Remove for-each-in syntax (#9585)

src/language-js/printer-estree.js

@@ -1716,10 +1716,9 @@ function printPathNoParens(path, options, print, args) {
         ])
       );
     case "ForInStatement":
-      // Note: esprima can't actually parse "for each (".
       return group(
         concat([
-          n.each ? "for each (" : "for (",
+          "for (",
           path.call(print, "left"),
           " in ",
           path.call(print, "right"),

tests/misc/errors/invalid/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,37 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`snippet: #0 error test 1`] = `
+"Unexpected token, expected \\"(\\" (1:5)
+> 1 | for each (a in b) {}
+    |     ^"
+`;
+
+exports[`snippet: #0 error test 2`] = `
+"Unexpected identifier, expected the token \`(\` (1:5)
+> 1 | for each (a in b) {}
+    |     ^^^^"
+`;
+
+exports[`snippet: #0 error test 3`] = `
+"'(' expected. (1:5)
+> 1 | for each (a in b) {}
+    |     ^"
+`;
+
+exports[`snippet: #0 error test 4`] = `
+"Unexpected token, expected \\"(\\" (1:5)
+> 1 | for each (a in b) {}
+    |     ^"
+`;
+
+exports[`snippet: #0 error test 5`] = `
+"Unexpected token, expected \\"(\\" (1:5)
+> 1 | for each (a in b) {}
+    |     ^"
+`;
+
+exports[`snippet: #0 error test 6`] = `
+"Unexpected token each (1:5)
+> 1 | for each (a in b) {}
+    |     ^"
+`;

tests/misc/errors/invalid/jsfmt.spec.js

@@ -0,0 +1,16 @@
+for (const parser of [
+  "babel",
+  "flow",
+  "typescript",
+  "babel-flow",
+  "babel-ts",
+  "espree",
+]) {
+  run_spec(
+    {
+      dirname: __dirname,
+      snippets: ["for each (a in b) {}"],
+    },
+    [parser]
+  );
+}