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fix narrowTypeByDiscriminant for non null expression access #52136

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Merged
merged 3 commits into from
Jan 10, 2023
Merged

fix narrowTypeByDiscriminant for non null expression access #52136

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366f92a
fix narrowTypeByDiscriminant for non null expression access
gabritto Jan 6, 2023
4f4def5
remove comment from test
gabritto Jan 7, 2023
dca634c
don't make prop type optional for non null expression access
gabritto Jan 9, 2023
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6 changes: 4 additions & 2 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -603,6 +603,7 @@ import {
isNewExpression,
isNightly,
isNodeDescendantOf,
isNonNullAccess,
isNullishCoalesce,
isNumericLiteral,
isNumericLiteralName,
Expand Down Expand Up @@ -26299,12 +26300,13 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
if (propName === undefined) {
return type;
}
const removeNullable = strictNullChecks && isOptionalChain(access) && maybeTypeOfKind(type, TypeFlags.Nullable);
const optionalChain = isOptionalChain(access);
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Here we remove null or undefined from the type, but then a few lines below we add back only an undefined. That reflects what happens in an optional chain, but the ! operator never changes one to the other. It may not matter, but doesn't quite seem right.

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I see, I had missed that. So I guess we shouldn't call getOptionalType below if it's a ! operator, since ! actually gets rid of undefined and null, unlike an optional chain.

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@ahejlsberg I pushed the above change, let me know if it's not right or if there's something else missing.

const removeNullable = strictNullChecks && (optionalChain || isNonNullAccess(access)) && maybeTypeOfKind(type, TypeFlags.Nullable);
let propType = getTypeOfPropertyOfType(removeNullable ? getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull) : type, propName);
if (!propType) {
return type;
}
propType = removeNullable ? getOptionalType(propType) : propType;
propType = removeNullable && optionalChain ? getOptionalType(propType) : propType;
const narrowedPropType = narrowType(propType);
return filterType(type, t => {
const discriminantType = getTypeOfPropertyOrIndexSignature(t, propName);
Expand Down
8 changes: 8 additions & 0 deletions src/compiler/utilities.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -295,6 +295,7 @@ import {
isNamespaceExport,
isNamespaceExportDeclaration,
isNamespaceImport,
isNonNullExpression,
isNoSubstitutionTemplateLiteral,
isNumericLiteral,
isObjectLiteralExpression,
Expand Down Expand Up @@ -9482,3 +9483,10 @@ export function isOptionalDeclaration(declaration: Declaration): boolean {
return false;
}
}

/** @internal */
export function isNonNullAccess(node: Node): node is AccessExpression {
const kind = node.kind;
return (kind === SyntaxKind.PropertyAccessExpression
|| kind === SyntaxKind.ElementAccessExpression) && isNonNullExpression((node as AccessExpression).expression);
}
85 changes: 85 additions & 0 deletions tests/baselines/reference/narrowingUnionWithBang.js
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@@ -0,0 +1,85 @@
//// [narrowingUnionWithBang.ts]
type WorkingType = {
thing?:
{ name: 'Error1', message: string } |
{ name: 'Error2', message: string } |
{ name: 'Error3', message: string } |
{ name: 'Error4', message: string } |
{ name: 'Error5', message: string } |
{ name: 'Error6', message: string } |
{ name: 'Error7', message: string } |
{ name: 'Error8', message: string } |
{ name: 'Error9', message: string } |
{ name: 'Correct', id: string }
};
const working: WorkingType = null as unknown as WorkingType;
if (working.thing!.name !== "Correct") {
console.log(working.thing!.message)
} else {
console.log(working.thing!.id);
}

type BorkedType = {
thing?:
{ name: 'Error1', message: string } |
{ name: 'Error2', message: string } |
{ name: 'Error3', message: string } |
{ name: 'Error4', message: string } |
{ name: 'Error5', message: string } |
{ name: 'Error6', message: string } |
{ name: 'Error7', message: string } |
{ name: 'Error8', message: string } |
{ name: 'Correct', id: string }
};
const borked: BorkedType = null as unknown as BorkedType;
if (borked.thing!.name !== "Correct") {
console.log(borked.thing!.message);
} else {
console.log(borked.thing!.id);
}

export type FixedType = {
thing?:
{ name: 'Error1', message: string } |
{ name: 'Error2', message: string } |
{ name: 'Error3', message: string } |
{ name: 'Error4', message: string } |
{ name: 'Error5', message: string } |
{ name: 'Error6', message: string } |
{ name: 'Error7', message: string } |
{ name: 'Error8', message: string } |
{ name: 'Correct', id: string }
};
const fixed: FixedType = null as unknown as FixedType;

if (fixed.thing?.name !== "Correct") {
console.log(fixed.thing!.message);
} else {
console.log(fixed.thing.id);
}

