diff --git a/src/printer.js b/src/printer.js
index 23ad6afb1..0558c7929 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -340,12 +340,12 @@ function genericPrintNoParens(path, options, print) {
       if (n.id) {
         parts.push(
           " ",
-          path.call(print, "id"),
-          path.call(print, "typeParameters")
+          path.call(print, "id")
         );
       }
 
       parts.push(
+        path.call(print, "typeParameters"),
         group(concat([
           "(",
           indent(options.tabWidth,
diff --git a/tests/annot/__snapshots__/jsfmt.spec.js.snap b/tests/annot/__snapshots__/jsfmt.spec.js.snap
index 4054561fb..130fa1686 100644
--- a/tests/annot/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/annot/__snapshots__/jsfmt.spec.js.snap
@@ -265,7 +265,7 @@ function insertMany<K, V>(
 }
 class Foo<A> {
   bar<B>() {
-    return function(a: A, b: B, c: C): void {
+    return function<C>(a: A, b: B, c: C): void {
       ([ a, b, c ]: [A, B, C]);
     };
   }
diff --git a/tests/async/__snapshots__/jsfmt.spec.js.snap b/tests/async/__snapshots__/jsfmt.spec.js.snap
index 3cd1397c9..33c166b7a 100644
--- a/tests/async/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/async/__snapshots__/jsfmt.spec.js.snap
@@ -187,7 +187,7 @@ class C {
 var e = async function() {
   
 };
-var et = async function(a: T) {
+var et = async function<T>(a: T) {
   
 };
 var n = new async function() {
@@ -487,7 +487,7 @@ class C {
 var e = async function() {
   await 1;
 };
-var et = async function(a: T) {
+var et = async function<T>(a: T) {
   await 1;
 };
 var n = new async function() {
diff --git a/tests/async_iteration/__snapshots__/jsfmt.spec.js.snap b/tests/async_iteration/__snapshots__/jsfmt.spec.js.snap
index f2f9d49ac..eb4a019d4 100644
--- a/tests/async_iteration/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/async_iteration/__snapshots__/jsfmt.spec.js.snap
@@ -78,7 +78,7 @@ async function* readLines(path) {
 }
 
 async function f() {
-  for await (const line of readLines(\"/path/to/file\")) {
+  for await (const line of readLines("/path/to/file")) {
     (line: void); // error: string ~> void
   }
 }
@@ -97,7 +97,7 @@ async function* readLines(path) {
   }
 }
 async function f() {
-  for await (const line of readLines(\"/path/to/file\")) {
+  for await (const line of readLines("/path/to/file")) {
     (line: void);
   }
 }
@@ -107,13 +107,13 @@ async function f() {
 exports[`test return.js 1`] = `
 "declare var gen: AsyncGenerator<void,string,void>;
 
-// You can pass whatever you like to return, it doesn\'t need to be related to
-// the AsyncGenerator\'s return type
+// You can pass whatever you like to return, it doesn't need to be related to
+// the AsyncGenerator's return type
 gen.return(0).then(result => {
   (result.value: void); // error: string | number ~> void
 });
 
-// However, a generator can \"refuse\" the return by catching an exception and
+// However, a generator can "refuse" the return by catching an exception and
 // yielding or returning internally.
 async function *refuse_return() {
   try {
@@ -122,16 +122,16 @@ async function *refuse_return() {
     return 0;
   }
 }
-refuse_return().return(\"string\").then(result => {
+refuse_return().return("string").then(result => {
   if (result.done) {
     (result.value: string); // error: number | void ~> string
   }
 });
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-// You can pass whatever you like to return, it doesn\'t need to be related to
-// the AsyncGenerator\'s return type
+// You can pass whatever you like to return, it doesn't need to be related to
+// the AsyncGenerator's return type
 // error: string | number ~> void
-// However, a generator can \"refuse\" the return by catching an exception and
+// However, a generator can "refuse" the return by catching an exception and
 // yielding or returning internally.
 // error: number | void ~> string
 declare var gen: AsyncGenerator<void, string, void>;
@@ -147,7 +147,7 @@ async function* refuse_return() {
     return 0;
   }
 }
-refuse_return().return(\"string\").then(
+refuse_return().return("string").then(
   result => {
     if (result.done) {
       (result.value: string);
@@ -167,7 +167,7 @@ exports[`test throw.js 1`] = `
 }
 
