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Fix instanceof control flow analysis #28112

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Merged
merged 3 commits into from
Oct 25, 2018
Merged

Fix instanceof control flow analysis #28112

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6fbd2a5
Reset narrowing of 'x.y' only when 'x' has a narrowable type
ahejlsberg Oct 24, 2018
ba8310a
Add regression test
ahejlsberg Oct 24, 2018
cc9f45d
Accept new baselines
ahejlsberg Oct 24, 2018
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17 changes: 11 additions & 6 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -14340,6 +14340,11 @@ namespace ts {
return false;
}

function hasNarrowableDeclaredType(expr: Node) {
const type = getDeclaredTypeOfReference(expr);
return !!(type && type.flags & TypeFlags.Union);
}

function findDiscriminantProperties(sourceProperties: Symbol[], target: Type): Symbol[] | undefined {
let result: Symbol[] | undefined;
for (const sourceProperty of sourceProperties) {
Expand Down Expand Up @@ -15373,9 +15378,9 @@ namespace ts {
// We have '==', '!=', '====', or !==' operator with 'typeof xxx' and string literal operands
const target = getReferenceCandidate(typeOfExpr.expression);
if (!isMatchingReference(reference, target)) {
// For a reference of the form 'x.y', a 'typeof x === ...' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, target)) {
// For a reference of the form 'x.y', where 'x' has a narrowable declared type, a
// 'typeof x === ...' type guard resets the narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, target) && hasNarrowableDeclaredType(target)) {
return declaredType;
}
return type;
Expand Down Expand Up @@ -15516,9 +15521,9 @@ namespace ts {
function narrowTypeByInstanceof(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
const left = getReferenceCandidate(expr.left);
if (!isMatchingReference(reference, left)) {
// For a reference of the form 'x.y', an 'x instanceof T' type guard resets the
// narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, left)) {
// For a reference of the form 'x.y', where 'x' has a narrowable declared type, an
// 'x instanceof T' type guard resets the narrowed type of 'y' to its declared type.
if (containsMatchingReference(reference, left) && hasNarrowableDeclaredType(left)) {
return declaredType;
}
return type;
Expand Down
67 changes: 67 additions & 0 deletions tests/baselines/reference/narrowingOfDottedNames.errors.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,67 @@
tests/cases/compiler/narrowingOfDottedNames.ts(45,5): error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
tests/cases/compiler/narrowingOfDottedNames.ts(54,5): error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.


==== tests/cases/compiler/narrowingOfDottedNames.ts (2 errors) ====
// Repro from #8383

class A {
prop!: { a: string; };
}

class B {
prop!: { b: string; }
}

function isA(x: any): x is A {
return x instanceof A;
}

function isB(x: any): x is B {
return x instanceof B;
}

function f1(x: A | B) {
while (true) {
if (x instanceof A) {
x.prop.a;
}
else if (x instanceof B) {
x.prop.b;
}
}
}

function f2(x: A | B) {
while (true) {
if (isA(x)) {
x.prop.a;
}
else if (isB(x)) {
x.prop.b;
}
}
}

// Repro from #28100

class Foo1
{
x: number; // Error
~
!!! error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
constructor() {
if (this instanceof Boolean) {
}
}
}

class Foo2
{
x: number; // Error
~
!!! error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
constructor() {
}
}

36 changes: 34 additions & 2 deletions tests/baselines/reference/narrowingOfDottedNames.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,11 +2,11 @@
// Repro from #8383

class A {
prop: { a: string; };
prop!: { a: string; };
}

class B {
prop: { b: string; }
prop!: { b: string; }
}

function isA(x: any): x is A {
Expand Down Expand Up @@ -38,9 +38,28 @@ function f2(x: A | B) {
}
}
}

