Flag non-nullable functions in if statements as errors (tree walk version)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,91 @@ | ||
| tests/cases/compiler/truthinessCallExpressionCoercion.ts(2,9): error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| tests/cases/compiler/truthinessCallExpressionCoercion.ts(18,9): error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| tests/cases/compiler/truthinessCallExpressionCoercion.ts(36,9): error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| tests/cases/compiler/truthinessCallExpressionCoercion.ts(50,9): error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| tests/cases/compiler/truthinessCallExpressionCoercion.ts(66,13): error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
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| ==== tests/cases/compiler/truthinessCallExpressionCoercion.ts (5 errors) ==== | ||
| function onlyErrorsWhenTestingNonNullableFunctionType(required: () => boolean, optional?: () => boolean) { | ||
| if (required) { // error | ||
| ~~~~~~~~ | ||
| !!! error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| } | ||
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| if (optional) { // ok | ||
| } | ||
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| if (!!required) { // ok | ||
| } | ||
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| if (required()) { // ok | ||
| } | ||
| } | ||
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| function onlyErrorsWhenUnusedInBody() { | ||
| function test() { return Math.random() > 0.5; } | ||
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| if (test) { // error | ||
| ~~~~ | ||
| !!! error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| console.log('test'); | ||
| } | ||
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| if (test) { // ok | ||
| console.log(test); | ||
| } | ||
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| if (test) { // ok | ||
| test(); | ||
| } | ||
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| if (test) { // ok | ||
| [() => null].forEach(() => { | ||
| test(); | ||
| }); | ||
| } | ||
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| if (test) { // error | ||
| ~~~~ | ||
| !!! error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| [() => null].forEach(test => { | ||
| test(); | ||
| }); | ||
| } | ||
| } | ||
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| function checksPropertyAccess() { | ||
| const x = { | ||
| foo: { | ||
| bar() { return true; } | ||
| } | ||
| } | ||
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| if (x.foo.bar) { // error | ||
| ~~~~~~~~~ | ||
| !!! error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| } | ||
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| if (x.foo.bar) { // ok | ||
| x.foo.bar; | ||
| } | ||
| } | ||
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| class Foo { | ||
| maybeIsUser?: () => boolean; | ||
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| isUser() { | ||
| return true; | ||
| } | ||
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| test() { | ||
| if (this.isUser) { // error | ||
| ~~~~~~~~~~~ | ||
| !!! error TS2774: This condition will always return true since the function is always defined. Did you mean to call it instead? | ||
| } | ||
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| if (this.maybeIsUser) { // ok | ||
| } | ||
| } | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,134 @@ | ||
| //// [truthinessCallExpressionCoercion.ts] | ||
| function onlyErrorsWhenTestingNonNullableFunctionType(required: () => boolean, optional?: () => boolean) { | ||
| if (required) { // error | ||
| } | ||
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| if (optional) { // ok | ||
| } | ||
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| if (!!required) { // ok | ||
| } | ||
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| if (required()) { // ok | ||
| } | ||
| } | ||
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| function onlyErrorsWhenUnusedInBody() { | ||
| function test() { return Math.random() > 0.5; } | ||
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| if (test) { // error | ||
| console.log('test'); | ||
| } | ||
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| if (test) { // ok | ||
| console.log(test); | ||
| } | ||
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| if (test) { // ok | ||
| test(); | ||
| } | ||
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| if (test) { // ok | ||
| [() => null].forEach(() => { | ||
| test(); | ||
| }); | ||
| } | ||
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| if (test) { // error | ||
| [() => null].forEach(test => { | ||
| test(); | ||
| }); | ||
| } | ||
| } | ||
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| function checksPropertyAccess() { | ||
| const x = { | ||
| foo: { | ||
| bar() { return true; } | ||
| } | ||
| } | ||
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| if (x.foo.bar) { // error | ||
| } | ||
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| if (x.foo.bar) { // ok | ||
| x.foo.bar; | ||
| } | ||
| } | ||
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| class Foo { | ||
| maybeIsUser?: () => boolean; | ||