 (async () => {
-  catch_return().throw(\"\").then(({value}) => {
+  catch_return().throw("").then(({value}) => {
     if (value !== undefined) {
       (value: void); // error: number ~> void
     }
@@ -184,7 +184,7 @@ async function *yield_return() {
 }
 
 (async () => {
-  yield_return().throw(\"\").then(({value}) => {
+  yield_return().throw("").then(({value}) => {
     if (value !== undefined) {
       (value: void); // error: number ~> void
     }
@@ -201,7 +201,7 @@ async function* catch_return() {
   }
 }
 async () => {
-  catch_return().throw(\"\").then(
+  catch_return().throw("").then(
     ({ value }) => {
       if (value !== undefined) {
         (value: void);
@@ -218,7 +218,7 @@ async function* yield_return() {
   }
 }
 async () => {
-  yield_return().throw(\"\").then(
+  yield_return().throw("").then(
     ({ value }) => {
       if (value !== undefined) {
         (value: void);
diff --git a/tests/more_generics/__snapshots__/jsfmt.spec.js.snap b/tests/more_generics/__snapshots__/jsfmt.spec.js.snap
index fd73b9172..1388e9404 100644
--- a/tests/more_generics/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/more_generics/__snapshots__/jsfmt.spec.js.snap
@@ -38,13 +38,13 @@ function foo8<U>(x:U,y):U {
 /*
  foo8(0,void 0);
 */
-var foo1 = function(x: T): T {
+var foo1 = function<T>(x: T): T {
   return x;
 };
 function foo2<T, S>(x: T): S {
   return x;
 }
-var foo3 = function(x: T): T {
+var foo3 = function<T>(x: T): T {
   return foo3(x);
 };
 function foo4<T, S>(x: T): S {
@@ -54,7 +54,7 @@ var x = [  ];
 function foo5<T>(): Array<T> {
   return x;
 }
-var foo6 = function(x: R): R {
+var foo6 = function<R>(x: R): R {
   return foo1(x);
 };
 function foo7<R>(x: R): R {
diff --git a/tests/predicates-abstract/__snapshots__/jsfmt.spec.js.snap b/tests/predicates-abstract/__snapshots__/jsfmt.spec.js.snap
index c89941b61..af35dd379 100644
--- a/tests/predicates-abstract/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/predicates-abstract/__snapshots__/jsfmt.spec.js.snap
@@ -10,7 +10,7 @@ const barr = my_filter(arr, is_string);
 (barr: Array<string>);
 
 function is_string(x): %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // @flow
@@ -21,7 +21,7 @@ declare var arr: Array<mixed>;
 const barr = my_filter(arr, is_string);
 (barr: Array<string>);
 function is_string(x): %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 "
 `;
@@ -34,16 +34,16 @@ exports[`test filter-union.js 1`] = `
 
 declare function my_filter<T, P: $Pred<1>>(v: Array<T>, cb: P): Array<$Refine<T,P,1>>;
 
-type A = { kind: \'A\', u: number }
-type B = { kind: \'B\', v: string }
-type C = { kind: \'C\', y: boolean }
-type D = { kind: \'D\', x: boolean }
-type E = { kind: \'E\', y: boolean }
+type A = { kind: 'A', u: number }
+type B = { kind: 'B', v: string }
+type C = { kind: 'C', y: boolean }
+type D = { kind: 'D', x: boolean }
+type E = { kind: 'E', y: boolean }
 
 declare var ab: Array<A|B|C>;
 
