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Add 'unhandled effects at top-level' error
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@jfecher
jfecher committed Jan 6, 2025
1 parent b2aae73 commit 7541205
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Showing 2 changed files with 37 additions and 26 deletions.
7 changes: 6 additions & 1 deletion src/error/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,7 @@ pub enum DiagnosticKind {
NoMatchingImpls(/*constraint*/ String),
UnreachablePattern,
MissingCase(/*case*/ String),
UnhandledEffectsInMain(/*effects*/ String),
}

#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
Expand Down Expand Up @@ -313,7 +314,7 @@ impl Display for DiagnosticKind {
},
DiagnosticKind::TypeError(TypeErrorKind::MonomorphizationError, actual, expected) => {
unreachable!(
"Unification error during monomorphisation: Could not unify definition {} with instantiation {}",
"Unification error during monomorphization: Could not unify definition {} with instantiation {}",
expected, actual
)
},
Expand All @@ -335,6 +336,9 @@ impl Display for DiagnosticKind {
DiagnosticKind::MissingCase(case) => {
write!(f, "Missing case {case}")
},
DiagnosticKind::UnhandledEffectsInMain(effects) => {
write!(f, "Unhandled effects at top-level: {effects}")
},
}
}
}
Expand Down Expand Up @@ -381,6 +385,7 @@ impl DiagnosticKind {
| InternalError(_)
| NotAStruct(_)
| MissingFields(_)
| UnhandledEffectsInMain(_)
| NotAStructField(_) => Error,
}
}
Expand Down
56 changes: 31 additions & 25 deletions src/types/typechecker.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -244,8 +244,7 @@ pub fn replace_all_typevars_with_bindings(
/// If the given TypeVariableId is unbound then return the matching binding in new_bindings.
/// If there is no binding found, instantiate a new type variable and use that.
fn replace_typevar_with_binding(
id: TypeVariableId, new_bindings: &mut TypeBindings,
cache: &mut ModuleCache<'_>,
id: TypeVariableId, new_bindings: &mut TypeBindings, cache: &mut ModuleCache<'_>,
) -> Type {
if let Bound(typ) = &cache.type_bindings[id.0] {
replace_all_typevars_with_bindings(&typ.clone(), new_bindings, cache)
Expand Down Expand Up @@ -328,10 +327,7 @@ pub fn bind_typevars(typ: &Type, type_bindings: &TypeBindings, cache: &ModuleCac
/// Helper for bind_typevars which binds a single TypeVariableId if it is Unbound
/// and it is found in the type_bindings. If a type_binding wasn't found, a
/// default TypeVariable is constructed.
fn bind_typevar(
id: TypeVariableId, type_bindings: &TypeBindings,
cache: &ModuleCache<'_>,
) -> Type {
fn bind_typevar(id: TypeVariableId, type_bindings: &TypeBindings, cache: &ModuleCache<'_>) -> Type {
// TODO: This ordering of checking type_bindings first is important.
// There seems to be an issue currently where forall-bound variables
// can be bound in the cache, so checking the cache for bindings first
Expand Down Expand Up @@ -369,7 +365,7 @@ pub fn contains_any_typevars_from_list(typ: &Type, list: &[TypeVariableId], cach
contains_any_typevars_from_list(mutability, list, cache)
|| contains_any_typevars_from_list(sharedness, list, cache)
|| contains_any_typevars_from_list(lifetime, list, cache)
}
},

TypeApplication(typ, args) => {
contains_any_typevars_from_list(typ, list, cache)
Expand Down Expand Up @@ -569,8 +565,7 @@ pub(super) fn occurs(
.then_all(&function.parameters, |param| occurs(id, level, param, bindings, fuel, cache)),
TypeApplication(typ, args) => occurs(id, level, typ, bindings, fuel, cache)
.then_all(args, |arg| occurs(id, level, arg, bindings, fuel, cache)),
Ref { mutability, sharedness, lifetime } =>
occurs(id, level, mutability, bindings, fuel, cache)
Ref { mutability, sharedness, lifetime } => occurs(id, level, mutability, bindings, fuel, cache)
.then(|| occurs(id, level, sharedness, bindings, fuel, cache))
.then(|| occurs(id, level, lifetime, bindings, fuel, cache)),
Struct(fields, var_id) => typevars_match(id, level, *var_id, bindings, fuel, cache)
Expand Down Expand Up @@ -628,7 +623,8 @@ pub fn follow_bindings_in_cache(typ: &Type, cache: &ModuleCache<'_>) -> Type {
/// This function performs the bulk of the work for the various unification functions.
#[allow(clippy::nonminimal_bool)]
pub fn try_unify_with_bindings_inner<'b>(
actual: &Type, expected: &Type, bindings: &mut UnificationBindings, location: Location<'b>, cache: &mut ModuleCache<'b>,
actual: &Type, expected: &Type, bindings: &mut UnificationBindings, location: Location<'b>,
cache: &mut ModuleCache<'b>,
) -> Result<(), ()> {
match (actual, expected) {
(Primitive(p1), Primitive(p2)) if p1 == p2 => Ok(()),
Expand All @@ -641,9 +637,13 @@ pub fn try_unify_with_bindings_inner<'b>(
// it to the minimum scope of type variables in b. This happens within the occurs check.
// The unification of the LetBindingLevel here is a form of lifetime inference for the
// typevar and is used during generalization to determine which variables to generalize.
(TypeVariable(id), _) => try_unify_type_variable_with_bindings(*id, actual, expected, true, bindings, location, cache),
(TypeVariable(id), _) => {
try_unify_type_variable_with_bindings(*id, actual, expected, true, bindings, location, cache)
},

