diff --git a/src/fast-path.js b/src/fast-path.js
index 6d83ccad..65cd9a4c 100644
--- a/src/fast-path.js
+++ b/src/fast-path.js
@@ -6,6 +6,7 @@ var util = require("./util");
 var n = types.namedTypes;
 var isArray = types.builtInTypes.array;
 var isNumber = types.builtInTypes.number;
+var startsWithNoLookaheadToken = util.startsWithNoLookaheadToken;
 
 function FastPath(value) {
   assert.ok(this instanceof FastPath);
@@ -464,7 +465,6 @@ FPp.needsParens = function() {
         case "ExportDefaultDeclaration":
         case "AwaitExpression":
         case "JSXSpreadAttribute":
-        case "ArrowFunctionExpression":
           return true;
 
         case "NewExpression":
@@ -554,58 +554,4 @@ function containsCallExpression(node) {
   return false;
 }
 
-// Tests if an expression starts with `{`, or (if forbidFunctionAndClass holds) `function` or `class`.
-// Will be overzealous if there's already necessary grouping parentheses.
-function startsWithNoLookaheadToken(node, forbidFunctionAndClass) {
-  node = getLeftMost(node);
-  switch (node.type) {
-    case "FunctionExpression":
-    case "ClassExpression":
-      return forbidFunctionAndClass;
-    case "ObjectExpression":
-      return true;
-    case "MemberExpression":
-      return startsWithNoLookaheadToken(node.object, forbidFunctionAndClass);
-    case "TaggedTemplateExpression":
-      if (node.tag.type === "FunctionExpression") {
-        // IIFEs are always already parenthesized
-        return false;
-      }
-      return startsWithNoLookaheadToken(node.tag, forbidFunctionAndClass);
-    case "CallExpression":
-      if (node.callee.type === "FunctionExpression") {
-        // IIFEs are always already parenthesized
-        return false;
-      }
-      return startsWithNoLookaheadToken(node.callee, forbidFunctionAndClass);
-    case "ConditionalExpression":
-      return startsWithNoLookaheadToken(node.test, forbidFunctionAndClass);
-    case "UpdateExpression":
-      return (
-        !node.prefix &&
-        startsWithNoLookaheadToken(node.argument, forbidFunctionAndClass)
-      );
-    case "BindExpression":
-      return (
-        node.object &&
-        startsWithNoLookaheadToken(node.object, forbidFunctionAndClass)
-      );
-    case "SequenceExpression":
-      return startsWithNoLookaheadToken(
-        node.expressions[0],
-        forbidFunctionAndClass
-      );
-    default:
-      return false;
-  }
-}
-
-function getLeftMost(node) {
-  if (node.left) {
-    return getLeftMost(node.left);
-  } else {
-    return node;
-  }
-}
-
 module.exports = FastPath;
diff --git a/src/printer.js b/src/printer.js
index f3dd181a..3a3f7ab5 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -386,12 +386,29 @@ function genericPrintNoParens(path, options, print, args) {
       // with the opening (.
       const shouldAddSoftLine = args && args.expandLastArg;
 
+      // In order to avoid confusion between
+      // a => a ? a : a
+      // a <= a ? a : a
+      const shouldAddParens =
+        n.body.type === "ConditionalExpression" &&
+        !util.startsWithNoLookaheadToken(
+          n.body,
+          /* forbidFunctionAndClass */ false
+        );
+
       return group(
         concat([
           concat(parts),
           group(
             concat([
-              indent(concat([line, body])),
+              indent(
+                concat([
+                  line,
+                  shouldAddParens ? ifBreak("", "(") : "",
+                  body,
+                  shouldAddParens ? ifBreak("", ")") : ""
+                ])
+              ),
               shouldAddSoftLine
                 ? concat([
                     ifBreak(shouldPrintComma(options, "all") ? "," : ""),
diff --git a/src/util.js b/src/util.js
index 190438dd..1d32ba6c 100644
--- a/src/util.js
+++ b/src/util.js
@@ -267,6 +267,61 @@ function getPrecedence(op) {
   return PRECEDENCE[op];
 }
 