-(my_filter(ab, (x): %checks => x.kind === \'A\'): Array<A>);    // OK
-(my_filter(ab, (x): %checks => x.kind !== \'A\'): Array<B|C>);  // OK
+(my_filter(ab, (x): %checks => x.kind === 'A'): Array<A>);    // OK
+(my_filter(ab, (x): %checks => x.kind !== 'A'): Array<B|C>);  // OK
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // @flow
 // Filter the contents of an array
@@ -51,14 +51,14 @@ declare var ab: Array<A|B|C>;
 // OK
 declare function my_filter<T, P: $Pred<1>>(v: Array<T>,
 cb: P): Array<$Refine<T, P, 1>>;
-type A = { kind: \"A\"; u: number };
-type B = { kind: \"B\"; v: string };
-type C = { kind: \"C\"; y: boolean };
-type D = { kind: \"D\"; x: boolean };
-type E = { kind: \"E\"; y: boolean };
+type A = { kind: "A"; u: number };
+type B = { kind: "B"; v: string };
+type C = { kind: "C"; y: boolean };
+type D = { kind: "D"; x: boolean };
+type E = { kind: "E"; y: boolean };
 declare var ab: Array<A | B | C>;
-(my_filter(ab, (x): %checks => x.kind === \"A\"): Array<A>);
-(my_filter(ab, (x): %checks => x.kind !== \"A\"): Array<B | C>);
+(my_filter(ab, (x): %checks => x.kind === "A"): Array<A>);
+(my_filter(ab, (x): %checks => x.kind !== "A"): Array<B | C>);
 "
 `;
 
@@ -66,7 +66,7 @@ exports[`test refine.js 1`] = `
 "// @flow
 
 /*
-  $Pred<N> is an \"abstract predicate type\", i.e. denotes a (function) type that
+  $Pred<N> is an "abstract predicate type", i.e. denotes a (function) type that
   refines N variables. So if \`cb\` is a function, then it should be refining
   exactly N argument. It is abstract in that we do not need to specify:
   (a) which variables are going to be refined (just the number), or (b) what
@@ -103,16 +103,16 @@ declare function refine2<T, P: $Pred<2>>(v: T, w: T, cb: P): $Refine<T,P,1>;
 // { if (cb(v, w)) { return w; } else { throw new Error(); } }
 
 function is_string(x): boolean %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 
 function is_string_and_number(x, y): %checks {
-  return typeof x === \"string\" && typeof y === \"number\";
+  return typeof x === "string" && typeof y === "number";
 }
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // @flow
 /*
-  $Pred<N> is an \"abstract predicate type\", i.e. denotes a (function) type that
+  $Pred<N> is an "abstract predicate type", i.e. denotes a (function) type that
   refines N variables. So if \`cb\` is a function, then it should be refining
   exactly N argument. It is abstract in that we do not need to specify:
   (a) which variables are going to be refined (just the number), or (b) what
@@ -143,10 +143,10 @@ var e = refine2(c, d, is_string_and_number);
 (e: string);
 declare function refine2<T, P: $Pred<2>>(v: T, w: T, cb: P): $Refine<T, P, 1>;
 function is_string(x): boolean %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 function is_string_and_number(x, y): %checks {
-  return typeof x === \"string\" && typeof y === \"number\";
+  return typeof x === "string" && typeof y === "number";
 }
 "
 `;
@@ -168,11 +168,11 @@ const d = my_filter(c, is_string_regular);
 (d: Array<string>);
 
 function is_string(x): boolean %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 
 function is_string_regular(x): boolean {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // @flow
@@ -187,10 +187,10 @@ declare var c: Array<mixed>;
 const d = my_filter(c, is_string_regular);
 (d: Array<string>);
 function is_string(x): boolean %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 function is_string_regular(x): boolean {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 "
 `;
@@ -203,16 +203,16 @@ exports[`test sanity-filter-union.js 1`] = `
 
 declare function my_filter<T, P: $Pred<1>>(v: Array<T>, cb: P): Array<$Refine<T,P,1>>;
 
-type A = { kind: \'A\', u: number }
-type B = { kind: \'B\', v: string }
-type C = { kind: \'C\', y: boolean }
-type D = { kind: \'D\', x: boolean }
-type E = { kind: \'E\', y: boolean }
+type A = { kind: 'A', u: number }
+type B = { kind: 'B', v: string }
+type C = { kind: 'C', y: boolean }
+type D = { kind: 'D', x: boolean }
+type E = { kind: 'E', y: boolean }
 
 declare var ab: Array<A|B|C>;
 