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| isUser() { | ||
| return true; | ||
| } | ||
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| test() { | ||
| if (this.isUser) { // error | ||
| } | ||
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| if (this.maybeIsUser) { // ok | ||
| } | ||
| } | ||
| } | ||
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| //// [truthinessCallExpressionCoercion.js] | ||
| function onlyErrorsWhenTestingNonNullableFunctionType(required, optional) { | ||
| 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 | ||
| [function () { return null; }].forEach(function () { | ||
| test(); | ||
| }); | ||
| } | ||
| if (test) { // error | ||
| [function () { return null; }].forEach(function (test) { | ||
| test(); | ||
| }); | ||
| } | ||
| } | ||
| function checksPropertyAccess() { | ||
| var x = { | ||
| foo: { | ||
| bar: function () { return true; } | ||
| } | ||
| }; | ||
| if (x.foo.bar) { // error | ||
| } | ||
| if (x.foo.bar) { // ok | ||
| x.foo.bar; | ||
| } | ||
| } | ||
| var Foo = /** @class */ (function () { | ||
| function Foo() { | ||
| } | ||
| Foo.prototype.isUser = function () { | ||
| return true; | ||
| }; | ||
| Foo.prototype.test = function () { | ||
| if (this.isUser) { // error | ||
| } | ||
| if (this.maybeIsUser) { // ok | ||
| } | ||
| }; | ||
| return Foo; | ||
| }()); |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,153 @@ | ||
| === tests/cases/compiler/truthinessCallExpressionCoercion.ts === | ||
| function onlyErrorsWhenTestingNonNullableFunctionType(required: () => boolean, optional?: () => boolean) { | ||
| >onlyErrorsWhenTestingNonNullableFunctionType : Symbol(onlyErrorsWhenTestingNonNullableFunctionType, Decl(truthinessCallExpressionCoercion.ts, 0, 0)) | ||
| >required : Symbol(required, Decl(truthinessCallExpressionCoercion.ts, 0, 54)) | ||
| >optional : Symbol(optional, Decl(truthinessCallExpressionCoercion.ts, 0, 78)) | ||
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| if (required) { // error | ||
| >required : Symbol(required, Decl(truthinessCallExpressionCoercion.ts, 0, 54)) | ||
| } | ||
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| if (optional) { // ok | ||
| >optional : Symbol(optional, Decl(truthinessCallExpressionCoercion.ts, 0, 78)) | ||
| } | ||
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| if (!!required) { // ok | ||
| >required : Symbol(required, Decl(truthinessCallExpressionCoercion.ts, 0, 54)) | ||
| } | ||
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| if (required()) { // ok | ||
| >required : Symbol(required, Decl(truthinessCallExpressionCoercion.ts, 0, 54)) | ||
| } | ||
| } | ||
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| function onlyErrorsWhenUnusedInBody() { | ||
| >onlyErrorsWhenUnusedInBody : Symbol(onlyErrorsWhenUnusedInBody, Decl(truthinessCallExpressionCoercion.ts, 12, 1)) | ||
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| function test() { return Math.random() > 0.5; } | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
| >Math.random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --)) | ||
| >Math : Symbol(Math, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --)) | ||
| >random : Symbol(Math.random, Decl(lib.es5.d.ts, --, --)) | ||
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| if (test) { // error | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
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| console.log('test'); | ||
| >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, --, --)) | ||
| } | ||
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| if (test) { // ok | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
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| console.log(test); | ||
| >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, --, --)) | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
| } | ||
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| if (test) { // ok | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
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| test(); | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
| } | ||
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| if (test) { // ok | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
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| [() => null].forEach(() => { | ||
| >[() => null].forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --)) | ||
| >forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --)) | ||
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| test(); | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
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| }); | ||
| } | ||
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| if (test) { // error | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 14, 39)) | ||
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| [() => null].forEach(test => { | ||
| >[() => null].forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --)) | ||
| >forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --)) | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 36, 29)) | ||
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| test(); | ||
| >test : Symbol(test, Decl(truthinessCallExpressionCoercion.ts, 36, 29)) | ||
