Add disallowJSXAmbiguity option to the TS syntax plugin

packages/babel-plugin-syntax-typescript/package.json

@@ -24,7 +24,8 @@
     "@babel/core": "^7.0.0-0"
   },
   "devDependencies": {
-    "@babel/core": "workspace:*"
+    "@babel/core": "workspace:*",
+    "@babel/helper-plugin-test-runner": "workspace:*"
   },
   "engines": {
     "node": ">=6.9.0"

packages/babel-plugin-syntax-typescript/src/index.js

@@ -15,7 +15,7 @@ function removePlugin(plugins, name) {
   }
 }
 
-export default declare((api, { isTSX }) => {
+export default declare((api, { isTSX, disallowJSXAmbiguity }) => {
   api.assertVersion(7);
 
   return {
@@ -31,7 +31,10 @@ export default declare((api, { isTSX }) => {
       // in TS depends on the extensions, and is purely dependent on 'isTSX'.
       removePlugin(plugins, "jsx");
 
-      parserOpts.plugins.push("typescript", "classProperties");
+      parserOpts.plugins.push(
+        ["typescript", { disallowJSXAmbiguity }],
+        "classProperties",
+      );
 
       if (!process.env.BABEL_8_BREAKING) {
         // This is enabled by default since @babel/parser 7.1.5

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": [["syntax-typescript", { "disallowJSXAmbiguity": true }]]
+}

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/type-assertion/input.ts

@@ -0,0 +1 @@
+<T>x;

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/type-assertion/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "This syntax is reserved in files with the .mts or .cts extension. Use an `as` expression instead. (1:0)"
+}

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/type-parameter-unambiguous/input.ts

@@ -0,0 +1,2 @@
+<T,>() => 1;
+<T,>(x) => 1;

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/type-parameter-unambiguous/output.js

@@ -0,0 +1,3 @@
+<T>() => 1;
+
+<T>(x) => 1;

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/type-parameter/input.ts

@@ -0,0 +1,2 @@
+<T>() => 1;
+<T>(x) => 1;

packages/babel-plugin-syntax-typescript/test/fixtures/disallow-jsx-ambiguity/type-parameter/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "This syntax is reserved in files with the .mts or .cts extension. Add a trailing comma, as in `<T,>() => ...`. (1:0)"
+}

packages/babel-plugin-syntax-typescript/test/index.js

@@ -0,0 +1,3 @@
+import runner from "@babel/helper-plugin-test-runner";
+
+runner(import.meta.url);

yarn.lock

@@ -1995,6 +1995,7 @@ __metadata:
   resolution: "@babel/plugin-syntax-typescript@workspace:packages/babel-plugin-syntax-typescript"
   dependencies:
     "@babel/core": "workspace:*"
+    "@babel/helper-plugin-test-runner": "workspace:*"
     "@babel/helper-plugin-utils": "workspace:^7.14.5"
   peerDependencies:
     "@babel/core": ^7.0.0-0