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tests/cases/conformance/expressions/typeGuards/typeGuardsWithInstanceOf.ts(7,20): error TS2339: Property 'global' does not exist on type 'never'.
The intersection 'I & RegExp' was reduced to 'never' because property 'global' has conflicting types in some constituents.
==== tests/cases/conformance/expressions/typeGuards/typeGuardsWithInstanceOf.ts (1 errors) ====
interface I { global: string; }
var result!: I;
var result2!: I;
if (!(result instanceof RegExp)) {
result = result2;
} else if (!result.global) {
~~~~~~
!!! error TS2339: Property 'global' does not exist on type 'never'.
!!! error TS2339: The intersection 'I & RegExp' was reduced to 'never' because property 'global' has conflicting types in some constituents.
}
// Repro from #31155
interface OnChanges {
onChanges(changes: Record<string, unknown>): void
}
interface Validator {
validate(): null | Record<string, unknown>;
}
class C {
validate() {
return {}
}
}
function foo() {
let v: Validator & Partial<OnChanges> = null as any;
if (v instanceof C) {
v // Validator & Partial<OnChanges> & C
}
v // Validator & Partial<OnChanges> via subtype reduction
if (v.onChanges) {
v.onChanges({});
}
}
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