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Multiple updates to the kind inferencer

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- Clean up some code
 - Ensure more syntax is covered during kind inference
 - Make wrongly kinded types not trigger another typing error in the
   next layer
This commit is contained in:
Sam Vervaeck 2022-09-15 22:39:20 +02:00
parent 4939ee5e08
commit 9221441aa4
2 changed files with 130 additions and 92 deletions
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138
src/checker.ts
View file

@ -425,8 +425,14 @@ class KVSub {
}
const enum KindFlags {
UnificationFailed = 1,
}
abstract class KindBase {
public flags: KindFlags = 0;
public abstract readonly type: KindType;
public abstract substitute(sub: KVSub): Kind;
@ -449,6 +455,10 @@ class KVar extends KindBase {
? this : other.substitute(sub);
}
public hasFailed(): boolean {
return true;
}
}
class KStar extends KindBase {
@ -459,6 +469,10 @@ class KStar extends KindBase {
return this;
}
public hasFailed(): boolean {
return (this.flags & KindFlags.UnificationFailed) > 0;
}
}
class KArrow extends KindBase {
@ -472,6 +486,12 @@ class KArrow extends KindBase {
super();
}
public hasFailed(): boolean {
return this.flags & KindFlags.UnificationFailed
|| this.left.hasFailed()
|| this.right.hasFailed();
}
public substitute(sub: KVSub): Kind {
return new KArrow(
this.left.substitute(sub),
@ -819,6 +839,7 @@ export class Checker {
}
private inferKindFromTypeExpression(node: TypeExpression, env: KindEnv): Kind {
let kind: Kind;
switch (node.kind) {
case SyntaxKind.ArrowTypeExpression:
{
@ -826,34 +847,40 @@ export class Checker {
this.unifyKind(this.inferKindFromTypeExpression(param, env), new KStar(), node);
}
this.unifyKind(this.inferKindFromTypeExpression(node.returnTypeExpr, env), new KStar(), node);
return new KStar();
kind = new KStar();
break;
}
case SyntaxKind.VarTypeExpression:
case SyntaxKind.ReferenceTypeExpression:
{
const kind = env.lookup(node.name.text);
if (kind === null) {
const matchedKind = env.lookup(node.name.text);
if (matchedKind === null) {
this.diagnostics.add(new BindingNotFoudDiagnostic(node.name.text, node.name));
// Create a filler kind variable that still will be able to catch other errors.
return this.createKindVar();
kind = this.createKindVar();
} else {
kind = matchedKind;
}
return kind;
break;
}
case SyntaxKind.AppTypeExpression:
{
let result = this.inferKindFromTypeExpression(node.operator, env);
kind = this.inferKindFromTypeExpression(node.operator, env);
for (const arg of node.args) {
result = this.applyKind(result, this.inferKindFromTypeExpression(arg, env), node);
kind = this.applyKind(kind, this.inferKindFromTypeExpression(arg, env), node);
}
return result;
break;
}
case SyntaxKind.NestedTypeExpression:
{
return this.inferKindFromTypeExpression(node.typeExpr, env);
kind = this.inferKindFromTypeExpression(node.typeExpr, env);
break;
}
default:
throw new Error(`Unexpected ${node}`);
}
node.inferredKind = kind;
return kind;
}
private createKindVar(): KVar {
@ -907,7 +934,19 @@ export class Checker {
}
break;
}
case SyntaxKind.TypeDeclaration:
{
const innerEnv = new KindEnv(env);
let kind: Kind = new KStar();
for (let i = node.varExps.length-1; i >= 0; i--) {
const varExpr = node.varExps[i];
const paramKind = this.createKindVar();
innerEnv.setNamed(varExpr.text, paramKind);
kind = new KArrow(paramKind, kind);
}
env.setNamed(node.name.text, this.inferKindFromTypeExpression(node.typeExpression, innerEnv));
break;
}
case SyntaxKind.StructDeclaration:
{
env.setNamed(node.name.text, this.createKindVar());
@ -979,7 +1018,15 @@ export class Checker {
}
break;
}
// TODO
case SyntaxKind.EnumDeclarationStructElement:
{
for (const field of member.fields) {
this.unifyKind(this.inferKindFromTypeExpression(field.typeExpr, innerEnv), new KStar(), field.typeExpr);
}
break;
}
default:
throw new Error(`Unexpected ${member}`);
}
}
}
@ -1037,6 +1084,8 @@ export class Checker {
&& this.unifyKind(a.right, b.right, node);
}
a.flags |= KindFlags.UnificationFailed;
b.flags |= KindFlags.UnificationFailed;
this.diagnostics.add(new KindMismatchDiagnostic(solve(a), solve(b), node));
return false;
}
@ -1166,7 +1215,7 @@ export class Checker {
const scope = node.getScope();
const target = scope.lookup(node.name.text);
if (target !== null && target.kind === SyntaxKind.LetDeclaration && target.active) {
return target.type!;
return target.inferredType!;
}
const scheme = this.lookup(node.name.text, Symkind.Var);
if (scheme === null) {
@ -1229,31 +1278,6 @@ export class Checker {
return ty;
}
case SyntaxKind.NamedTupleExpression:
{
// TODO Only lookup constructors and skip other bindings
const scheme = this.lookup(node.name.text, Symkind.Var);
if (scheme === null) {
this.diagnostics.add(new BindingNotFoudDiagnostic(node.name.text, node.name));
return this.createTypeVar();
}
const operatorType = this.instantiate(scheme, node.name);
const argTypes = node.elements.map(el => this.inferExpression(el));
const retType = this.createTypeVar();
this.addConstraint(
new CEqual(
new TArrow(
argTypes,
retType,
node,
),
operatorType,
node
)
);
return retType;
}
case SyntaxKind.StructExpression:
{
const fields = new Map();
@ -1314,6 +1338,14 @@ export class Checker {
public inferTypeExpression(node: TypeExpression, introduceTypeVars = false): Type {
let type;
if (node.inferredKind!.substitute(this.kindSolution).hasFailed()) {
type = this.createTypeVar();
} else {
switch (node.kind) {
case SyntaxKind.ReferenceTypeExpression:
@ -1323,10 +1355,10 @@ export class Checker {
this.diagnostics.add(new BindingNotFoudDiagnostic(node.name.text, node.name));
return this.createTypeVar();
}
const type = this.instantiate(scheme, node.name);
type = this.instantiate(scheme, node.name);
// FIXME it is not guaranteed that `type` is copied, so the original type might get mutated
type.node = node;
return type;
break;
}
case SyntaxKind.NestedTypeExpression:
@ -1339,21 +1371,23 @@ export class Checker {
if (!introduceTypeVars) {
this.diagnostics.add(new BindingNotFoudDiagnostic(node.name.text, node.name));
}
const type = this.createTypeVar();
type = this.createTypeVar();
this.addBinding(node.name.text, new Forall([], [], type), Symkind.Type);
return type;
}
} else {
assert(isEmpty(scheme.typeVars));
assert(isEmpty(scheme.constraints));
return scheme.type;
type = scheme.type;
}
break;
}
case SyntaxKind.AppTypeExpression:
{
return TApp.build(
type = TApp.build(
this.inferTypeExpression(node.operator, introduceTypeVars),
node.args.map(arg => this.inferTypeExpression(arg, introduceTypeVars)),
);
break;
}
case SyntaxKind.ArrowTypeExpression:
@ -1363,7 +1397,8 @@ export class Checker {
paramTypes.push(this.inferTypeExpression(paramTypeExpr, introduceTypeVars));
}
const returnType = this.inferTypeExpression(node.returnTypeExpr, introduceTypeVars);
return new TArrow(paramTypes, returnType, node);
type = new TArrow(paramTypes, returnType, node);
break;
}
default:
@ -1373,6 +1408,12 @@ export class Checker {
}
node.inferredType = type;
return type;
}
public inferBindings(pattern: Pattern, typeVars: Iterable<TVar>, constraints: Iterable<Constraint>): Type {
switch (pattern.kind) {
@ -1568,15 +1609,14 @@ export class Checker {
}
const fields = new Map<string, Type>();
if (node.fields !== null) {
for (const member of node.fields) {
fields.set(member.name.text, this.inferTypeExpression(member.typeExpr));
for (const field of node.fields) {
fields.set(field.name.text, this.inferTypeExpression(field.typeExpr));
}
}
this.popContext(context);
const type = new TNominal(node);
parentEnv.add(node.name.text, new Forall(typeVars, constraints, type), Symkind.Type);
parentEnv.add(node.name.text, new Forall(typeVars, constraints, new TArrow([ new TRecord(fields, node) ], TApp.build(type, kindArgs))), Symkind.Var);
//node.scheme = new Forall(typeVars, constraints, );
break;
}
@ -1679,7 +1719,7 @@ export class Checker {
)
);
}
node.type = type;
node.inferredType = type;
this.contexts.pop();

