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Merged
merged 6 commits into from
Oct 18, 2016
Merged

Contextual typing of partially annotated signatures #11673

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8094b2c
Improve contextual typing of partially annotated signatures
ahejlsberg Oct 17, 2016
808db07
Accept new baselines
ahejlsberg Oct 17, 2016
6425f0c
Fix lint error
ahejlsberg Oct 17, 2016
df58df1
Add partially annotated function tests
HerringtonDarkholme Oct 17, 2016
8aa56c1
Add fourslash test for contextually-typed `this`
sandersn Oct 17, 2016
af52b63
Address CR feedback
ahejlsberg Oct 17, 2016
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66 changes: 47 additions & 19 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3144,8 +3144,7 @@ namespace ts {
// Use contextual parameter type if one is available
let type: Type;
if (declaration.symbol.name === "this") {
const thisParameter = getContextualThisParameter(func);
type = thisParameter ? getTypeOfSymbol(thisParameter) : undefined;
type = getContextualThisParameterType(func);
}
else {
type = getContextuallyTypedParameterType(<ParameterDeclaration>declaration);
Expand Down Expand Up @@ -4789,9 +4788,6 @@ namespace ts {
if (isJSConstructSignature) {
minArgumentCount--;
}
if (!thisParameter && isObjectLiteralMethod(declaration)) {
thisParameter = getContextualThisParameter(declaration);
}

const classType = declaration.kind === SyntaxKind.Constructor ?
getDeclaredTypeOfClassOrInterface(getMergedSymbol((<ClassDeclaration>declaration.parent).symbol))
Expand Down Expand Up @@ -6101,9 +6097,24 @@ namespace ts {
}

function isContextSensitiveFunctionLikeDeclaration(node: FunctionLikeDeclaration) {
const areAllParametersUntyped = !forEach(node.parameters, p => p.type);
const isNullaryArrow = node.kind === SyntaxKind.ArrowFunction && !node.parameters.length;
return !node.typeParameters && areAllParametersUntyped && !isNullaryArrow;
// Functions with type parameters are not context sensitive.
if (node.typeParameters) {
return false;
}
// Functions with any parameters that lack type annotations are context sensitive.
if (forEach(node.parameters, p => !p.type)) {
return true;
}
// For arrow functions we now know we're not context sensitive.
if (node.kind === SyntaxKind.ArrowFunction) {
return false;
}
// If the first parameter is not an explicit 'this' parameter, then the function has
// an implicit 'this' parameter which is subject to contextual typing. Otherwise we
// know that all parameters (including 'this') have type annotations and nothing is
// subject to contextual typing.
const parameter = firstOrUndefined(node.parameters);
return !(parameter && parameterIsThisKeyword(parameter));
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This can be written as !parameterIsThisKeyword(firstOrUndefined(node.parameters))

}

function isContextSensitiveFunctionOrObjectLiteralMethod(func: Node): func is FunctionExpression | ArrowFunction | MethodDeclaration {
Expand Down Expand Up @@ -9629,7 +9640,7 @@ namespace ts {
}
}

const thisType = getThisTypeOfDeclaration(container);
const thisType = getThisTypeOfDeclaration(container) || getContextualThisParameterType(container);
if (thisType) {
return thisType;
}
Expand Down Expand Up @@ -9869,14 +9880,16 @@ namespace ts {
}
}

function getContextualThisParameter(func: FunctionLikeDeclaration): Symbol {
function getContextualThisParameterType(func: FunctionLikeDeclaration): Type {
if (isContextSensitiveFunctionOrObjectLiteralMethod(func) && func.kind !== SyntaxKind.ArrowFunction) {
const contextualSignature = getContextualSignature(func);
if (contextualSignature) {
return contextualSignature.thisParameter;
const thisParameter = contextualSignature.thisParameter;
if (thisParameter) {
return getTypeOfSymbol(thisParameter);
}
}
}

