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rustc: Check patterns before arm blocks in alt expressions; this will be needed for binding type resolution

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This commit is contained in:
Patrick Walton 2010-12-13 16:39:35 -08:00
parent 29e6d7a4ad
commit 0ef65780ca
1 changed files with 32 additions and 10 deletions
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42
src/comp/middle/typeck.rs
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@ -1581,6 +1581,10 @@ fn check_expr(&fn_ctxt fcx, @ast.expr expr) -> @ast.expr {
check (fcx.ccx.item_types.contains_key(variant_id));
t = fcx.ccx.item_types.get(variant_id);
}
case (ast.def_binding(?id)) {
check (fcx.locals.contains_key(id));
t = fcx.locals.get(id);
}
case (_) {
// FIXME: handle other names.
fcx.ccx.sess.unimpl("definition variant for: "
@ -1674,30 +1678,48 @@ fn check_expr(&fn_ctxt fcx, @ast.expr expr) -> @ast.expr {
case (ast.expr_alt(?expr, ?arms, _)) {
auto expr_0 = check_expr(fcx, expr);
auto pattern_ty = expr_ty(expr_0);
auto result_ty = next_ty_var(fcx);
let vec[ast.arm] arms_0 = vec();
// Typecheck the patterns first, so that we get types for all the
// bindings.
auto pattern_ty = expr_ty(expr_0);
let vec[@ast.pat] pats_0 = vec();
for (ast.arm arm in arms) {
auto pat_0 = check_pat(fcx, arm.pat);
pattern_ty = demand(fcx, pat_0.span, pattern_ty,
pat_ty(pat_0));
pats_0 += vec(pat_0);
}
let vec[@ast.pat] pats_1 = vec();
for (@ast.pat pat_0 in pats_0) {
pats_1 += vec(demand_pat(fcx, pattern_ty, pat_0));
}
// Now typecheck the blocks.
auto result_ty = next_ty_var(fcx);
let vec[ast.block] blocks_0 = vec();
for (ast.arm arm in arms) {
auto block_0 = check_block(fcx, arm.block);
result_ty = demand(fcx, block_0.span, result_ty,
block_ty(block_0));
arms_0 += vec(rec(pat=pat_0, block=block_0, index=arm.index));
blocks_0 += vec(block_0);
}
auto expr_1 = demand_expr(fcx, pattern_ty, expr);
let vec[ast.arm] arms_1 = vec();
for (ast.arm arm_0 in arms_0) {
auto pat_1 = demand_pat(fcx, pattern_ty, arm_0.pat);
auto block_1 = demand_block(fcx, result_ty, arm_0.block);
auto arm_1 = rec(pat=pat_1, block=block_1, index=arm_0.index);
auto i = 0u;
for (ast.block block_0 in blocks_0) {
auto block_1 = demand_block(fcx, result_ty, block_0);
auto pat_1 = pats_1.(i);
auto arm = arms.(i);
auto arm_1 = rec(pat=pat_1, block=block_1, index=arm.index);
arms_1 += vec(arm_1);
i += 1u;
}
auto expr_1 = demand_expr(fcx, pattern_ty, expr_0);
auto ann = ast.ann_type(result_ty);
ret @fold.respan[ast.expr_](expr.span,
ast.expr_alt(expr_1, arms_1, ann));