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| }); | ||
| } | ||
| } | ||
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| function checksPropertyAccess() { | ||
| >checksPropertyAccess : Symbol(checksPropertyAccess, Decl(truthinessCallExpressionCoercion.ts, 40, 1)) | ||
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| const x = { | ||
| >x : Symbol(x, Decl(truthinessCallExpressionCoercion.ts, 43, 9)) | ||
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| foo: { | ||
| >foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
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| bar() { return true; } | ||
| >bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
| } | ||
| } | ||
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| if (x.foo.bar) { // error | ||
| >x.foo.bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
| >x.foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
| >x : Symbol(x, Decl(truthinessCallExpressionCoercion.ts, 43, 9)) | ||
| >foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
| >bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
| } | ||
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| if (x.foo.bar) { // ok | ||
| >x.foo.bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
| >x.foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
| >x : Symbol(x, Decl(truthinessCallExpressionCoercion.ts, 43, 9)) | ||
| >foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
| >bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
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| x.foo.bar; | ||
| >x.foo.bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
| >x.foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
| >x : Symbol(x, Decl(truthinessCallExpressionCoercion.ts, 43, 9)) | ||
| >foo : Symbol(foo, Decl(truthinessCallExpressionCoercion.ts, 43, 15)) | ||
| >bar : Symbol(bar, Decl(truthinessCallExpressionCoercion.ts, 44, 14)) | ||
| } | ||
| } | ||
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| class Foo { | ||
| >Foo : Symbol(Foo, Decl(truthinessCallExpressionCoercion.ts, 55, 1)) | ||
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| maybeIsUser?: () => boolean; | ||
| >maybeIsUser : Symbol(Foo.maybeIsUser, Decl(truthinessCallExpressionCoercion.ts, 57, 11)) | ||
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| isUser() { | ||
| >isUser : Symbol(Foo.isUser, Decl(truthinessCallExpressionCoercion.ts, 58, 32)) | ||
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| return true; | ||
| } | ||
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| test() { | ||
| >test : Symbol(Foo.test, Decl(truthinessCallExpressionCoercion.ts, 62, 5)) | ||
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| if (this.isUser) { // error | ||
| >this.isUser : Symbol(Foo.isUser, Decl(truthinessCallExpressionCoercion.ts, 58, 32)) | ||
| >this : Symbol(Foo, Decl(truthinessCallExpressionCoercion.ts, 55, 1)) | ||
| >isUser : Symbol(Foo.isUser, Decl(truthinessCallExpressionCoercion.ts, 58, 32)) | ||
| } | ||
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| if (this.maybeIsUser) { // ok | ||
| >this.maybeIsUser : Symbol(Foo.maybeIsUser, Decl(truthinessCallExpressionCoercion.ts, 57, 11)) | ||
| >this : Symbol(Foo, Decl(truthinessCallExpressionCoercion.ts, 55, 1)) | ||
| >maybeIsUser : Symbol(Foo.maybeIsUser, Decl(truthinessCallExpressionCoercion.ts, 57, 11)) | ||
| } | ||
| } | ||
| } | ||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,179 @@ | ||
| === tests/cases/compiler/truthinessCallExpressionCoercion.ts === | ||
| function onlyErrorsWhenTestingNonNullableFunctionType(required: () => boolean, optional?: () => boolean) { | ||
| >onlyErrorsWhenTestingNonNullableFunctionType : (required: () => boolean, optional?: (() => boolean) | undefined) => void | ||
| >required : () => boolean | ||
| >optional : (() => boolean) | undefined | ||
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| if (required) { // error | ||
| >required : () => boolean | ||
| } | ||
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| if (optional) { // ok | ||
| >optional : (() => boolean) | undefined | ||
| } | ||
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| if (!!required) { // ok | ||
| >!!required : true | ||
| >!required : false | ||
| >required : () => boolean | ||
| } | ||
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| if (required()) { // ok | ||
| >required() : boolean | ||
| >required : () => boolean | ||
| } | ||
| } | ||
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| function onlyErrorsWhenUnusedInBody() { | ||
| >onlyErrorsWhenUnusedInBody : () => void | ||
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| function test() { return Math.random() > 0.5; } | ||
| >test : () => boolean | ||
| >Math.random() > 0.5 : boolean | ||
| >Math.random() : number | ||
| >Math.random : () => number | ||
| >Math : Math | ||
| >random : () => number | ||
| >0.5 : 0.5 | ||
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| if (test) { // error | ||
| >test : () => boolean | ||
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| console.log('test'); | ||
| >console.log('test') : void | ||
| >console.log : (message?: any, ...optionalParams: any[]) => void | ||
| >console : Console | ||
