Don't crash if there's no JSX.Element during SFC resolution

Fixes microsoft#7286

Author: RyanCavanaugh

src/compiler/checker.ts

@@ -8797,18 +8797,20 @@ namespace ts {
                     if (!elemClassType || !isTypeAssignableTo(elemInstanceType, elemClassType)) {
                         // Is this is a stateless function component? See if its single signature's return type is
                         // assignable to the JSX Element Type
-                        const elemType = checkExpression(node.tagName);
-                        const callSignatures = elemType && getSignaturesOfType(elemType, SignatureKind.Call);
-                        const callSignature = callSignatures && callSignatures.length > 0 && callSignatures[0];
-                        const callReturnType = callSignature && getReturnTypeOfSignature(callSignature);
-                        let paramType = callReturnType && (callSignature.parameters.length === 0 ? emptyObjectType : getTypeOfSymbol(callSignature.parameters[0]));
-                        if (callReturnType && isTypeAssignableTo(callReturnType, jsxElementType)) {
-                            // Intersect in JSX.IntrinsicAttributes if it exists
-                            const intrinsicAttributes = getJsxType(JsxNames.IntrinsicAttributes);
-                            if (intrinsicAttributes !== unknownType) {
-                                paramType = intersectTypes(intrinsicAttributes, paramType);
+                        if (jsxElementType) {
+                            const elemType = checkExpression(node.tagName);
+                            const callSignatures = elemType && getSignaturesOfType(elemType, SignatureKind.Call);
+                            const callSignature = callSignatures && callSignatures.length > 0 && callSignatures[0];
+                            const callReturnType = callSignature && getReturnTypeOfSignature(callSignature);
+                            let paramType = callReturnType && (callSignature.parameters.length === 0 ? emptyObjectType : getTypeOfSymbol(callSignature.parameters[0]));
+                            if (callReturnType && isTypeAssignableTo(callReturnType, jsxElementType)) {
+                                // Intersect in JSX.IntrinsicAttributes if it exists
+                                const intrinsicAttributes = getJsxType(JsxNames.IntrinsicAttributes);
+                                if (intrinsicAttributes !== unknownType) {
+                                    paramType = intersectTypes(intrinsicAttributes, paramType);
+                                }
+                                return links.resolvedJsxType = paramType;
                             }
-                            return links.resolvedJsxType = paramType;
                         }
                     }
 

tests/baselines/reference/contextuallyTypedStringLiteralsInJsxAttributes01.errors.txt

@@ -1,15 +1,18 @@
-tests/cases/conformance/types/contextualTypes/jsxAttributes/contextuallyTypedStringLiteralsInJsxAttributes01.tsx(13,15): error TS2322: Type '"f"' is not assignable to type '"A" | "B" | "C"'.
+tests/cases/conformance/types/contextualTypes/jsxAttributes/contextuallyTypedStringLiteralsInJsxAttributes01.tsx(16,15): error TS2322: Type '"f"' is not assignable to type '"A" | "B" | "C"'.
   Type '"f"' is not assignable to type '"C"'.
-tests/cases/conformance/types/contextualTypes/jsxAttributes/contextuallyTypedStringLiteralsInJsxAttributes01.tsx(14,15): error TS2322: Type '"f"' is not assignable to type '"A" | "B" | "C"'.
+tests/cases/conformance/types/contextualTypes/jsxAttributes/contextuallyTypedStringLiteralsInJsxAttributes01.tsx(17,15): error TS2322: Type '"f"' is not assignable to type '"A" | "B" | "C"'.
   Type '"f"' is not assignable to type '"C"'.
 
 
 ==== tests/cases/conformance/types/contextualTypes/jsxAttributes/contextuallyTypedStringLiteralsInJsxAttributes01.tsx (2 errors) ====
 
     namespace JSX {
-        interface IntrinsicElements {
+        export interface IntrinsicElements {
             span: {};
         }
+        export interface Element {
+    		something?: any;
+        }
     }
 
     const FooComponent = (props: { foo: "A" | "B" | "C" }) => <span>{props.foo}</span>;

tests/baselines/reference/contextuallyTypedStringLiteralsInJsxAttributes01.js

@@ -1,9 +1,12 @@
 //// [contextuallyTypedStringLiteralsInJsxAttributes01.tsx]
 
 namespace JSX {
-    interface IntrinsicElements {
+    export interface IntrinsicElements {
         span: {};
     }
+    export interface Element {
+		something?: any;
+    }
 }
 
 const FooComponent = (props: { foo: "A" | "B" | "C" }) => <span>{props.foo}</span>;
@@ -24,7 +27,13 @@ var FooComponent = function (props) { return <span>{props.foo}</span>; };
 
 //// [contextuallyTypedStringLiteralsInJsxAttributes01.d.ts]
 declare namespace JSX {
+    interface IntrinsicElements {
+        span: {};
+    }
+    interface Element {
+        something?: any;
+    }
 }
 declare const FooComponent: (props: {
     foo: "A" | "B" | "C";
-}) => any;
+}) => JSX.Element;

tests/baselines/reference/tsxAttributeResolution13.js

@@ -0,0 +1,9 @@
+//// [test.tsx]
+
+function Test() { }
+<Test></Test>
+
+
+//// [test.jsx]
+function Test() { }
+<Test></Test>;

tests/baselines/reference/tsxAttributeResolution13.symbols

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/jsx/test.tsx ===
+
+function Test() { }
+>Test : Symbol(Test, Decl(test.tsx, 0, 0))
+
+<Test></Test>
+>Test : Symbol(Test, Decl(test.tsx, 0, 0))
+>Test : Symbol(Test, Decl(test.tsx, 0, 0))
+

tests/baselines/reference/tsxAttributeResolution13.types

@@ -0,0 +1,10 @@
+=== tests/cases/conformance/jsx/test.tsx ===
+
+function Test() { }
+>Test : () => void
+
+<Test></Test>
+><Test></Test> : any
+>Test : any
+>Test : any
+

tests/cases/conformance/jsx/tsxAttributeResolution13.tsx

@@ -0,0 +1,5 @@
+//@jsx: preserve
+
+//@filename: test.tsx
+function Test() { }
+<Test></Test>

tests/cases/conformance/types/contextualTypes/jsxAttributes/contextuallyTypedStringLiteralsInJsxAttributes01.tsx

@@ -2,9 +2,12 @@
 // @declaration: true
 
 namespace JSX {
-    interface IntrinsicElements {
+    export interface IntrinsicElements {
         span: {};
     }
+    export interface Element {
+		something?: any;
+    }
 }
 
 const FooComponent = (props: { foo: "A" | "B" | "C" }) => <span>{props.foo}</span>;