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Don't mention all the possible return types that permit no return statements #53560

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f87871d
Don't list every type in the world in the error message.
DanielRosenwasser Mar 27, 2023
82650b8
Accepted baselines.
DanielRosenwasser Mar 27, 2023
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9 changes: 2 additions & 7 deletions src/compiler/checker.ts
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Expand Up @@ -35664,7 +35664,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
const functionFlags = getFunctionFlags(func);
const type = returnType && unwrapReturnType(returnType, functionFlags);

// Functions with an explicitly specified 'undefined, 'void', 'any' or 'unknown' return type don't need any return expressions.
// Functions with an explicitly specified 'undefined, 'void', 'any', or 'unknown' return type don't need any return expressions.
if (type && maybeTypeOfKind(type, TypeFlags.Undefined | TypeFlags.Void | TypeFlags.Any | TypeFlags.Unknown)) {
return;
}
Expand All @@ -35684,12 +35684,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
else if (type && !hasExplicitReturn) {
// minimal check: function has syntactic return type annotation and no explicit return statements in the body
// this function does not conform to the specification.
if (strictNullChecks) {
error(errorNode, Diagnostics.A_function_whose_declared_type_is_neither_undefined_void_nor_any_must_return_a_value);
}
else {
error(errorNode, Diagnostics.A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value);
}
error(errorNode, Diagnostics.A_function_with_this_return_type_needs_to_explicitly_return_a_value);
}
else if (type && strictNullChecks) {
error(errorNode, Diagnostics.Function_lacks_ending_return_statement_and_return_type_does_not_include_undefined);
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6 changes: 1 addition & 5 deletions src/compiler/diagnosticMessages.json
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Expand Up @@ -1880,10 +1880,6 @@
"category": "Error",
"code": 2354
},
"A function whose declared type is neither 'void' nor 'any' must return a value.": {
"category": "Error",
"code": 2355
},
"An arithmetic operand must be of type 'any', 'number', 'bigint' or an enum type.": {
"category": "Error",
"code": 2356
Expand Down Expand Up @@ -3619,7 +3615,7 @@
"category": "Error",
"code": 2846
},
"A function whose declared type is neither 'undefined', 'void', nor 'any' must return a value.": {
"A function with this return type needs to explicitly return a value.": {
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"must explicitly"? (Not sure what form we use most often)

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Let's pretend we're starting from scratch. What would you prefer to see as a user?

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I like this diagnostic, but I might be a bit confused when the return type is inferred. That's unrelated to the message per se though.

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Can we do something like A function with return type 'X' needs to explicitly return a value.? I think this would help with Maria's point about when the return type is inferred.

"category": "Error",
"code": 2847
},
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6 changes: 2 additions & 4 deletions src/services/codefixes/returnValueCorrect.ts
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Expand Up @@ -51,8 +51,7 @@ const fixIdAddReturnStatement = "fixAddReturnStatement";
const fixRemoveBracesFromArrowFunctionBody = "fixRemoveBracesFromArrowFunctionBody";
const fixIdWrapTheBlockWithParen = "fixWrapTheBlockWithParen";
const errorCodes = [
Diagnostics.A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value.code,
Diagnostics.A_function_whose_declared_type_is_neither_undefined_void_nor_any_must_return_a_value.code,
Diagnostics.A_function_with_this_return_type_needs_to_explicitly_return_a_value.code,
Diagnostics.Type_0_is_not_assignable_to_type_1.code,
Diagnostics.Argument_of_type_0_is_not_assignable_to_parameter_of_type_1.code
];
Expand Down Expand Up @@ -214,8 +213,7 @@ function getInfo(checker: TypeChecker, sourceFile: SourceFile, position: number,