12
src/cst.ts
View file

@ -1,5 +1,5 @@
import { JSONObject, JSONValue, MultiMap } from "./util";
import type { InferContext, Scheme, Type, TypeEnv } from "./checker"
import type { InferContext, Kind, Scheme, Type, TypeEnv } from "./checker"
export type TextSpan = [number, number];
@ -351,12 +351,12 @@ export class Scope {
}
abstract class SyntaxBase {
public parent: Syntax | null = null;
public abstract readonly kind: SyntaxKind;
public inferredKind?: Kind;
public inferredType?: Type;
public abstract getFirstToken(): Token;
@ -1826,7 +1826,6 @@ export class StructDeclaration extends SyntaxBase {
public readonly kind = SyntaxKind.StructDeclaration;
public typeEnv?: TypeEnv;
public scheme?: Scheme;
public constructor(
public pubKeyword: PubKeyword | null,
@ -1954,7 +1953,6 @@ export class TypeDeclaration extends SyntaxBase {
public readonly kind = SyntaxKind.TypeDeclaration;
public scheme?: Scheme;
public typeEnv?: TypeEnv;
public constructor(
@ -1986,9 +1984,9 @@ export class LetDeclaration extends SyntaxBase {
public readonly kind = SyntaxKind.LetDeclaration;
public scope?: Scope;
public type?: Type;
public active?: boolean;
public typeEnv?: TypeEnv;
public active?: boolean;
public context?: InferContext;
public constructor(