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in operator shouldn't narrow {} originating in unknown (#50610)
* 'in' operator shouldn't narrow {} originating in unknown

* Add regression test
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ahejlsberg committed Sep 2, 2022
1 parent 549e61d commit 854d448e5ccf542a05d0b5dcb97e1b925905e258
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Showing 5 changed files with 130 additions and 1 deletion.
@@ -25150,7 +25150,7 @@ namespace ts {

function narrowByInKeyword(type: Type, name: __String, assumeTrue: boolean) {
if (type.flags & TypeFlags.Union
|| type.flags & TypeFlags.Object && declaredType !== type
|| type.flags & TypeFlags.Object && declaredType !== type && !(declaredType === unknownType && isEmptyAnonymousObjectType(type))
|| isThisTypeParameter(type)
|| type.flags & TypeFlags.Intersection && every((type as IntersectionType).types, t => t.symbol !== globalThisSymbol)) {
return filterType(type, t => isTypePresencePossible(t, name, assumeTrue));
@@ -0,0 +1,36 @@
//// [inKeywordAndUnknown.ts]
// Repro from #50531

function f(x: {}, y: unknown) {
if (!("a" in x)) {
return;
}
x; // {}
if (!y) {
return;
}
y; // {}
if (!("a" in y)) {
return;
}
y; // {}
}


//// [inKeywordAndUnknown.js]
"use strict";
// Repro from #50531
function f(x, y) {
if (!("a" in x)) {
return;
}
x; // {}
if (!y) {
return;
}
y; // {}
if (!("a" in y)) {
return;
}
y; // {}
}
@@ -0,0 +1,33 @@
=== tests/cases/compiler/inKeywordAndUnknown.ts ===
// Repro from #50531

function f(x: {}, y: unknown) {
>f : Symbol(f, Decl(inKeywordAndUnknown.ts, 0, 0))
>x : Symbol(x, Decl(inKeywordAndUnknown.ts, 2, 11))
>y : Symbol(y, Decl(inKeywordAndUnknown.ts, 2, 17))

if (!("a" in x)) {
>x : Symbol(x, Decl(inKeywordAndUnknown.ts, 2, 11))

return;
}
x; // {}
>x : Symbol(x, Decl(inKeywordAndUnknown.ts, 2, 11))

if (!y) {
>y : Symbol(y, Decl(inKeywordAndUnknown.ts, 2, 17))

return;
}
y; // {}
>y : Symbol(y, Decl(inKeywordAndUnknown.ts, 2, 17))

if (!("a" in y)) {
>y : Symbol(y, Decl(inKeywordAndUnknown.ts, 2, 17))

return;
}
y; // {}
>y : Symbol(y, Decl(inKeywordAndUnknown.ts, 2, 17))
}

@@ -0,0 +1,42 @@
=== tests/cases/compiler/inKeywordAndUnknown.ts ===
// Repro from #50531

function f(x: {}, y: unknown) {
>f : (x: {}, y: unknown) => void
>x : {}
>y : unknown

if (!("a" in x)) {
>!("a" in x) : boolean
>("a" in x) : boolean
>"a" in x : boolean
>"a" : "a"
>x : {}

return;
}
x; // {}
>x : {}

if (!y) {
>!y : boolean
>y : unknown

return;
}
y; // {}
>y : {}

if (!("a" in y)) {
>!("a" in y) : boolean
>("a" in y) : boolean
>"a" in y : boolean
>"a" : "a"
>y : {}

return;
}
y; // {}
>y : {}
}

@@ -0,0 +1,18 @@
// @strict: true

// Repro from #50531

function f(x: {}, y: unknown) {
if (!("a" in x)) {
return;
}
x; // {}
if (!y) {
return;
}
y; // {}
if (!("a" in y)) {
return;
}
y; // {}
}

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