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feat(kernel/conveter): improve support for proof irrelevant in the converter

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2014-08-25 11:19:18 -07:00
parent 4a9e48d249
commit 04d9eb17d1
2 changed files with 30 additions and 2 deletions
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17
src/kernel/converter.cpp
View file

@ -571,13 +571,26 @@ struct default_converter : public converter {
if (m_env.prop_proof_irrel()) {
// Proof irrelevance support for Prop (aka Type.{0})
auto tcs = infer_type(c, t);
auto scs = infer_type(c, s);
expr t_type = tcs.first;
expr s_type = scs.first;
// remark: is_prop returns true only if t_type reducible to Prop.
// If t_type contains metavariables, then reduction can get stuck, and is_prop will return false.
auto pcs = is_prop(t_type, c);
if (pcs.first) {
auto scs = infer_type(c, s);
auto dcs = is_def_eq(t_type, scs.first, c, jst);
auto dcs = is_def_eq(t_type, s_type, c, jst);
if (dcs.first)
return to_bcs(true, dcs.second + scs.second + pcs.second + tcs.second);
} else {
// If we can't stablish whether t_type is Prop, we try s_type.
pcs = is_prop(s_type, c);
if (pcs.first) {
auto dcs = is_def_eq(t_type, s_type, c, jst);
if (dcs.first)
return to_bcs(true, dcs.second + scs.second + pcs.second + tcs.second);
}
// This procedure will miss the case where s_type and t_type cannot be reduced to Prop
// because they contain metavariables.
}
}

15
tests/lean/run/matrix2.lean Normal file
View file

@ -0,0 +1,15 @@
import logic
variable matrix.{l} : Type.{l} → Type.{l}
variable same_dim {A : Type} : matrix A → matrix A → Prop
variable add {A : Type} (m1 m2 : matrix A) {H : same_dim m1 m2} : matrix A
theorem same_dim_eq_args {A : Type} {m1 m2 m1' m2' : matrix A} (H1 : m1 = m1') (H2 : m2 = m2') (H : same_dim m1 m2) : same_dim m1' m2' :=
subst H1 (subst H2 H)
theorem add_congr {A : Type} (m1 m2 m1' m2' : matrix A) (H1 : m1 = m1') (H2 : m2 = m2') (H : same_dim m1 m2) : @add A m1 m2 H = @add A m1' m2' (same_dim_eq_args H1 H2 H) :=
have base : ∀ (H1 : m1 = m1) (H2 : m2 = m2), @add A m1 m2 H = @add A m1 m2 (eq_rec (eq_rec H H1) H2), from
assume H1 H2, rfl,
have general : ∀ (H1 : m1 = m1') (H2 : m2 = m2'), @add A m1 m2 H = @add A m1' m2' (eq_rec (eq_rec H H1) H2), from
subst H1 (subst H2 base),
general H1 H2