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Merge pull request #19838 from Microsoft/narrow-index-signature-property-access

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Narrow property access of undeclared properties from string index signatures
This commit is contained in:
Nathan Shively-Sanders 2017-11-08 12:10:52 -08:00 committed by GitHub
parent ca181a7952 2548aced3f
commit 76a3be7c4c
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 120 additions and 9 deletions
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23
src/compiler/checker.ts
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@ -15221,7 +15221,7 @@ namespace ts {
if (indexInfo.isReadonly && (isAssignmentTarget(node) || isDeleteTarget(node))) {
error(node, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(apparentType));
}
return indexInfo.type;
return getFlowTypeOfPropertyAccess(node, /*prop*/ undefined, indexInfo.type, getAssignmentTargetKind(node));
}
if (right.escapedText && !checkAndReportErrorForExtendingInterface(node)) {
reportNonexistentProperty(right, type.flags & TypeFlags.TypeParameter && (type as TypeParameter).isThisType ? apparentType : type);
@ -15246,16 +15246,21 @@ namespace ts {
return unknownType;
}
}
return getFlowTypeOfPropertyAccess(node, prop, propType, assignmentKind);
}
// Only compute control flow type if this is a property access expression that isn't an
// assignment target, and the referenced property was declared as a variable, property,
// accessor, or optional method.
if (node.kind !== SyntaxKind.PropertyAccessExpression || assignmentKind === AssignmentKind.Definite ||
!(prop.flags & (SymbolFlags.Variable | SymbolFlags.Property | SymbolFlags.Accessor)) &&
!(prop.flags & SymbolFlags.Method && propType.flags & TypeFlags.Union)) {
return propType;
/**
* Only compute control flow type if this is a property access expression that isn't an
* assignment target, and the referenced property was declared as a variable, property,
* accessor, or optional method.
*/
function getFlowTypeOfPropertyAccess(node: PropertyAccessExpression | QualifiedName, prop: Symbol | undefined, type: Type, assignmentKind: AssignmentKind) {
if (node.kind !== SyntaxKind.PropertyAccessExpression ||
assignmentKind === AssignmentKind.Definite ||
prop && !(prop.flags & (SymbolFlags.Variable | SymbolFlags.Property | SymbolFlags.Accessor)) && !(prop.flags & SymbolFlags.Method && type.flags & TypeFlags.Union)) {
return type;
}
const flowType = getFlowTypeOfReference(node, propType);
const flowType = getFlowTypeOfReference(node, type);
return assignmentKind ? getBaseTypeOfLiteralType(flowType) : flowType;
}

20
tests/baselines/reference/controlFlowStringIndex.js Normal file
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@ -0,0 +1,20 @@
//// [controlFlowStringIndex.ts]
type A = {
other: number | null;
[index: string]: number | null
};
declare const value: A;
if (value.foo !== null) {
value.foo.toExponential()
value.other // should still be number | null
value.bar // should still be number | null
}
//// [controlFlowStringIndex.js]
"use strict";
if (value.foo !== null) {
value.foo.toExponential();
value.other; // should still be number | null
value.bar; // should still be number | null
}

32
tests/baselines/reference/controlFlowStringIndex.symbols Normal file
View file

@ -0,0 +1,32 @@
=== tests/cases/conformance/controlFlow/controlFlowStringIndex.ts ===
type A = {
>A : Symbol(A, Decl(controlFlowStringIndex.ts, 0, 0))
other: number | null;
>other : Symbol(other, Decl(controlFlowStringIndex.ts, 0, 10))
[index: string]: number | null
>index : Symbol(index, Decl(controlFlowStringIndex.ts, 2, 5))
};
declare const value: A;
>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
>A : Symbol(A, Decl(controlFlowStringIndex.ts, 0, 0))
if (value.foo !== null) {
>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
value.foo.toExponential()
>value.foo.toExponential : Symbol(Number.toExponential, Decl(lib.d.ts, --, --))
>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
>toExponential : Symbol(Number.toExponential, Decl(lib.d.ts, --, --))
value.other // should still be number | null
>value.other : Symbol(other, Decl(controlFlowStringIndex.ts, 0, 10))
>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
>other : Symbol(other, Decl(controlFlowStringIndex.ts, 0, 10))
value.bar // should still be number | null
>value : Symbol(value, Decl(controlFlowStringIndex.ts, 4, 13))
}

43
tests/baselines/reference/controlFlowStringIndex.types Normal file
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@ -0,0 +1,43 @@
=== tests/cases/conformance/controlFlow/controlFlowStringIndex.ts ===
type A = {
>A : A
other: number | null;
>other : number | null
>null : null
[index: string]: number | null
>index : string
>null : null
};
declare const value: A;
>value : A
>A : A
if (value.foo !== null) {
>value.foo !== null : boolean
>value.foo : number | null
>value : A
>foo : number | null
>null : null
value.foo.toExponential()
>value.foo.toExponential() : string
>value.foo.toExponential : (fractionDigits?: number | undefined) => string
>value.foo : number
>value : A
>foo : number
>toExponential : (fractionDigits?: number | undefined) => string
value.other // should still be number | null
>value.other : number | null
>value : A
>other : number | null
value.bar // should still be number | null
>value.bar : number | null
>value : A
>bar : number | null
}

11
tests/cases/conformance/controlFlow/controlFlowStringIndex.ts Normal file
View file

@ -0,0 +1,11 @@
// @strict: true
type A = {
other: number | null;
[index: string]: number | null
};
declare const value: A;
if (value.foo !== null) {
value.foo.toExponential()
value.other // should still be number | null
value.bar // should still be number | null
}