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fix(kernel/type_checker): Pi with metavariables case

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The type checker (and type inferer) were not handling correctly Pi expressions where the type universe cannot be established due to the occurrence of metavariables. In this case, a max-constraint is created. The problem is that the domain and body of the Pi are in different contexts. The constrain generated before this commit was incorrect, it could contain a free variable. This commit fix the issue by using the context of the body, and lifting the free variables in the domain by 1.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-12-06 13:07:33 -08:00
parent fa03ae2a26
commit d79a626523
2 changed files with 4 additions and 4 deletions
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4
src/kernel/type_checker.cpp
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@ -173,9 +173,9 @@ class type_checker::imp {
case expr_kind::Pi: {
expr t1 = check_type(infer_type_core(abst_domain(e), ctx), abst_domain(e), ctx);
expr t2;
context new_ctx = extend(ctx, abst_name(e), abst_domain(e));
{
cache::mk_scope sc(m_cache);
context new_ctx = extend(ctx, abst_name(e), abst_domain(e));
t2 = check_type(infer_type_core(abst_body(e), new_ctx), abst_body(e), new_ctx);
}
if (is_type(t1) && is_type(t2)) {
@ -184,7 +184,7 @@ class type_checker::imp {
lean_assert(m_uc);
justification jst = mk_max_type_justification(ctx, e);
r = m_menv->mk_metavar(ctx);
m_uc->push_back(mk_max_constraint(ctx, t1, t2, r, jst));
m_uc->push_back(mk_max_constraint(new_ctx, lift_free_vars(t1, 0, 1), t2, r, jst));
}
break;
}

4
src/library/type_inferer.cpp
View file

@ -181,9 +181,9 @@ class type_inferer::imp {
case expr_kind::Pi: {
expr t1 = check_type(infer_type(abst_domain(e), ctx), abst_domain(e), ctx);
expr t2;
context new_ctx = extend(ctx, abst_name(e), abst_domain(e));
{
cache::mk_scope sc(m_cache);
context new_ctx = extend(ctx, abst_name(e), abst_domain(e));
t2 = check_type(infer_type(abst_body(e), new_ctx), abst_body(e), new_ctx);
}
if (is_type(t1) && is_type(t2)) {
@ -192,7 +192,7 @@ class type_inferer::imp {
lean_assert(m_uc);
justification jst = mk_max_type_justification(ctx, e);
r = m_menv->mk_metavar(ctx);
m_uc->push_back(mk_max_constraint(ctx, t1, t2, r, jst));
m_uc->push_back(mk_max_constraint(new_ctx, lift_free_vars(t1, 0, 1), t2, r, jst));
}
break;
}