Prevent valid JSX from being seen as the start of a generic arrow function, fix crashes (#52450)

Author: jakebailey

src/compiler/parser.ts

@@ -5201,6 +5201,7 @@ namespace Parser {
                         switch (fourth) {
                             case SyntaxKind.EqualsToken:
                             case SyntaxKind.GreaterThanToken:
+                            case SyntaxKind.SlashToken:
                                 return false;
                             default:
                                 return true;

src/compiler/utilities.ts

@@ -9079,7 +9079,7 @@ export function rangeOfNode(node: Node): TextRange {
 export function rangeOfTypeParameters(sourceFile: SourceFile, typeParameters: NodeArray<TypeParameterDeclaration>): TextRange {
     // Include the `<>`
     const pos = typeParameters.pos - 1;
-    const end = skipTrivia(sourceFile.text, typeParameters.end) + 1;
+    const end = Math.min(sourceFile.text.length, skipTrivia(sourceFile.text, typeParameters.end) + 1);
     return { pos, end };
 }
 

tests/baselines/reference/parseJsxExtends1.js

@@ -0,0 +1,18 @@
+//// [index.tsx]
+declare const React: any;
+
+export function Foo() {
+    // No error; "const" is lowercase and therefore intrinsic.
+    return <const T extends/>
+}
+
+
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.Foo = void 0;
+function Foo() {
+    // No error; "const" is lowercase and therefore intrinsic.
+    return React.createElement("const", { T: true, extends: true });
+}
+exports.Foo = Foo;

tests/baselines/reference/parseJsxExtends1.symbols

@@ -0,0 +1,13 @@
+=== tests/cases/compiler/index.tsx ===
+declare const React: any;
+>React : Symbol(React, Decl(index.tsx, 0, 13))
+
+export function Foo() {
+>Foo : Symbol(Foo, Decl(index.tsx, 0, 25))
+
+    // No error; "const" is lowercase and therefore intrinsic.
+    return <const T extends/>
+>T : Symbol(T, Decl(index.tsx, 4, 17))
+>extends : Symbol(extends, Decl(index.tsx, 4, 19))
+}
+

tests/baselines/reference/parseJsxExtends1.types

@@ -0,0 +1,15 @@
+=== tests/cases/compiler/index.tsx ===
+declare const React: any;
+>React : any
+
+export function Foo() {
+>Foo : () => any
+
+    // No error; "const" is lowercase and therefore intrinsic.
+    return <const T extends/>
+><const T extends/> : error
+>const : any
+>T : true
+>extends : true
+}
+

tests/baselines/reference/parseJsxExtends2.errors.txt

@@ -0,0 +1,13 @@
+tests/cases/compiler/index.tsx(5,13): error TS2304: Cannot find name 'T'.
+
+
+==== tests/cases/compiler/index.tsx (1 errors) ====
+    declare const React: any;
+    
+    export function Foo() {
+        // Error: T is not declared.
+        return <T extends/>
+                ~
+!!! error TS2304: Cannot find name 'T'.
+    }
+    

tests/baselines/reference/parseJsxExtends2.js

@@ -0,0 +1,18 @@
+//// [index.tsx]
+declare const React: any;
+
+export function Foo() {
+    // Error: T is not declared.
+    return <T extends/>
+}
+
+
+//// [index.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.Foo = void 0;
+function Foo() {
+    // Error: T is not declared.
+    return React.createElement(T, { extends: true });
+}
+exports.Foo = Foo;

tests/baselines/reference/parseJsxExtends2.symbols

@@ -0,0 +1,12 @@
+=== tests/cases/compiler/index.tsx ===
+declare const React: any;
+>React : Symbol(React, Decl(index.tsx, 0, 13))
+
+export function Foo() {
+>Foo : Symbol(Foo, Decl(index.tsx, 0, 25))
+
+    // Error: T is not declared.
+    return <T extends/>
+>extends : Symbol(extends, Decl(index.tsx, 4, 13))
+}
+

tests/baselines/reference/parseJsxExtends2.types

@@ -0,0 +1,14 @@
+=== tests/cases/compiler/index.tsx ===
+declare const React: any;
+>React : any
+
+export function Foo() {
+>Foo : () => any
+
+    // Error: T is not declared.
+    return <T extends/>
+><T extends/> : any
+>T : any
+>extends : true
+}
+

tests/cases/compiler/parseJsxExtends1.ts

@@ -0,0 +1,9 @@
+// @jsx: react
+// @filename: index.tsx
+
+declare const React: any;
+
+export function Foo() {
+    // No error; "const" is lowercase and therefore intrinsic.
+    return <const T extends/>
+}

tests/cases/compiler/parseJsxExtends2.ts

@@ -0,0 +1,9 @@
+// @jsx: react
+// @filename: index.tsx
+
+declare const React: any;
+
+export function Foo() {
+    // Error: T is not declared.
+    return <T extends/>
+}

tests/cases/fourslash/jsxElementExtendsNoCrash1.ts

@@ -0,0 +1,6 @@
+/// <reference path="fourslash.ts" />
+
+// @filename: index.tsx
+//// <const T extends/>
+
+verify.getSuggestionDiagnostics([]);

tests/cases/fourslash/jsxElementExtendsNoCrash2.ts

@@ -0,0 +1,6 @@
+/// <reference path="fourslash.ts" />
+
+// @filename: index.tsx
+//// <T extends/>
+
+verify.getSuggestionDiagnostics([]);

tests/cases/fourslash/jsxElementExtendsNoCrash3.ts

@@ -0,0 +1,6 @@
+/// <reference path="fourslash.ts" />
+
+// @filename: index.tsx
+//// <T extends /=>
+
+verify.getSuggestionDiagnostics([]);