// Repro from #28100

class Foo1
{
x: number; // Error
constructor() {
if (this instanceof Boolean) {
}
}
}

class Foo2
{
x: number; // Error
constructor() {
}
}


//// [narrowingOfDottedNames.js]
"use strict";
// Repro from #8383
var A = /** @class */ (function () {
function A() {
Expand Down Expand Up @@ -78,3 +97,16 @@ function f2(x) {
}
}
}
// Repro from #28100
var Foo1 = /** @class */ (function () {
function Foo1() {
if (this instanceof Boolean) {
}
}
return Foo1;
}());
var Foo2 = /** @class */ (function () {
function Foo2() {
}
return Foo2;
}());
50 changes: 38 additions & 12 deletions tests/baselines/reference/narrowingOfDottedNames.symbols
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Original file line number Diff line number Diff line change
Expand Up @@ -4,17 +4,17 @@
class A {
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))

prop: { a: string; };
prop!: { a: string; };
>prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 12))
}

class B {
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

prop: { b: string; }
prop!: { b: string; }
>prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 12))
}

function isA(x: any): x is A {
Expand Down Expand Up @@ -51,22 +51,22 @@ function f1(x: A | B) {
>A : Symbol(A, Decl(narrowingOfDottedNames.ts, 0, 0))

x.prop.a;
>x.prop.a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>x.prop.a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 12))
>x.prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 12))
}
else if (x instanceof B) {
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>B : Symbol(B, Decl(narrowingOfDottedNames.ts, 4, 1))

x.prop.b;
>x.prop.b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>x.prop.b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 12))
>x.prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 18, 12))
>prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 12))
}
}
}
Expand All @@ -83,23 +83,49 @@ function f2(x: A | B) {
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))

x.prop.a;
>x.prop.a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>x.prop.a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 12))
>x.prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))
>prop : Symbol(A.prop, Decl(narrowingOfDottedNames.ts, 2, 9))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 11))
>a : Symbol(a, Decl(narrowingOfDottedNames.ts, 3, 12))
}
else if (isB(x)) {
>isB : Symbol(isB, Decl(narrowingOfDottedNames.ts, 12, 1))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))

x.prop.b;
>x.prop.b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>x.prop.b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 12))
>x.prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>x : Symbol(x, Decl(narrowingOfDottedNames.ts, 29, 12))
>prop : Symbol(B.prop, Decl(narrowingOfDottedNames.ts, 6, 9))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 11))
>b : Symbol(b, Decl(narrowingOfDottedNames.ts, 7, 12))
}
}
}

// Repro from #28100

class Foo1
>Foo1 : Symbol(Foo1, Decl(narrowingOfDottedNames.ts, 38, 1))
{
x: number; // Error
>x : Symbol(Foo1.x, Decl(narrowingOfDottedNames.ts, 43, 1))

constructor() {
if (this instanceof Boolean) {
>this : Symbol(Foo1, Decl(narrowingOfDottedNames.ts, 38, 1))
>Boolean : Symbol(Boolean, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
}
}
}

class Foo2
>Foo2 : Symbol(Foo2, Decl(narrowingOfDottedNames.ts, 49, 1))
{
x: number; // Error
>x : Symbol(Foo2.x, Decl(narrowingOfDottedNames.ts, 52, 1))

constructor() {
}
}

31 changes: 29 additions & 2 deletions tests/baselines/reference/narrowingOfDottedNames.types
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Original file line number Diff line number Diff line change
Expand Up @@ -4,15 +4,15 @@
class A {
>A : A

prop: { a: string; };
prop!: { a: string; };
>prop : { a: string; }
>a : string
}

class B {
>B : B

prop: { b: string; }
prop!: { b: string; }
>prop : { b: string; }
>b : string
}
Expand Down Expand Up @@ -105,3 +105,30 @@ function f2(x: A | B) {
}
}

// Repro from #28100

class Foo1
>Foo1 : Foo1
{
x: number; // Error
>x : number

constructor() {
if (this instanceof Boolean) {
>this instanceof Boolean : boolean
>this : this
>Boolean : BooleanConstructor
}
}
}

class Foo2
>Foo2 : Foo2
{
x: number; // Error
>x : number

constructor() {
}
}

24 changes: 22 additions & 2 deletions tests/cases/compiler/narrowingOfDottedNames.ts
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Original file line number Diff line number Diff line change
@@ -1,11 +1,13 @@
// @strict: true

// Repro from #8383

class A {
prop: { a: string; };
prop!: { a: string; };
}

class B {
prop: { b: string; }
prop!: { b: string; }
}

function isA(x: any): x is A {
Expand Down Expand Up @@ -37,3 +39,21 @@ function f2(x: A | B) {
}
}
}

// Repro from #28100

class Foo1
{
x: number; // Error
constructor() {
if (this instanceof Boolean) {
}
}
}

class Foo2
{
x: number; // Error
constructor() {
}
}