//// [narrowingUnionWithBang.js]
"use strict";
var _a;
Object.defineProperty(exports, "__esModule", { value: true });
var working = null;
if (working.thing.name !== "Correct") {
console.log(working.thing.message);
}
else {
console.log(working.thing.id);
}
var borked = null;
if (borked.thing.name !== "Correct") {
console.log(borked.thing.message);
}
else {
console.log(borked.thing.id);
}
var fixed = null;
if (((_a = fixed.thing) === null || _a === void 0 ? void 0 : _a.name) !== "Correct") {
console.log(fixed.thing.message);
}
else {
console.log(fixed.thing.id);
}
235 changes: 235 additions & 0 deletions tests/baselines/reference/narrowingUnionWithBang.symbols
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@@ -0,0 +1,235 @@
=== tests/cases/compiler/narrowingUnionWithBang.ts ===
type WorkingType = {
>WorkingType : Symbol(WorkingType, Decl(narrowingUnionWithBang.ts, 0, 0))

thing?:
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))

{ name: 'Error1', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 2, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 2, 21))

{ name: 'Error2', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 3, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 3, 21))

{ name: 'Error3', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 4, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 4, 21))

{ name: 'Error4', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 5, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 5, 21))

{ name: 'Error5', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 6, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 6, 21))

{ name: 'Error6', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 7, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 7, 21))

{ name: 'Error7', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 8, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 8, 21))

{ name: 'Error8', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 9, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 9, 21))

{ name: 'Error9', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 10, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 10, 21))

{ name: 'Correct', id: string }
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 11, 5))
>id : Symbol(id, Decl(narrowingUnionWithBang.ts, 11, 22))

};
const working: WorkingType = null as unknown as WorkingType;
>working : Symbol(working, Decl(narrowingUnionWithBang.ts, 13, 5))
>WorkingType : Symbol(WorkingType, Decl(narrowingUnionWithBang.ts, 0, 0))
>WorkingType : Symbol(WorkingType, Decl(narrowingUnionWithBang.ts, 0, 0))

if (working.thing!.name !== "Correct") {
>working.thing!.name : Symbol(name, Decl(narrowingUnionWithBang.ts, 2, 5), Decl(narrowingUnionWithBang.ts, 3, 5), Decl(narrowingUnionWithBang.ts, 4, 5), Decl(narrowingUnionWithBang.ts, 5, 5), Decl(narrowingUnionWithBang.ts, 6, 5) ... and 5 more)
>working.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))
>working : Symbol(working, Decl(narrowingUnionWithBang.ts, 13, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 2, 5), Decl(narrowingUnionWithBang.ts, 3, 5), Decl(narrowingUnionWithBang.ts, 4, 5), Decl(narrowingUnionWithBang.ts, 5, 5), Decl(narrowingUnionWithBang.ts, 6, 5) ... and 5 more)

console.log(working.thing!.message)
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>working.thing!.message : Symbol(message, Decl(narrowingUnionWithBang.ts, 2, 21), Decl(narrowingUnionWithBang.ts, 3, 21), Decl(narrowingUnionWithBang.ts, 4, 21), Decl(narrowingUnionWithBang.ts, 5, 21), Decl(narrowingUnionWithBang.ts, 6, 21) ... and 4 more)
>working.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))
>working : Symbol(working, Decl(narrowingUnionWithBang.ts, 13, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 2, 21), Decl(narrowingUnionWithBang.ts, 3, 21), Decl(narrowingUnionWithBang.ts, 4, 21), Decl(narrowingUnionWithBang.ts, 5, 21), Decl(narrowingUnionWithBang.ts, 6, 21) ... and 4 more)

} else {
console.log(working.thing!.id);
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>working.thing!.id : Symbol(id, Decl(narrowingUnionWithBang.ts, 11, 22))
>working.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))
>working : Symbol(working, Decl(narrowingUnionWithBang.ts, 13, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 0, 20))
>id : Symbol(id, Decl(narrowingUnionWithBang.ts, 11, 22))
}

type BorkedType = {
>BorkedType : Symbol(BorkedType, Decl(narrowingUnionWithBang.ts, 18, 1))

thing?:
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))

{ name: 'Error1', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 22, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 22, 21))

{ name: 'Error2', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 23, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 23, 21))

{ name: 'Error3', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 24, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 24, 21))

{ name: 'Error4', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 25, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 25, 21))

{ name: 'Error5', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 26, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 26, 21))

{ name: 'Error6', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 27, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 27, 21))

{ name: 'Error7', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 28, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 28, 21))

{ name: 'Error8', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 29, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 29, 21))

{ name: 'Correct', id: string }
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 30, 5))
>id : Symbol(id, Decl(narrowingUnionWithBang.ts, 30, 22))