return undefined;
}

Expand Down Expand Up @@ -12840,21 +12853,36 @@ namespace ts {

function assignContextualParameterTypes(signature: Signature, context: Signature, mapper: TypeMapper) {
const len = signature.parameters.length - (signature.hasRestParameter ? 1 : 0);
if (isInferentialContext(mapper)) {
for (let i = 0; i < len; i++) {
const declaration = <ParameterDeclaration>signature.parameters[i].valueDeclaration;
if (declaration.type) {
inferTypes(mapper.context, getTypeFromTypeNode(declaration.type), getTypeAtPosition(context, i));
}
}
}
if (context.thisParameter) {
if (!signature.thisParameter) {
signature.thisParameter = createTransientSymbol(context.thisParameter, undefined);
const parameter = signature.thisParameter;
if (!parameter || parameter.valueDeclaration && !(<ParameterDeclaration>parameter.valueDeclaration).type) {
if (!parameter) {
signature.thisParameter = createTransientSymbol(context.thisParameter, undefined);
}
assignTypeToParameterAndFixTypeParameters(signature.thisParameter, getTypeOfSymbol(context.thisParameter), mapper);
}
assignTypeToParameterAndFixTypeParameters(signature.thisParameter, getTypeOfSymbol(context.thisParameter), mapper);
}
for (let i = 0; i < len; i++) {
const parameter = signature.parameters[i];
const contextualParameterType = getTypeAtPosition(context, i);
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
if (!(<ParameterDeclaration>parameter.valueDeclaration).type) {
const contextualParameterType = getTypeAtPosition(context, i);
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
}
}
if (signature.hasRestParameter && isRestParameterIndex(context, signature.parameters.length - 1)) {
const parameter = lastOrUndefined(signature.parameters);
const contextualParameterType = getTypeOfSymbol(lastOrUndefined(context.parameters));
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
if (!(<ParameterDeclaration>parameter.valueDeclaration).type) {
const contextualParameterType = getTypeOfSymbol(lastOrUndefined(context.parameters));
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType, mapper);
}
}
}

Expand Down
27 changes: 27 additions & 0 deletions tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.errors.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(12,11): error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(13,11): error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts(14,11): error TS2345: Argument of type '(t1: C, t2: C, t3: D) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.


==== tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceError.ts (3 errors) ====
class C {
test: string
}

