6 @@ fn check_expr(&@stmt_ctxt scx, &@ast::expr expr) {
case (none[@ast::expr]) {
auto nil = ty::mk_nil(scx.fcx.ccx.tcx);
if (!are_compatible(scx, scx.fcx.ret_ty, nil)) {
// TODO: span_err
scx.fcx.ccx.tcx.sess.span_err(expr.span,
"put; in iterator yielding non-nil");
}
@ -2159,24 +2174,33 @@ fn check_expr(&@stmt_ctxt scx, &@ast::expr expr) {
}
case (ast::expr_for(?decl, ?seq, ?body, ?a)) {
check_decl_local(scx.fcx, decl);
check_expr(scx, seq);
check_block(scx, body);
// FIXME: enforce that the type of the decl is the element type
// of the seq.
auto typ = ty::mk_nil(scx.fcx.ccx.tcx);
write::ty_only_fixup(scx, a.id, typ);
alt (struct (scx.fcx.ccx.tcx,
expr_ty(scx.fcx.ccx.tcx, seq))) {
// FIXME: I include the check_for_or_each call in
// each case because of a bug in typestate;
// once that bug is fixed, the call can be moved
// out of the alt expression
case (ty::ty_vec(?vec_elt_ty)) {
auto elt_ty = vec_elt_ty.ty;
check_for_or_for_each(scx, decl, elt_ty, body, a.id);
}
case (ty::ty_str) {
auto elt_ty = ty::mk_mach(scx.fcx.ccx.tcx,
util::common::ty_u8);
check_for_or_for_each(scx, decl, elt_ty, body, a.id);
}
case (_) {
scx.fcx.ccx.tcx.sess.span_err(expr.span,
"type of for loop iterator is not a vector or string");
}
}
}
case (ast::expr_for_each(?decl, ?seq, ?body, ?a)) {
check_decl_local(scx.fcx, decl);
check_expr(scx, seq);
check_block(scx, body);
auto typ = ty::mk_nil(scx.fcx.ccx.tcx);
write::ty_only_fixup(scx, a.id, typ);
check_for_or_for_each(scx, decl, expr_ty(scx.fcx.ccx.tcx, seq),
body, a.id);
}
case (ast::expr_while(?cond, ?body, ?a)) {

23
src/test/compile-fail/for-loop-decl.rs Normal file
View file

@ -0,0 +1,23 @@
// error-pattern: mismatched types
use std;
import std::map::hashmap;
import std::bitv;
type fn_info = rec(hashmap[uint, var_info] vars);
type var_info = rec(uint a, uint b);
fn bitv_to_str(fn_info enclosing, bitv::t v) -> str {
auto s = "";
// error is that the value type in the hash map is var_info, not a tuple
for each (@tup(uint, tup(uint, uint)) p in enclosing.vars.items()) {
if (bitv::get(v, p._1._0)) {
s += "foo"; // " " + p._1._1 + " " + "[" + p._0 + "]";
}
}
ret s;
}
fn main() {
log "OK";
}