[[FIX]] Tolerate late definition of async function (#3618)

pirxpilot · web-flow · commit 5c256a29c517 · 2022-06-27T00:41:24.000-04:00
We used to mark `async function` as unreachable instead of treating it
as any other late function definition. This change makes jshint react to
`async` keyword in the same way as it reacted to `function` keyword.
diff --git a/src/jshint.js b/src/jshint.js
@@ -1850,8 +1850,9 @@ var JSHINT = (function() {
       if (t.reach) {
         return;
       }
+
       if (t.id !== "(endline)") {
-        if (t.id === "function") {
+        if (isFunction(t, i)) {
           if (state.option.latedef === true) {
             warning("W026", t);
           }
@@ -1862,6 +1863,16 @@ var JSHINT = (function() {
         break;
       }
     }
+
+    function isFunction(t, i) {
+      if (t.id === "function") {
+        return true;
+      }
+      if (t.id === "async") {
+        t = peek(i);
+        return t.id === "function";
+      }
+    }
   }
 
   /**
diff --git a/tests/unit/parser.js b/tests/unit/parser.js
@@ -8268,7 +8268,53 @@ exports.unreachable = {
       .test(src);
 
     test.done();
-  }
+  },
+  'async function': function (test) {
+    var src = [
+      "(function() {",
+      "  return f(4);",
+      "  async function f(p) {",
+      "    return p + 1;",
+      "  }",
+      "}());"
+    ];
+
+    TestRun(test)
+      .test(src, { esversion: 8, latedef: 'nofunc' });
+
+    test.done();
+  },
+  "async identifier": function (test) {
+    var src = [
+      "(function() {",
+      "  return f(4);",
+      "  async();",
+      "}());"
+    ];
+
+    TestRun(test)
+      .addError(3, 3, "Unreachable 'async' after 'return'.")
+      .test(src, { esversion: 8, latedef: "nofunc" });
+
+    test.done();
+  },
+   "async asi": function (test) {
+    var src = [
+      "(function() {",
+      "  return f(4);",
+      "  async",
+      "  function f(p) {",
+      "    return p + 1;",
+      "  }",
+      "}());"
+    ];
+
+    TestRun(test)
+      .addError(3, 3, "Unreachable 'async' after 'return'.")
+      .test(src, { esversion: 8, latedef: "nofunc", asi: true, expr: true });
+
+    test.done();
+  },
 };
 
 exports["test for 'break' in switch case + curly braces"] = function (test) {

Original file line number	Diff line number	Diff line change
`@@ -1850,8 +1850,9 @@ var JSHINT = (function() {`
`1850`	`1850`	`if (t.reach) {`
`1851`	`1851`	`return;`
`1852`	`1852`	`}`
	`1853`	`+`
`1853`	`1854`	`if (t.id !== "(endline)") {`
`1854`		`- if (t.id === "function") {`
	`1855`	`+ if (isFunction(t, i)) {`
`1855`	`1856`	`if (state.option.latedef === true) {`
`1856`	`1857`	`warning("W026", t);`
`1857`	`1858`	`}`
`@@ -1862,6 +1863,16 @@ var JSHINT = (function() {`
`1862`	`1863`	`break;`
`1863`	`1864`	`}`
`1864`	`1865`	`}`
	`1866`	`+`
	`1867`	`+ function isFunction(t, i) {`
	`1868`	`+ if (t.id === "function") {`
	`1869`	`+ return true;`
	`1870`	`+ }`
	`1871`	`+ if (t.id === "async") {`
	`1872`	`+ t = peek(i);`
	`1873`	`+ return t.id === "function";`
	`1874`	`+ }`
	`1875`	`+ }`
`1865`	`1876`	`}`
`1866`	`1877`
`1867`	`1878`	`/**`