const declaration = findAncestor(node.parent, isFunctionLikeDeclaration);
switch (errorCode) {
case Diagnostics.A_function_whose_declared_type_is_neither_void_nor_any_must_return_a_value.code:
case Diagnostics.A_function_whose_declared_type_is_neither_undefined_void_nor_any_must_return_a_value.code:
case Diagnostics.A_function_with_this_return_type_needs_to_explicitly_return_a_value.code:
if (!declaration || !declaration.body || !declaration.type || !rangeContainsRange(declaration.type, node)) return undefined;
return getFixInfo(checker, declaration, checker.getTypeFromTypeNode(declaration.type), /*isFunctionType*/ false);
case Diagnostics.Argument_of_type_0_is_not_assignable_to_parameter_of_type_1.code:
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4 changes: 2 additions & 2 deletions tests/baselines/reference/ParameterList5.errors.txt
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@@ -1,12 +1,12 @@
tests/cases/compiler/ParameterList5.ts(1,15): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/compiler/ParameterList5.ts(1,15): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/compiler/ParameterList5.ts(1,16): error TS2369: A parameter property is only allowed in a constructor implementation.
tests/cases/compiler/ParameterList5.ts(1,29): error TS2304: Cannot find name 'C'.


==== tests/cases/compiler/ParameterList5.ts (3 errors) ====
function A(): (public B) => C {
~~~~~~~~~~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
~~~~~~~~
!!! error TS2369: A parameter property is only allowed in a constructor implementation.
~
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8 changes: 4 additions & 4 deletions tests/baselines/reference/asyncFunctionDeclaration15_es5.errors.txt
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@@ -1,8 +1,8 @@
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS1055: Type '{}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(6,23): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(7,23): error TS1055: Type 'any' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS1055: Type 'number' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(8,23): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(9,23): error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration15_es5.ts(10,23): error TS1055: Type 'typeof Thenable' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
Construct signature return types 'Thenable' and 'PromiseLike<T>' are incompatible.
Expand All @@ -22,15 +22,15 @@ tests/cases/conformance/async/es5/functionDeclarations/asyncFunctionDeclaration1
~~~
!!! error TS1055: Type '{}' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
async function fn3(): any { } // error
~~~
!!! error TS1055: Type 'any' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
async function fn4(): number { } // error
~~~~~~
!!! error TS1055: Type 'number' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
async function fn5(): PromiseLike<void> { } // error
~~~~~~~~~~~~~~~~~
!!! error TS1055: Type 'PromiseLike' is not a valid async function return type in ES5/ES3 because it does not refer to a Promise-compatible constructor value.
Expand Down
8 changes: 4 additions & 4 deletions tests/baselines/reference/asyncFunctionDeclaration15_es6.errors.txt
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@@ -1,8 +1,8 @@
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(6,23): error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<{}>'?
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(6,23): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(6,23): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(7,23): error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<any>'?
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(8,23): error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<number>'?
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(8,23): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(8,23): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(9,23): error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<void>'?
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(10,23): error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<void>'?
tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration15_es6.ts(17,16): error TS1058: The return type of an async function must either be a valid promise or must not contain a callable 'then' member.
Expand All @@ -19,15 +19,15 @@ tests/cases/conformance/async/es6/functionDeclarations/asyncFunctionDeclaration1
~~~
!!! error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<{}>'?
~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
async function fn3(): any { } // error
~~~
!!! error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<any>'?
async function fn4(): number { } // error
~~~~~~
!!! error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<number>'?
~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
async function fn5(): PromiseLike<void> { } // error
~~~~~~~~~~~~~~~~~
!!! error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<void>'?
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8 changes: 4 additions & 4 deletions tests/baselines/reference/conflictingTypeAnnotatedVar.errors.txt
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@@ -1,10 +1,10 @@
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(1,5): error TS2300: Duplicate identifier 'foo'.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(2,10): error TS2300: Duplicate identifier 'foo'.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(2,10): error TS2393: Duplicate function implementation.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(2,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(2,17): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,10): error TS2300: Duplicate identifier 'foo'.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,10): error TS2393: Duplicate function implementation.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,17): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,17): error TS2847: A function with this return type needs to explicitly return a value.