};
const borked: BorkedType = null as unknown as BorkedType;
>borked : Symbol(borked, Decl(narrowingUnionWithBang.ts, 32, 5))
>BorkedType : Symbol(BorkedType, Decl(narrowingUnionWithBang.ts, 18, 1))
>BorkedType : Symbol(BorkedType, Decl(narrowingUnionWithBang.ts, 18, 1))

if (borked.thing!.name !== "Correct") {
>borked.thing!.name : Symbol(name, Decl(narrowingUnionWithBang.ts, 22, 5), Decl(narrowingUnionWithBang.ts, 23, 5), Decl(narrowingUnionWithBang.ts, 24, 5), Decl(narrowingUnionWithBang.ts, 25, 5), Decl(narrowingUnionWithBang.ts, 26, 5) ... and 4 more)
>borked.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))
>borked : Symbol(borked, Decl(narrowingUnionWithBang.ts, 32, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 22, 5), Decl(narrowingUnionWithBang.ts, 23, 5), Decl(narrowingUnionWithBang.ts, 24, 5), Decl(narrowingUnionWithBang.ts, 25, 5), Decl(narrowingUnionWithBang.ts, 26, 5) ... and 4 more)

console.log(borked.thing!.message);
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>borked.thing!.message : Symbol(message, Decl(narrowingUnionWithBang.ts, 22, 21), Decl(narrowingUnionWithBang.ts, 23, 21), Decl(narrowingUnionWithBang.ts, 24, 21), Decl(narrowingUnionWithBang.ts, 25, 21), Decl(narrowingUnionWithBang.ts, 26, 21) ... and 3 more)
>borked.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))
>borked : Symbol(borked, Decl(narrowingUnionWithBang.ts, 32, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 22, 21), Decl(narrowingUnionWithBang.ts, 23, 21), Decl(narrowingUnionWithBang.ts, 24, 21), Decl(narrowingUnionWithBang.ts, 25, 21), Decl(narrowingUnionWithBang.ts, 26, 21) ... and 3 more)

} else {
console.log(borked.thing!.id);
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>borked.thing!.id : Symbol(id, Decl(narrowingUnionWithBang.ts, 30, 22))
>borked.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))
>borked : Symbol(borked, Decl(narrowingUnionWithBang.ts, 32, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 20, 19))
>id : Symbol(id, Decl(narrowingUnionWithBang.ts, 30, 22))
}

export type FixedType = {
>FixedType : Symbol(FixedType, Decl(narrowingUnionWithBang.ts, 37, 1))

thing?:
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))

{ name: 'Error1', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 41, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 41, 21))

{ name: 'Error2', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 42, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 42, 21))

{ name: 'Error3', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 43, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 43, 21))

{ name: 'Error4', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 44, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 44, 21))

{ name: 'Error5', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 45, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 45, 21))

{ name: 'Error6', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 46, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 46, 21))

{ name: 'Error7', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 47, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 47, 21))

{ name: 'Error8', message: string } |
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 48, 5))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 48, 21))

{ name: 'Correct', id: string }
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 49, 5))
>id : Symbol(id, Decl(narrowingUnionWithBang.ts, 49, 22))

};
const fixed: FixedType = null as unknown as FixedType;
>fixed : Symbol(fixed, Decl(narrowingUnionWithBang.ts, 51, 5))
>FixedType : Symbol(FixedType, Decl(narrowingUnionWithBang.ts, 37, 1))
>FixedType : Symbol(FixedType, Decl(narrowingUnionWithBang.ts, 37, 1))

if (fixed.thing?.name !== "Correct") {
>fixed.thing?.name : Symbol(name, Decl(narrowingUnionWithBang.ts, 41, 5), Decl(narrowingUnionWithBang.ts, 42, 5), Decl(narrowingUnionWithBang.ts, 43, 5), Decl(narrowingUnionWithBang.ts, 44, 5), Decl(narrowingUnionWithBang.ts, 45, 5) ... and 4 more)
>fixed.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))
>fixed : Symbol(fixed, Decl(narrowingUnionWithBang.ts, 51, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))
>name : Symbol(name, Decl(narrowingUnionWithBang.ts, 41, 5), Decl(narrowingUnionWithBang.ts, 42, 5), Decl(narrowingUnionWithBang.ts, 43, 5), Decl(narrowingUnionWithBang.ts, 44, 5), Decl(narrowingUnionWithBang.ts, 45, 5) ... and 4 more)

console.log(fixed.thing!.message);
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>fixed.thing!.message : Symbol(message, Decl(narrowingUnionWithBang.ts, 41, 21), Decl(narrowingUnionWithBang.ts, 42, 21), Decl(narrowingUnionWithBang.ts, 43, 21), Decl(narrowingUnionWithBang.ts, 44, 21), Decl(narrowingUnionWithBang.ts, 45, 21) ... and 3 more)
>fixed.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))
>fixed : Symbol(fixed, Decl(narrowingUnionWithBang.ts, 51, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))
>message : Symbol(message, Decl(narrowingUnionWithBang.ts, 41, 21), Decl(narrowingUnionWithBang.ts, 42, 21), Decl(narrowingUnionWithBang.ts, 43, 21), Decl(narrowingUnionWithBang.ts, 44, 21), Decl(narrowingUnionWithBang.ts, 45, 21) ... and 3 more)

} else {
console.log(fixed.thing.id);
>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
>fixed.thing.id : Symbol(id, Decl(narrowingUnionWithBang.ts, 49, 22))
>fixed.thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))
>fixed : Symbol(fixed, Decl(narrowingUnionWithBang.ts, 51, 5))
>thing : Symbol(thing, Decl(narrowingUnionWithBang.ts, 39, 25))
>id : Symbol(id, Decl(narrowingUnionWithBang.ts, 49, 22))
}
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