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Issue unawaited promise error on symbol-less expressions #44491

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merged 3 commits into from
Jun 28, 2021
Merged

Issue unawaited promise error on symbol-less expressions #44491

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2522469
Issue unawaited promise error on symbol-less expressions
andrewbranch Jun 7, 2021
60d5813
Use same behavior for call expressions
andrewbranch Jun 24, 2021
e305ac3
Revert "Use same behavior for call expressions"
andrewbranch Jun 25, 2021
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17 changes: 8 additions & 9 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -35699,15 +35699,14 @@ namespace ts {
if (getFalsyFlags(type)) return;

const location = isBinaryExpression(condExpr) ? condExpr.right : condExpr;
if (isPropertyAccessExpression(location) && isAssertionExpression(skipParentheses(location.expression))) {
return;
}

const testedNode = isIdentifier(location) ? location
: isPropertyAccessExpression(location) ? location.name
: isBinaryExpression(location) && isIdentifier(location.right) ? location.right
: undefined;
const isPropertyExpressionCast = isPropertyAccessExpression(location)
&& isAssertionExpression(skipParentheses(location.expression));
if (!testedNode || isPropertyExpressionCast) {
return;
}

// While it technically should be invalid for any known-truthy value
// to be tested, we de-scope to functions and Promises unreferenced in
Expand All @@ -35720,13 +35719,13 @@ namespace ts {
return;
}

const testedSymbol = getSymbolAtLocation(testedNode);
if (!testedSymbol) {
const testedSymbol = testedNode && getSymbolAtLocation(testedNode);
if (!testedSymbol && !isPromise) {
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I don’t know that we actually need have divergent behavior for unawaited promises and uncalled expressions here—what do we expect for something like

const or = x => y => x || y;

if (or(true)) { // today: no error, but maybe should be?
  // ...
}

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Expanding it to uncalled functions seems like an improvement to me. We just need to know that it won't break lots of existing code. Are you up for checking DT and RWC to see?

return;
}

const isUsed = isBinaryExpression(condExpr.parent) && isSymbolUsedInBinaryExpressionChain(condExpr.parent, testedSymbol)
|| body && isSymbolUsedInConditionBody(condExpr, body, testedNode, testedSymbol);
const isUsed = testedSymbol && isBinaryExpression(condExpr.parent) && isSymbolUsedInBinaryExpressionChain(condExpr.parent, testedSymbol)
|| testedSymbol && body && isSymbolUsedInConditionBody(condExpr, body, testedNode!, testedSymbol);
if (!isUsed) {
if (isPromise) {
errorAndMaybeSuggestAwait(
Expand Down
33 changes: 26 additions & 7 deletions tests/baselines/reference/truthinessPromiseCoercion.errors.txt
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@@ -1,25 +1,28 @@
tests/cases/compiler/truthinessPromiseCoercion.ts(6,9): error TS2801: This condition will always return true since this 'Promise<number>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(10,5): error TS2801: This condition will always return true since this 'Promise<number>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(31,9): error TS2801: This condition will always return true since this 'Promise<unknown>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(7,9): error TS2801: This condition will always return true since this 'Promise<number>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(11,5): error TS2801: This condition will always return true since this 'Promise<number>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(32,9): error TS2801: This condition will always return true since this 'Promise<unknown>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(40,9): error TS2801: This condition will always return true since this 'Promise<boolean>' is always defined.
tests/cases/compiler/truthinessPromiseCoercion.ts(43,9): error TS2801: This condition will always return true since this 'Promise<boolean>' is always defined.


==== tests/cases/compiler/truthinessPromiseCoercion.ts (3 errors) ====
==== tests/cases/compiler/truthinessPromiseCoercion.ts (5 errors) ====
declare const p: Promise<number>
declare const p2: null | Promise<number>
declare const obj: { p: Promise<unknown> }
declare function pf(): Promise<boolean>

async function f() {
if (p) {} // err
~
!!! error TS2801: This condition will always return true since this 'Promise<number>' is always defined.
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:6:9: Did you forget to use 'await'?
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:7:9: Did you forget to use 'await'?
if (!!p) {} // no err
if (p2) {} // no err