==== tests/cases/compiler/conflictingTypeAnnotatedVar.ts (7 errors) ====
Expand All @@ -17,11 +17,11 @@ tests/cases/compiler/conflictingTypeAnnotatedVar.ts(3,17): error TS2355: A funct
~~~
!!! error TS2393: Duplicate function implementation.
~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
function foo(): number { }
~~~
!!! error TS2300: Duplicate identifier 'foo'.
~~~
!!! error TS2393: Duplicate function implementation.
~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
4 changes: 2 additions & 2 deletions tests/baselines/reference/controlFlowGenericTypes.errors.txt
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Expand Up @@ -2,7 +2,7 @@ tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(49,15): error TS2
tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(55,15): error TS2345: Argument of type 'undefined' is not assignable to parameter of type 'Box<unknown>'.
tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(81,11): error TS2339: Property 'foo' does not exist on type 'MyUnion'.
Property 'foo' does not exist on type 'AA'.
tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(90,44): error TS2847: A function whose declared type is neither 'undefined', 'void', nor 'any' must return a value.
tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(90,44): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(91,11): error TS2339: Property 'foo' does not exist on type 'MyUnion'.
Property 'foo' does not exist on type 'AA'.
tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(156,16): error TS18048: 'obj' is possibly 'undefined'.
Expand Down Expand Up @@ -109,7 +109,7 @@ tests/cases/conformance/controlFlow/controlFlowGenericTypes.ts(168,9): error TS1

const fn2 = <T extends MyUnion>(value: T): MyUnion => {
~~~~~~~
!!! error TS2847: A function whose declared type is neither 'undefined', 'void', nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
value.foo; // Error
~~~
!!! error TS2339: Property 'foo' does not exist on type 'MyUnion'.
Expand Down
4 changes: 2 additions & 2 deletions tests/baselines/reference/errorOnContextuallyTypedReturnType.errors.txt
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@@ -1,6 +1,6 @@
tests/cases/compiler/errorOnContextuallyTypedReturnType.ts(1,5): error TS2322: Type '() => void' is not assignable to type '() => boolean'.
Type 'void' is not assignable to type 'boolean'.
tests/cases/compiler/errorOnContextuallyTypedReturnType.ts(2,37): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/compiler/errorOnContextuallyTypedReturnType.ts(2,37): error TS2847: A function with this return type needs to explicitly return a value.


==== tests/cases/compiler/errorOnContextuallyTypedReturnType.ts (2 errors) ====
Expand All @@ -10,5 +10,5 @@ tests/cases/compiler/errorOnContextuallyTypedReturnType.ts(2,37): error TS2355:
!!! error TS2322: Type 'void' is not assignable to type 'boolean'.
var n2: () => boolean = function ():boolean { }; // expect an error here
~~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.

12 changes: 6 additions & 6 deletions tests/baselines/reference/errorOnFunctionReturnType.errors.txt
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@@ -1,7 +1,7 @@
tests/cases/conformance/jsdoc/foo.js(7,10): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/jsdoc/foo.js(7,10): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/jsdoc/foo.js(13,5): error TS2322: Type 'string' is not assignable to type 'number'.
tests/cases/conformance/jsdoc/foo.js(16,60): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/jsdoc/foo.js(21,20): error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
tests/cases/conformance/jsdoc/foo.js(16,60): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/jsdoc/foo.js(21,20): error TS2847: A function with this return type needs to explicitly return a value.
tests/cases/conformance/jsdoc/foo.js(31,10): error TS2534: A function returning 'never' cannot have a reachable end point.
tests/cases/conformance/jsdoc/foo.js(37,5): error TS2322: Type 'string' is not assignable to type 'never'.
tests/cases/conformance/jsdoc/foo.js(40,56): error TS2534: A function returning 'never' cannot have a reachable end point.
Expand All @@ -17,7 +17,7 @@ tests/cases/conformance/jsdoc/foo.js(45,18): error TS2534: A function returning
/** @type {FunctionReturningPromise} */
function testPromise1() {
~~~~~~~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
console.log("Nope");
}

Expand All @@ -30,14 +30,14 @@ tests/cases/conformance/jsdoc/foo.js(45,18): error TS2534: A function returning

var testPromise3 = /** @type {FunctionReturningPromise} */ function() {
~~~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
console.log("test")
}

/** @type {FunctionReturningPromise} */
var testPromise4 = function() {
~~~~~~~~
!!! error TS2355: A function whose declared type is neither 'void' nor 'any' must return a value.
!!! error TS2847: A function with this return type needs to explicitly return a value.
console.log("test")
}

Expand Down
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