Merge pull request microsoft#21345 from Microsoft/fix-jsx-attribute-checking

Fix JSX attribute checking when spreading unions

Author: sandersn

src/compiler/checker.ts

@@ -15310,7 +15310,7 @@ namespace ts {
 
             // If the targetAttributesType is an emptyObjectType, indicating that there is no property named 'props' on this instance type.
             // but there exists a sourceAttributesType, we need to explicitly give an error as normal assignability check allow excess properties and will pass.
-            if (targetAttributesType === emptyObjectType && (isTypeAny(sourceAttributesType) || (<ResolvedType>sourceAttributesType).properties.length > 0)) {
+            if (targetAttributesType === emptyObjectType && (isTypeAny(sourceAttributesType) || getPropertiesOfType(<ResolvedType>sourceAttributesType).length > 0)) {
                 error(openingLikeElement, Diagnostics.JSX_element_class_does_not_support_attributes_because_it_does_not_have_a_0_property, unescapeLeadingUnderscores(getJsxElementPropertiesName()));
             }
             else {

tests/baselines/reference/tsxSpreadAttributesResolution17.js

@@ -0,0 +1,47 @@
+//// [file.tsx]
+declare global {
+    namespace JSX {
+        interface Element {}
+        interface ElementAttributesProperty { props: {} }
+    }
+}
+declare var React: any;
+
+export class Empty extends React.Component<{}, {}> {
+    render() {
+        return <div>Hello</div>;
+    }
+}
+
+declare const obj: { a: number | undefined } | undefined;
+
+// OK
+let unionedSpread = <Empty {...obj} />;
+
+
+//// [file.jsx]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+exports.__esModule = true;
+var Empty = /** @class */ (function (_super) {
+    __extends(Empty, _super);
+    function Empty() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    Empty.prototype.render = function () {
+        return <div>Hello</div>;
+    };
+    return Empty;
+}(React.Component));
+exports.Empty = Empty;
+// OK
+var unionedSpread = <Empty {...obj}/>;

tests/baselines/reference/tsxSpreadAttributesResolution17.symbols

@@ -0,0 +1,41 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare global {
+>global : Symbol(global, Decl(file.tsx, 0, 0))
+
+    namespace JSX {
+>JSX : Symbol(JSX, Decl(file.tsx, 0, 16))
+
+        interface Element {}
+>Element : Symbol(Element, Decl(file.tsx, 1, 19))
+
+        interface ElementAttributesProperty { props: {} }
+>ElementAttributesProperty : Symbol(ElementAttributesProperty, Decl(file.tsx, 2, 28))
+>props : Symbol(ElementAttributesProperty.props, Decl(file.tsx, 3, 45))
+    }
+}
+declare var React: any;
+>React : Symbol(React, Decl(file.tsx, 6, 11))
+
+export class Empty extends React.Component<{}, {}> {
+>Empty : Symbol(Empty, Decl(file.tsx, 6, 23))
+>React : Symbol(React, Decl(file.tsx, 6, 11))
+
+    render() {
+>render : Symbol(Empty.render, Decl(file.tsx, 8, 52))
+
+        return <div>Hello</div>;
+>div : Symbol(unknown)
+>div : Symbol(unknown)
+    }
+}
+
+declare const obj: { a: number | undefined } | undefined;
+>obj : Symbol(obj, Decl(file.tsx, 14, 13))
+>a : Symbol(a, Decl(file.tsx, 14, 20))
+
+// OK
+let unionedSpread = <Empty {...obj} />;
+>unionedSpread : Symbol(unionedSpread, Decl(file.tsx, 17, 3))
+>Empty : Symbol(Empty, Decl(file.tsx, 6, 23))
+>obj : Symbol(obj, Decl(file.tsx, 14, 13))
+

tests/baselines/reference/tsxSpreadAttributesResolution17.types

@@ -0,0 +1,45 @@
+=== tests/cases/conformance/jsx/file.tsx ===
+declare global {
+>global : any
+
+    namespace JSX {
+>JSX : any
+
+        interface Element {}
+>Element : Element
+
+        interface ElementAttributesProperty { props: {} }
+>ElementAttributesProperty : ElementAttributesProperty
+>props : {}
+    }
+}
+declare var React: any;
+>React : any
+
+export class Empty extends React.Component<{}, {}> {
+>Empty : Empty
+>React.Component : any
+>React : any
+>Component : any
+
+    render() {
+>render : () => JSX.Element
+
+        return <div>Hello</div>;
+><div>Hello</div> : JSX.Element
+>div : any
+>div : any
+    }
+}
+
+declare const obj: { a: number | undefined } | undefined;
+>obj : { a: number | undefined; } | undefined
+>a : number | undefined
+
+// OK
+let unionedSpread = <Empty {...obj} />;
+>unionedSpread : JSX.Element
+><Empty {...obj} /> : JSX.Element
+>Empty : typeof Empty
+>obj : { a: number | undefined; } | undefined
+

tests/cases/conformance/jsx/tsxSpreadAttributesResolution17.tsx

@@ -0,0 +1,25 @@
+// @strictNullChecks: true
+// @filename: file.tsx
+// @jsx: preserve
+// @noLib: true
+// @skipLibCheck: true
+// @libFiles: lib.d.ts
+
+declare global {
+    namespace JSX {
+        interface Element {}
+        interface ElementAttributesProperty { props: {} }
+    }
+}
+declare var React: any;
+
+export class Empty extends React.Component<{}, {}> {
+    render() {
+        return <div>Hello</div>;
+    }
+}
+
+declare const obj: { a: number | undefined } | undefined;
+
+// OK
+let unionedSpread = <Empty {...obj} />;