+
+// Tests if an expression starts with `{`, or (if forbidFunctionAndClass holds) `function` or `class`.
+// Will be overzealous if there's already necessary grouping parentheses.
+function startsWithNoLookaheadToken(node, forbidFunctionAndClass) {
+  node = getLeftMost(node);
+  switch (node.type) {
+    case "FunctionExpression":
+    case "ClassExpression":
+      return forbidFunctionAndClass;
+    case "ObjectExpression":
+      return true;
+    case "MemberExpression":
+      return startsWithNoLookaheadToken(node.object, forbidFunctionAndClass);
+    case "TaggedTemplateExpression":
+      if (node.tag.type === "FunctionExpression") {
+        // IIFEs are always already parenthesized
+        return false;
+      }
+      return startsWithNoLookaheadToken(node.tag, forbidFunctionAndClass);
+    case "CallExpression":
+      if (node.callee.type === "FunctionExpression") {
+        // IIFEs are always already parenthesized
+        return false;
+      }
+      return startsWithNoLookaheadToken(node.callee, forbidFunctionAndClass);
+    case "ConditionalExpression":
+      return startsWithNoLookaheadToken(node.test, forbidFunctionAndClass);
+    case "UpdateExpression":
+      return (
+        !node.prefix &&
+        startsWithNoLookaheadToken(node.argument, forbidFunctionAndClass)
+      );
+    case "BindExpression":
+      return (
+        node.object &&
+        startsWithNoLookaheadToken(node.object, forbidFunctionAndClass)
+      );
+    case "SequenceExpression":
+      return startsWithNoLookaheadToken(
+        node.expressions[0],
+        forbidFunctionAndClass
+      );
+    default:
+      return false;
+  }
+}
+
+function getLeftMost(node) {
+  if (node.left) {
+    return getLeftMost(node.left);
+  } else {
+    return node;
+  }
+}
+
 module.exports = {
   getPrecedence,
   isExportDeclaration,
@@ -286,5 +341,6 @@ module.exports = {
   locEnd,
   setLocStart,
   setLocEnd,
-  htmlEscapeInsideAngleBracket
+  htmlEscapeInsideAngleBracket,
+  startsWithNoLookaheadToken
 };
diff --git a/tests/last_argument_expansion/__snapshots__/jsfmt.spec.js.snap b/tests/last_argument_expansion/__snapshots__/jsfmt.spec.js.snap
index d56fb130..c1cec4c0 100644
--- a/tests/last_argument_expansion/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/last_argument_expansion/__snapshots__/jsfmt.spec.js.snap
@@ -104,7 +104,7 @@ true
     }),
     require("postcss-url")({
       url: url =>
-        (url.startsWith("/") || /^[a-z]+:/.test(url) ? url : \`/static/\${url}\`)
+        url.startsWith("/") || /^[a-z]+:/.test(url) ? url : \`/static/\${url}\`
     })
   ]
 });
diff --git a/tests/ternaries/__snapshots__/jsfmt.spec.js.snap b/tests/ternaries/__snapshots__/jsfmt.spec.js.snap
index 8f8b6be6..054d4c38 100644
--- a/tests/ternaries/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/ternaries/__snapshots__/jsfmt.spec.js.snap
@@ -3,23 +3,55 @@
 exports[`parenthesis.js 1`] = `
 debug ? this.state.isVisible ? "partially visible" : "hidden" : null;
 debug ? this.state.isVisible && somethingComplex ? "partially visible" : "hidden" : null;
+
+a => a ? () => {a} : () => {a}
+a => a ? a : a
+a => a ? aasdasdasdasdasdasdaaasdasdasdasdasdasdasdasdasdasdasdasdasdaaaaaa : a
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 debug ? (this.state.isVisible ? "partially visible" : "hidden") : null;
 debug
   ? this.state.isVisible && somethingComplex ? "partially visible" : "hidden"
   : null;
 
+a =>
+  a
+    ? () => {
+        a;
+      }
+    : () => {
+        a;
+      };
+a => (a ? a : a);
+a =>
+  a ? aasdasdasdasdasdasdaaasdasdasdasdasdasdasdasdasdasdasdasdasdaaaaaa : a;
+
 `;
 
 exports[`parenthesis.js 2`] = `
 debug ? this.state.isVisible ? "partially visible" : "hidden" : null;
 debug ? this.state.isVisible && somethingComplex ? "partially visible" : "hidden" : null;
+
+a => a ? () => {a} : () => {a}
+a => a ? a : a
+a => a ? aasdasdasdasdasdasdaaasdasdasdasdasdasdasdasdasdasdasdasdasdaaaaaa : a
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 debug ? (this.state.isVisible ? "partially visible" : "hidden") : null;
 debug
     ? this.state.isVisible && somethingComplex ? "partially visible" : "hidden"
     : null;
 
+a =>
+    a
+        ? () => {
+              a;
+          }
+        : () => {
+              a;
+          };
+a => (a ? a : a);
+a =>
+    a ? aasdasdasdasdasdasdaaasdasdasdasdasdasdasdasdasdasdasdasdasdaaaaaa : a;
+
 `;
 
 exports[`test.js 1`] = `
diff --git a/tests/ternaries/parenthesis.js b/tests/ternaries/parenthesis.js
index 38e87106..c792c3c6 100644
--- a/tests/ternaries/parenthesis.js
+++ b/tests/ternaries/parenthesis.js
@@ -1,2 +1,6 @@
 debug ? this.state.isVisible ? "partially visible" : "hidden" : null;
 debug ? this.state.isVisible && somethingComplex ? "partially visible" : "hidden" : null;
+
+a => a ? () => {a} : () => {a}
+a => a ? a : a
+a => a ? aasdasdasdasdasdasdaaasdasdasdasdasdasdasdasdasdasdasdasdasdaaaaaa : a