language-servers/roc
1
0
Fork 0
mirror of https://github.com/roc-lang/roc.git synced 2025-09-23 03:52:27 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 7

Unification of Any and Openness tag extensions

Browse source
This commit is contained in:
Ayaz Hafiz 2023-01-13 10:33:04 -06:00
parent 1c93727822
commit 281b71cf94
No known key found for this signature in database
GPG key ID: 0E2A37416A25EF58
1 changed files with 53 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

60
crates/compiler/unify/src/unify.rs
View file

@ -2405,6 +2405,41 @@ fn close_uninhabited_extended_union(subs: &mut Subs, mut var: Variable) {
}
}
#[must_use]
fn unify_tag_ext<M: MetaCollector>(
env: &mut Env,
pool: &mut Pool,
ext: TagExt,
var: Variable,
mode: Mode,
) -> Outcome<M> {
let legal_unification = match ext {
TagExt::Openness(_) => {
// Openness extensions can either unify with empty tag unions (marking them as closed),
// or flex/rigids. Anything else is a change in the monomorphic size of the tag and not
// a reflection of the polymorphism of the tag, an error.
match env.subs.get_content_without_compacting(var) {
FlexVar(..) | RigidVar(..) | FlexAbleVar(..) | RigidAbleVar(..) => true,
Structure(s) => match s {
FlatType::EmptyTagUnion => true,
_ => false,
},
Error => {
// errors propagate
true
}
_ => false,
}
}
TagExt::Any(_) => true,
};
if legal_unification {
unify_pool(env, pool, ext.var(), var, mode)
} else {
mismatch!()
}
}
#[allow(clippy::too_many_arguments)]
#[must_use]
fn unify_tag_unions<M: MetaCollector>(
@ -2454,7 +2489,10 @@ fn unify_tag_unions<M: MetaCollector>(
if separate.only_in_1.is_empty() {
if separate.only_in_2.is_empty() {
let ext_outcome = if ctx.mode.is_eq() {
// TODO(openness)
// Neither extension can grow in monomorphic tag sizes,
// so the extension must either be [] or a polymorphic extension variable like `a`.
// As such we can always unify directly even if the extensions are measuring
// openness.
unify_pool(env, pool, ext1.var(), ext2.var(), ctx.mode)
} else {
// In a presence context, we don't care about ext2 being equal to ext1
@ -2500,19 +2538,21 @@ fn unify_tag_unions<M: MetaCollector>(
ext1 = new_ext;
}
let ext_outcome = unify_pool(env, pool, ext1.var(), extra_tags_in_2, ctx.mode);
let ext_outcome = unify_tag_ext(env, pool, ext1, extra_tags_in_2, ctx.mode);
if !ext_outcome.mismatches.is_empty() {
return ext_outcome;
}
let combined_ext = ext1.map(|_| extra_tags_in_2);
let mut shared_tags_outcome = unify_shared_tags(
env,
pool,
ctx,
shared_tags,
OtherTags2::Empty,
ext1.map(|_| extra_tags_in_2),
combined_ext,
recursion_var,
);
@ -2550,7 +2590,7 @@ fn unify_tag_unions<M: MetaCollector>(
ext2 = new_ext;
}
let ext_outcome = unify_pool(env, pool, extra_tags_in_1, ext2.var(), ctx.mode);
let ext_outcome = unify_tag_ext(env, pool, ext2, extra_tags_in_1, ctx.mode);
if !ext_outcome.mismatches.is_empty() {
return ext_outcome;
@ -2562,13 +2602,15 @@ fn unify_tag_unions<M: MetaCollector>(
false
};
let combined_ext = ext2.map(|_| extra_tags_in_1);
let shared_tags_outcome = unify_shared_tags(
env,
pool,
ctx,
shared_tags,
OtherTags2::Empty,
ext2.map(|_| extra_tags_in_1),
combined_ext,
recursion_var,
);
total_outcome.union(shared_tags_outcome);
@ -2589,7 +2631,11 @@ fn unify_tag_unions<M: MetaCollector>(
} else {
Content::FlexVar(None)
};
// If ext1 or ext2 are `Openness`, we will necessarily get an error below when unifying
// the separate tags since `Openness` cannot grow in terms of width of tags. As such, the
// unified type, when it exists, must always be include an `Any` extension.
let ext = TagExt::Any(fresh(env, pool, ctx, ext_content));
let flat_type1 = FlatType::TagUnion(unique_tags1, ext);
let flat_type2 = FlatType::TagUnion(unique_tags2, ext);
@ -2613,7 +2659,7 @@ fn unify_tag_unions<M: MetaCollector>(
let mut total_outcome = Outcome::default();
let snapshot = env.subs.snapshot();
let ext1_outcome = unify_pool(env, pool, ext1.var(), sub2, ctx.mode);
let ext1_outcome = unify_tag_ext(env, pool, ext1, sub2, ctx.mode);
if !ext1_outcome.mismatches.is_empty() {
env.subs.rollback_to(snapshot);
return ext1_outcome;
@ -2621,7 +2667,7 @@ fn unify_tag_unions<M: MetaCollector>(
total_outcome.union(ext1_outcome);
if ctx.mode.is_eq() {
let ext2_outcome = unify_pool(env, pool, sub1, ext2.var(), ctx.mode);
let ext2_outcome = unify_tag_ext(env, pool, ext2, sub1, ctx.mode);
if !ext2_outcome.mismatches.is_empty() {
env.subs.rollback_to(snapshot);
return ext2_outcome;