206 lines
6.4 KiB
Plaintext
206 lines
6.4 KiB
Plaintext
exports[`test test.js 1`] = `
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"var x: { } = { foo: 0 };
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var y: { foo?: string } = x; // OK in TypeScript, not OK in Flow
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var z: string = y.foo || \"\";
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var o = { };
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y = o; // OK; we know that narrowing could not have happened
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o.foo = 0; // future widening is constrained
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function bar(config: { foo?: number }) {}
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bar({});
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bar({foo: \"\"});
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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var x: {} = { foo: 0 };
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var y: { foo?: string } = x;
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// OK in TypeScript, not OK in Flow
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var z: string = y.foo || \"\";
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var o = {};
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y = o;
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// OK; we know that narrowing could not have happened
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o.foo = 0;
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// future widening is constrained
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function bar(config: { foo?: number }) {
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}
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bar({});
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bar({ foo: \"\" });
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"
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`;
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exports[`test test2.js 1`] = `
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"var a: { foo?: string } = {};
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a.foo = undefined; // This is not an error
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a.foo = null; // But this is an error
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var b: { foo?: ?string } = {};
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b.foo = undefined; // This is fine
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b.foo = null; // Also fine
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var c: { foo?: string } = { foo: undefined }; // This is not an error
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var d: { foo?: string } = { foo: null }; // But this is an error
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var e: { foo?: ?string } = { foo: undefined }; // This is fine
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var f: { foo?: ?string } = { foo: null }; // Also fine
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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var a: { foo?: string } = {};
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a.foo = undefined;
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// This is not an error
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a.foo = null;
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// But this is an error
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var b: { foo?: ?string } = {};
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b.foo = undefined;
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// This is fine
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b.foo = null;
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// Also fine
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var c: { foo?: string } = { foo: undefined };
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// This is not an error
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var d: { foo?: string } = { foo: null };
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// But this is an error
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var e: { foo?: ?string } = { foo: undefined };
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// This is fine
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var f: { foo?: ?string } = { foo: null }; // Also fine
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"
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`;
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exports[`test test3.js 1`] = `
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"// @flow
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/*
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object literals are sealed. this is simply a heuristic
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decision: most of the time, the rule gives the \'right\'
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errors.
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an exception is when a literal is used as an initializer
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for an lvalue whose type specifies optional properties
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missing from the literal, as below.
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the problem becomes visible when a property assignment
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is then used to (legitimately) extend the object with an
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optional property - the variable\'s specific (path-
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dependent) type has become that of the literal which.
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without adjustment, will reject the property addition.
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the solution in cases where a sealed object type (as from
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an object literal) flows to an object type with optional
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properties, is to have the sealed type acquire the optional
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properties.
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*/
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// x has optional property b.
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// (note that the initializer here does not play into
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// the problem, it\'s just a placeholder. initializers
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// do not narrow the types of annotated variables as do
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// subsequent assignments.)
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//
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var x: { a: number, b?: number } = { a: 0 };
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// now assign an object literal lacking property b.
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// the literal\'s type is sealed and has only a at creation.
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// but it then flows, specific ~> general, to x\'s annotation
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// type. at that point, it acquires b as an optional property.
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//
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x = { a: 0 };
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// ...which allows this assignment to take place.
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x.b = 1;
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// T7810506
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class A {
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x: { a: number, b?: string };
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foo() {
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// Something similar should happen here, but doesn\'t: the problem is
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// made explicit by adding generics (see test3_failure.js introduced by
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// D2747512). There is a race between writing b on the object literal
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// type and adding b as an optional property to it, since in general we
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// cannot guarantee that the flow from the object literal to the
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// annotation will be processed before the flow involving the
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// access. Here we lose the race and get an error on the write.
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this.x = { a: 123 };
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this.x.b = \'hello\';
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}
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}
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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// @flow
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/*
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object literals are sealed. this is simply a heuristic
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decision: most of the time, the rule gives the \'right\'
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errors.
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an exception is when a literal is used as an initializer
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for an lvalue whose type specifies optional properties
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missing from the literal, as below.
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the problem becomes visible when a property assignment
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is then used to (legitimately) extend the object with an
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optional property - the variable\'s specific (path-
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dependent) type has become that of the literal which.
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without adjustment, will reject the property addition.
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the solution in cases where a sealed object type (as from
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an object literal) flows to an object type with optional
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properties, is to have the sealed type acquire the optional
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properties.
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*/
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// x has optional property b.
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// (note that the initializer here does not play into
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// the problem, it\'s just a placeholder. initializers
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// do not narrow the types of annotated variables as do
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// subsequent assignments.)
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//
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var x: { a: number, b?: number } = { a: 0 };
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// now assign an object literal lacking property b.
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// the literal\'s type is sealed and has only a at creation.
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// but it then flows, specific ~> general, to x\'s annotation
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// type. at that point, it acquires b as an optional property.
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//
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x = { a: 0 };
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// ...which allows this assignment to take place.
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x.b = 1;
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// T7810506
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class A {
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x: { a: number, b?: string };
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foo() {
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// Something similar should happen here, but doesn\'t: the problem is
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// made explicit by adding generics (see test3_failure.js introduced by
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// D2747512). There is a race between writing b on the object literal
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// type and adding b as an optional property to it, since in general we
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// cannot guarantee that the flow from the object literal to the
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// annotation will be processed before the flow involving the
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// access. Here we lose the race and get an error on the write.
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this.x = { a: 123 };
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this.x.b = \"hello\";
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}
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}
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"
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`;
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exports[`test test3_failure.js 1`] = `
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"// generalization of failure in test3.js
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class A<O: {x: { a: number, b?: string}}> {
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o: O;
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foo() {
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this.o.x = { a: 123 };
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this.o.x.b = \'hello\'; // this is a spurious error (see test3.js for details)
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}
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}
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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// generalization of failure in test3.js
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class A<O: { x: { a: number, b?: string } }> {
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o: O;
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foo() {
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this.o.x = { a: 123 };
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this.o.x.b = \"hello\"; // this is a spurious error (see test3.js for details)
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}
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}
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"
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`;
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