(_, TypeVariable(id)) => try_unify_type_variable_with_bindings(*id, expected, actual, false, bindings, location, cache),
(_, TypeVariable(id)) => {
try_unify_type_variable_with_bindings(*id, expected, actual, false, bindings, location, cache)
},

(Function(function1), Function(function2)) => {
if function1.parameters.len() != function2.parameters.len() {
Expand Down Expand Up @@ -683,8 +683,10 @@ pub fn try_unify_with_bindings_inner<'b>(
},

// Refs have a hidden lifetime variable we need to unify here
(Ref { sharedness: a_shared, mutability: a_mut, lifetime: a_lifetime },
Ref { sharedness: b_shared, mutability: b_mut, lifetime: b_lifetime }) => {
(
Ref { sharedness: a_shared, mutability: a_mut, lifetime: a_lifetime },
Ref { sharedness: b_shared, mutability: b_mut, lifetime: b_lifetime },
) => {
try_unify_with_bindings_inner(a_shared, b_shared, bindings, location, cache)?;
try_unify_with_bindings_inner(a_mut, b_mut, bindings, location, cache)?;
try_unify_with_bindings_inner(a_lifetime, b_lifetime, bindings, location, cache)
Expand Down Expand Up @@ -865,10 +867,8 @@ fn get_fields(
/// Unify a single type variable (id arising from the type a) with an expected type b.
/// Follows the given TypeBindings in bindings and the cache if a is Bound.
fn try_unify_type_variable_with_bindings<'c>(
id: TypeVariableId, a: &Type, b: &Type,
typevar_on_lhs: bool,
bindings: &mut UnificationBindings, location: Location<'c>,
cache: &mut ModuleCache<'c>,
id: TypeVariableId, a: &Type, b: &Type, typevar_on_lhs: bool, bindings: &mut UnificationBindings,
location: Location<'c>, cache: &mut ModuleCache<'c>,
) -> Result<(), ()> {
match find_binding(id, bindings, cache) {
Bound(a) => {
Expand All @@ -877,7 +877,7 @@ fn try_unify_type_variable_with_bindings<'c>(
} else {
try_unify_with_bindings_inner(b, &a, bindings, location, cache)
}
}
},
Unbound(a_level, _a_kind) => {
// Create binding for boundTy that is currently empty.
// Ensure not to create recursive bindings to the same variable
Expand All @@ -899,8 +899,8 @@ fn try_unify_type_variable_with_bindings<'c>(
}

pub fn try_unify_with_bindings<'b>(
actual: &Type, expected: &Type, bindings: &mut UnificationBindings, location: Location<'b>, cache: &mut ModuleCache<'b>,
error: TypeErrorKind,
actual: &Type, expected: &Type, bindings: &mut UnificationBindings, location: Location<'b>,
cache: &mut ModuleCache<'b>, error: TypeErrorKind,
) -> Result<(), Diagnostic<'b>> {
match try_unify_with_bindings_inner(actual, expected, bindings, location, cache) {
Ok(()) => Ok(()),
Expand Down Expand Up @@ -945,7 +945,9 @@ pub fn try_unify_all_with_bindings<'c>(

/// Unifies the two given types, remembering the unification results in the cache.
/// If this operation fails, a user-facing error message is emitted.
pub fn unify<'c>(actual: &Type, expected: &Type, location: Location<'c>, cache: &mut ModuleCache<'c>, error_kind: TypeErrorKind) {
pub fn unify<'c>(
actual: &Type, expected: &Type, location: Location<'c>, cache: &mut ModuleCache<'c>, error_kind: TypeErrorKind,
) {
perform_bindings_or_push_error(try_unify(actual, expected, location, cache, error_kind), cache);
}

Expand Down Expand Up @@ -1005,7 +1007,7 @@ pub fn find_all_typevars(typ: &Type, polymorphic_only: bool, cache: &ModuleCache
type_variables.append(&mut find_all_typevars(sharedness, polymorphic_only, cache));
type_variables.append(&mut find_all_typevars(lifetime, polymorphic_only, cache));
type_variables
}
},
Struct(fields, id) => match &cache.type_bindings[id.0] {
Bound(t) => find_all_typevars(t, polymorphic_only, cache),
Unbound(..) => {
Expand Down Expand Up @@ -1489,8 +1491,12 @@ pub fn infer_ast<'a>(ast: &mut ast::Ast<'a>, cache: &mut ModuleCache<'a>) {
// No traits should be propogated above the top-level main function
assert!(exposed_traits.is_empty());

// TODO: Better error message, check for IO effect
assert!(result.effects.effects.is_empty());
// TODO: Check for IO effect
if !result.effects.effects.is_empty() {
let effects = Type::Effects(result.effects.clone());
let effects = effects.display(cache).to_string();
cache.push_diagnostic(ast.locate(), D::UnhandledEffectsInMain(effects));
}
}

pub fn infer<'a, T>(ast: &mut T, cache: &mut ModuleCache<'a>) -> TypeResult
Expand Down

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