| >log : (message?: any, ...optionalParams: any[]) => void | ||
| >'test' : "test" | ||
| } | ||
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| if (test) { // ok | ||
| >test : () => boolean | ||
|
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| console.log(test); | ||
| >console.log(test) : void | ||
| >console.log : (message?: any, ...optionalParams: any[]) => void | ||
| >console : Console | ||
| >log : (message?: any, ...optionalParams: any[]) => void | ||
| >test : () => boolean | ||
| } | ||
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| if (test) { // ok | ||
| >test : () => boolean | ||
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| test(); | ||
| >test() : boolean | ||
| >test : () => boolean | ||
| } | ||
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| if (test) { // ok | ||
| >test : () => boolean | ||
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| [() => null].forEach(() => { | ||
| >[() => null].forEach(() => { test(); }) : void | ||
| >[() => null].forEach : (callbackfn: (value: () => null, index: number, array: (() => null)[]) => void, thisArg?: any) => void | ||
| >[() => null] : (() => null)[] | ||
| >() => null : () => null | ||
| >null : null | ||
| >forEach : (callbackfn: (value: () => null, index: number, array: (() => null)[]) => void, thisArg?: any) => void | ||
| >() => { test(); } : () => void | ||
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| test(); | ||
| >test() : boolean | ||
| >test : () => boolean | ||
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| }); | ||
| } | ||
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| if (test) { // error | ||
| >test : () => boolean | ||
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| [() => null].forEach(test => { | ||
| >[() => null].forEach(test => { test(); }) : void | ||
| >[() => null].forEach : (callbackfn: (value: () => null, index: number, array: (() => null)[]) => void, thisArg?: any) => void | ||
| >[() => null] : (() => null)[] | ||
| >() => null : () => null | ||
| >null : null | ||
| >forEach : (callbackfn: (value: () => null, index: number, array: (() => null)[]) => void, thisArg?: any) => void | ||
| >test => { test(); } : (test: () => null) => void | ||
| >test : () => null | ||
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| test(); | ||
| >test() : null | ||
| >test : () => null | ||
|
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| }); | ||
| } | ||
| } | ||
|
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| function checksPropertyAccess() { | ||
| >checksPropertyAccess : () => void | ||
|
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| const x = { | ||
| >x : { foo: { bar(): boolean; }; } | ||
| >{ foo: { bar() { return true; } } } : { foo: { bar(): boolean; }; } | ||
|
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| foo: { | ||
| >foo : { bar(): boolean; } | ||
| >{ bar() { return true; } } : { bar(): boolean; } | ||
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| bar() { return true; } | ||
| >bar : () => boolean | ||
| >true : true | ||
| } | ||
| } | ||
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| if (x.foo.bar) { // error | ||
| >x.foo.bar : () => boolean | ||
| >x.foo : { bar(): boolean; } | ||
| >x : { foo: { bar(): boolean; }; } | ||
| >foo : { bar(): boolean; } | ||
| >bar : () => boolean | ||
| } | ||
|
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| if (x.foo.bar) { // ok | ||
| >x.foo.bar : () => boolean | ||
| >x.foo : { bar(): boolean; } | ||
| >x : { foo: { bar(): boolean; }; } | ||
| >foo : { bar(): boolean; } | ||
| >bar : () => boolean | ||
|
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| x.foo.bar; | ||
| >x.foo.bar : () => boolean | ||
| >x.foo : { bar(): boolean; } | ||
| >x : { foo: { bar(): boolean; }; } | ||
| >foo : { bar(): boolean; } | ||
| >bar : () => boolean | ||
| } | ||
| } | ||
|
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| class Foo { | ||
| >Foo : Foo | ||
|
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| maybeIsUser?: () => boolean; | ||
| >maybeIsUser : (() => boolean) | undefined | ||
|
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| isUser() { | ||
| >isUser : () => boolean | ||
|
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| return true; | ||
| >true : true | ||
| } | ||
|
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| test() { | ||
| >test : () => void | ||
|
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| if (this.isUser) { // error | ||
| >this.isUser : () => boolean | ||
| >this : this | ||
| >isUser : () => boolean | ||
| } | ||
|
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| if (this.maybeIsUser) { // ok | ||
| >this.maybeIsUser : (() => boolean) | undefined | ||
| >this : this | ||
| >maybeIsUser : (() => boolean) | undefined | ||
| } | ||
| } | ||
| } | ||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,74 @@ | ||
| // @strictNullChecks:true | ||
|
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| 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 | ||
| } | ||
| } | ||
| } |
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This is a pretty good example of what TS would now consider suspicious-enough code to error on. Making
eoptional would also have fixed this.