p ? f.arguments : f.arguments;
~
!!! error TS2801: This condition will always return true since this 'Promise<number>' is always defined.
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:10:5: Did you forget to use 'await'?
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:11:5: Did you forget to use 'await'?
!!p ? f.arguments : f.arguments;
p2 ? f.arguments : f.arguments;
}
Expand All @@ -43,10 +46,26 @@ tests/cases/compiler/truthinessPromiseCoercion.ts(31,9): error TS2801: This cond
if (obj.p) {} // error
~~~~~
!!! error TS2801: This condition will always return true since this 'Promise<unknown>' is always defined.
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:31:9: Did you forget to use 'await'?
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:32:9: Did you forget to use 'await'?
if (obj.p) { // ok
await obj.p;
}
if (obj.p && await obj.p) {} // ok
}

async function i(): Promise<string> {
if (pf()) { // error
~~~~
!!! error TS2801: This condition will always return true since this 'Promise<boolean>' is always defined.
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:40:9: Did you forget to use 'await'?
return "true";
}
if (pf()) { // error
~~~~
!!! error TS2801: This condition will always return true since this 'Promise<boolean>' is always defined.
!!! related TS2773 tests/cases/compiler/truthinessPromiseCoercion.ts:43:9: Did you forget to use 'await'?
pf().then();
}
return "false";
}

20 changes: 20 additions & 0 deletions tests/baselines/reference/truthinessPromiseCoercion.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
declare const p: Promise<number>
declare const p2: null | Promise<number>
declare const obj: { p: Promise<unknown> }
declare function pf(): Promise<boolean>

async function f() {
if (p) {} // err
Expand Down Expand Up @@ -35,6 +36,16 @@ async function h() {
}
if (obj.p && await obj.p) {} // ok
}

async function i(): Promise<string> {
if (pf()) { // error
return "true";
}
if (pf()) { // error
pf().then();
}
return "false";
}


//// [truthinessPromiseCoercion.js]
Expand Down Expand Up @@ -67,3 +78,12 @@ async function h() {
}
if (obj.p && await obj.p) { } // ok
}
async function i() {
if (pf()) { // error
return "true";
}
if (pf()) { // error
pf().then();
}
return "false";
}
42 changes: 33 additions & 9 deletions tests/baselines/reference/truthinessPromiseCoercion.symbols
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Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,12 @@ declare const obj: { p: Promise<unknown> }
>p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 2, 20))
>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2018.promise.d.ts, --, --))

declare function pf(): Promise<boolean>
>pf : Symbol(pf, Decl(truthinessPromiseCoercion.ts, 2, 42))
>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2018.promise.d.ts, --, --))

async function f() {
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))

if (p) {} // err
>p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 0, 13))
Expand All @@ -27,34 +31,34 @@ async function f() {
p ? f.arguments : f.arguments;
>p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 0, 13))
>f.arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))
>arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f.arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))
>arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))

!!p ? f.arguments : f.arguments;
>p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 0, 13))
>f.arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))
>arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f.arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))
>arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))

p2 ? f.arguments : f.arguments;
>p2 : Symbol(p2, Decl(truthinessPromiseCoercion.ts, 1, 13))
>f.arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))
>arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f.arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 2, 42))
>f : Symbol(f, Decl(truthinessPromiseCoercion.ts, 3, 39))
>arguments : Symbol(Function.arguments, Decl(lib.es5.d.ts, --, --))
}

// all ok
async function g() {
>g : Symbol(g, Decl(truthinessPromiseCoercion.ts, 12, 1))
>g : Symbol(g, Decl(truthinessPromiseCoercion.ts, 13, 1))

if (p) {
>p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 0, 13))
Expand Down Expand Up @@ -87,7 +91,7 @@ async function g() {
}

async function h() {
>h : Symbol(h, Decl(truthinessPromiseCoercion.ts, 27, 1))
>h : Symbol(h, Decl(truthinessPromiseCoercion.ts, 28, 1))

if (obj.p) {} // error
>obj.p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 2, 20))
Expand All @@ -113,3 +117,23 @@ async function h() {
>p : Symbol(p, Decl(truthinessPromiseCoercion.ts, 2, 20))
}

async function i(): Promise<string> {
>i : Symbol(i, Decl(truthinessPromiseCoercion.ts, 36, 1))
>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2018.promise.d.ts, --, --))

if (pf()) { // error
>pf : Symbol(pf, Decl(truthinessPromiseCoercion.ts, 2, 42))

return "true";
}
if (pf()) { // error
>pf : Symbol(pf, Decl(truthinessPromiseCoercion.ts, 2, 42))

pf().then();
>pf().then : Symbol(Promise.then, Decl(lib.es5.d.ts, --, --))
>pf : Symbol(pf, Decl(truthinessPromiseCoercion.ts, 2, 42))
>then : Symbol(Promise.then, Decl(lib.es5.d.ts, --, --))
}
return "false";
}

28 changes: 28 additions & 0 deletions tests/baselines/reference/truthinessPromiseCoercion.types
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,9 @@ declare const obj: { p: Promise<unknown> }
>obj : { p: Promise<unknown>; }
>p : Promise<unknown>

declare function pf(): Promise<boolean>
>pf : () => Promise<boolean>

async function f() {
>f : () => Promise<void>

Expand Down Expand Up @@ -132,3 +135,28 @@ async function h() {
>p : Promise<unknown>
}

async function i(): Promise<string> {
>i : () => Promise<string>

if (pf()) { // error
>pf() : Promise<boolean>
>pf : () => Promise<boolean>

return "true";
>"true" : "true"
}
if (pf()) { // error
>pf() : Promise<boolean>
>pf : () => Promise<boolean>

pf().then();
>pf().then() : Promise<boolean>
>pf().then : <TResult1 = boolean, TResult2 = never>(onfulfilled?: ((value: boolean) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null | undefined) => Promise<TResult1 | TResult2>
>pf() : Promise<boolean>
>pf : () => Promise<boolean>
>then : <TResult1 = boolean, TResult2 = never>(onfulfilled?: ((value: boolean) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null | undefined) => Promise<TResult1 | TResult2>
}
return "false";
>"false" : "false"
}

11 changes: 11 additions & 0 deletions tests/cases/compiler/truthinessPromiseCoercion.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
declare const p: Promise<number>
declare const p2: null | Promise<number>
declare const obj: { p: Promise<unknown> }
declare function pf(): Promise<boolean>

async function f() {
if (p) {} // err
Expand Down Expand Up @@ -37,3 +38,13 @@ async function h() {
}
if (obj.p && await obj.p) {} // ok
}

async function i(): Promise<string> {
if (pf()) { // error
return "true";
}
if (pf()) { // error
pf().then();
}
return "false";
}