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// @strictNullChecks:true
function onlyErrorsWhenTestingNonNullableFunctionType(required: () => boolean, optional?: () => boolean) {
if (required) { // error
}
if (optional) { // ok
}
if (!!required) { // ok
}
if (required()) { // ok
}
}
function onlyErrorsWhenUnusedInBody() {
function test() { return Math.random() > 0.5; }
if (test) { // error
console.log('test');
}
if (test) { // ok
console.log(test);
}
if (test) { // ok
test();
}
if (test) { // ok
[() => null].forEach(() => {
test();
});
}
if (test) { // error
[() => null].forEach(test => {
test();
});
}
}
function checksPropertyAccess() {
const x = {
foo: {
bar() { return true; }
}
}
if (x.foo.bar) { // error
}
if (x.foo.bar) { // ok
x.foo.bar;
}
}
class Foo {
maybeIsUser?: () => boolean;
isUser() {
return true;
}
test() {
if (this.isUser) { // error
}
if (this.maybeIsUser) { // ok
}
}
}
// Test for GH-35557 where ids were not assigned for a symbol.
function A(stats: StatsBase<any>) {
if (stats.isDirectory) { // err
console.log(`[Directory] ${stats.ctime}`)
}
}
function B(a: Nested, b: Nested) {
if (a.stats.isDirectory) { // err
b.stats.isDirectory();
}
if (a.stats.isDirectory) { // ok
a.stats.isDirectory();
}
}
interface StatsBase<T> {
isDirectory(): boolean;
ctime: number;
}
interface Nested {
stats: StatsBase<any>;
}
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