-(my_filter(ab, (x): %checks => x.kind === \'A\'): Array<B>);    // ERROR
-(my_filter(ab, (x): %checks => x.kind !== \'A\'): Array<A|C>);  // ERROR
+(my_filter(ab, (x): %checks => x.kind === 'A'): Array<B>);    // ERROR
+(my_filter(ab, (x): %checks => x.kind !== 'A'): Array<A|C>);  // ERROR
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // @flow
 // Filter the contents of an array
@@ -220,14 +220,14 @@ declare var ab: Array<A|B|C>;
 // ERROR
 declare function my_filter<T, P: $Pred<1>>(v: Array<T>,
 cb: P): Array<$Refine<T, P, 1>>;
-type A = { kind: \"A\"; u: number };
-type B = { kind: \"B\"; v: string };
-type C = { kind: \"C\"; y: boolean };
-type D = { kind: \"D\"; x: boolean };
-type E = { kind: \"E\"; y: boolean };
+type A = { kind: "A"; u: number };
+type B = { kind: "B"; v: string };
+type C = { kind: "C"; y: boolean };
+type D = { kind: "D"; x: boolean };
+type E = { kind: "E"; y: boolean };
 declare var ab: Array<A | B | C>;
-(my_filter(ab, (x): %checks => x.kind === \"A\"): Array<B>);
-(my_filter(ab, (x): %checks => x.kind !== \"A\"): Array<A | C>);
+(my_filter(ab, (x): %checks => x.kind === "A"): Array<B>);
+(my_filter(ab, (x): %checks => x.kind !== "A"): Array<A | C>);
 "
 `;
 
@@ -254,7 +254,7 @@ var e = refine3(c, d, e, is_string_and_number);
 (e: string);
 
 function is_string_and_number(x, y): %checks {
-  return typeof x === \"string\" && typeof y === \"number\";
+  return typeof x === "string" && typeof y === "number";
 }
 
 
@@ -266,15 +266,15 @@ var e = refine(a, is_string_regular);   // ERROR: is_string_regular is not a
 ////////////////////////////////////////////////////////////////////////////////
 
 function is_string(x): %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 
 function is_string_regular(x)  {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 
 function is_string_and_number(x, y): %checks {
-  return typeof x === \"string\" && typeof y === \"number\";
+  return typeof x === "string" && typeof y === "number";
 }
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 // @flow
@@ -300,18 +300,18 @@ cb: P): $Refine<T, P, 1>;
 var e = refine3(c, d, e, is_string_and_number);
 (e: string);
 function is_string_and_number(x, y): %checks {
-  return typeof x === \"string\" && typeof y === \"number\";
+  return typeof x === "string" && typeof y === "number";
 }
 var e = refine(a, is_string_regular);
 (e: number);
 function is_string(x): %checks {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 function is_string_regular(x) {
-  return typeof x === \"string\";
+  return typeof x === "string";
 }
 function is_string_and_number(x, y): %checks {
-  return typeof x === \"string\" && typeof y === \"number\";
+  return typeof x === "string" && typeof y === "number";
 }
 "
 `;
diff --git a/tests_config/run_spec.js b/tests_config/run_spec.js
index 3968a14a1..aa82cec7e 100644
--- a/tests_config/run_spec.js
+++ b/tests_config/run_spec.js
@@ -11,7 +11,7 @@ function run_spec(dirname) {
 
       if (!RUN_AST_TESTS) {
         const source = read(path);
-        const output = prettyprint(source);
+        const output = prettyprint(source, path);
         test(filename, () => {
           expect(source + '~'.repeat(80) + '\n' + output).toMatchSnapshot();
         });
@@ -24,7 +24,7 @@ function run_spec(dirname) {
         let ppast;
         let pperr = null;
         try {
-          ppast = parse(prettyprint(source));
+          ppast = parse(prettyprint(source, path));
         }
         catch(e) {
           pperr = e.stack;
@@ -68,8 +68,8 @@ function parse(string) {
   return stripLocation(flowParser.parse(string));
 }
 
-function prettyprint(src) {
-  return jscodefmt.format(src);
+function prettyprint(src, filename) {
+  return jscodefmt.format(src, { filename });
 }
 
 function read(filename) {