class D extends C {
test2: string
}

declare function testError<T extends C>(a: (t: T, t1: T) => void): T

// more args
testError((t1: D, t2, t3) => {})
~~~~~~~~~~~~~~~~~~~~~
!!! error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
testError((t1, t2: D, t3) => {})
~~~~~~~~~~~~~~~~~~~~~
!!! error TS2345: Argument of type '(t1: D, t2: D, t3: any) => void' is not assignable to parameter of type '(t: D, t1: D) => void'.
testError((t1, t2, t3: D) => {})
~~~~~~~~~~~~~~~~~~~~~
!!! error TS2345: Argument of type '(t1: C, t2: C, t3: D) => void' is not assignable to parameter of type '(t: C, t1: C) => void'.

39 changes: 39 additions & 0 deletions tests/baselines/reference/partiallyAnnotatedFunctionInferenceError.js
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@@ -0,0 +1,39 @@
//// [partiallyAnnotatedFunctionInferenceError.ts]
class C {
test: string
}

class D extends C {
test2: string
}

declare function testError<T extends C>(a: (t: T, t1: T) => void): T

// more args
testError((t1: D, t2, t3) => {})
testError((t1, t2: D, t3) => {})
testError((t1, t2, t3: D) => {})


//// [partiallyAnnotatedFunctionInferenceError.js]
var __extends = (this && this.__extends) || function (d, b) {
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var C = (function () {
function C() {
}
return C;
}());
var D = (function (_super) {
__extends(D, _super);
function D() {
return _super.apply(this, arguments) || this;
}
return D;
}(C));
// more args
testError(function (t1, t2, t3) { });
testError(function (t1, t2, t3) { });
testError(function (t1, t2, t3) { });
85 changes: 85 additions & 0 deletions tests/baselines/reference/partiallyAnnotatedFunctionInferenceWithTypeParameter.js
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@@ -0,0 +1,85 @@
//// [partiallyAnnotatedFunctionInferenceWithTypeParameter.ts]
class C {
test: string
}

class D extends C {
test2: string
}

declare function test<T extends C>(a: (t: T, t1: T) => void): T

declare function testRest<T extends C>(a: (t: T, t1: T, ...ts: T[]) => void): T


// exactly
test((t1: D, t2) => { t2.test2 })
test((t1, t2: D) => { t2.test2 })

// zero arg
test(() => {})

// fewer args
test((t1: D) => {})

// rest arg
test((...ts: D[]) => {})

// source function has rest arg
testRest((t1: D) => {})
testRest((t1, t2, t3) => {})
testRest((t1: D, t2, t3) => {})
testRest((t1, t2: D, t3) => {})
testRest((t2: D, ...t3) => {})
testRest((t2, ...t3: D[]) => {})


//// [partiallyAnnotatedFunctionInferenceWithTypeParameter.js]
var __extends = (this && this.__extends) || function (d, b) {
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var C = (function () {
function C() {
}
return C;
}());
var D = (function (_super) {
__extends(D, _super);
function D() {
return _super.apply(this, arguments) || this;
}
return D;
}(C));
// exactly
test(function (t1, t2) { t2.test2; });
test(function (t1, t2) { t2.test2; });
// zero arg
test(function () { });
// fewer args
test(function (t1) { });
// rest arg
test(function () {
var ts = [];
for (var _i = 0; _i < arguments.length; _i++) {
ts[_i - 0] = arguments[_i];
}
});
// source function has rest arg
testRest(function (t1) { });
testRest(function (t1, t2, t3) { });
testRest(function (t1, t2, t3) { });
testRest(function (t1, t2, t3) { });
testRest(function (t2) {
var t3 = [];
for (var _i = 1; _i < arguments.length; _i++) {
t3[_i - 1] = arguments[_i];
}
});
testRest(function (t2) {
var t3 = [];
for (var _i = 1; _i < arguments.length; _i++) {
t3[_i - 1] = arguments[_i];
}
});
114 changes: 114 additions & 0 deletions tests/baselines/reference/partiallyAnnotatedFunctionInferenceWithTypeParameter.symbols
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@@ -0,0 +1,114 @@
=== tests/cases/conformance/types/contextualTypes/partiallyAnnotatedFunction/partiallyAnnotatedFunctionInferenceWithTypeParameter.ts ===
class C {
>C : Symbol(C, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 0, 0))

test: string
>test : Symbol(C.test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 0, 9))
}

class D extends C {
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))
>C : Symbol(C, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 0, 0))

test2: string
>test2 : Symbol(D.test2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 4, 19))
}

declare function test<T extends C>(a: (t: T, t1: T) => void): T
>test : Symbol(test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 6, 1))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 22))
>C : Symbol(C, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 0, 0))
>a : Symbol(a, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 35))
>t : Symbol(t, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 39))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 22))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 44))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 22))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 22))

declare function testRest<T extends C>(a: (t: T, t1: T, ...ts: T[]) => void): T
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 26))
>C : Symbol(C, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 0, 0))
>a : Symbol(a, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 39))
>t : Symbol(t, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 43))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 26))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 48))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 26))
>ts : Symbol(ts, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 55))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 26))
>T : Symbol(T, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 10, 26))


// exactly
test((t1: D, t2) => { t2.test2 })
>test : Symbol(test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 6, 1))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 14, 6))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 14, 12))
>t2.test2 : Symbol(D.test2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 4, 19))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 14, 12))
>test2 : Symbol(D.test2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 4, 19))

test((t1, t2: D) => { t2.test2 })
>test : Symbol(test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 6, 1))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 15, 6))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 15, 9))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))
>t2.test2 : Symbol(D.test2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 4, 19))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 15, 9))
>test2 : Symbol(D.test2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 4, 19))

// zero arg
test(() => {})
>test : Symbol(test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 6, 1))

// fewer args
test((t1: D) => {})
>test : Symbol(test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 6, 1))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 21, 6))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))

// rest arg
test((...ts: D[]) => {})
>test : Symbol(test, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 6, 1))
>ts : Symbol(ts, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 24, 6))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))

// source function has rest arg
testRest((t1: D) => {})
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 27, 10))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))

testRest((t1, t2, t3) => {})
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 28, 10))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 28, 13))
>t3 : Symbol(t3, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 28, 17))

testRest((t1: D, t2, t3) => {})
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 29, 10))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 29, 16))
>t3 : Symbol(t3, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 29, 20))

testRest((t1, t2: D, t3) => {})
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>t1 : Symbol(t1, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 30, 10))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 30, 13))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))
>t3 : Symbol(t3, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 30, 20))

testRest((t2: D, ...t3) => {})
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 31, 10))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))
>t3 : Symbol(t3, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 31, 16))

testRest((t2, ...t3: D[]) => {})
>testRest : Symbol(testRest, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 8, 63))
>t2 : Symbol(t2, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 32, 10))
>t3 : Symbol(t3, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 32, 13))
>D : Symbol(D, Decl(partiallyAnnotatedFunctionInferenceWithTypeParameter.ts, 2, 1))

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