Fix comment for call( // comment (#858)

This is a pretty exotic way to put a comment and it's been a long time since I have seen prettier output be as broken :)

Fixes #857

src/comments.js

@@ -173,6 +173,7 @@ function attach(comments, ast, text, options) {
         ) ||
         handleImportSpecifierComments(enclosingNode, comment) ||
         handleTemplateLiteralComments(enclosingNode, comment) ||
+        handleCallExpressionComments(precedingNode, enclosingNode, comment) ||
         handleClassComments(enclosingNode, comment)
       ) {
         // We're good
@@ -501,6 +502,16 @@ function handleImportSpecifierComments(enclosingNode, comment) {
   return false;
 }
 
+function handleCallExpressionComments(precedingNode, enclosingNode, comment) {
+  if (enclosingNode && enclosingNode.type === "CallExpression" &&
+      precedingNode && enclosingNode.callee === precedingNode &&
+      enclosingNode.arguments.length > 0) {
+    addLeadingComment(enclosingNode.arguments[0], comment);
+    return true;
+  }
+  return false;
+}
+
 function printComment(commentPath) {
   const comment = commentPath.getValue();
   comment.printed = true;

tests/comments/__snapshots__/jsfmt.spec.js.snap

@@ -52,6 +52,56 @@ exports[`blank.js 2`] = `
 "
 `;
 
+exports[`call_comment.js 1`] = `
+"render( // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+
+React.render( // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+render(
+  // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+
+React.render(
+  // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+"
+`;
+
+exports[`call_comment.js 2`] = `
+"render( // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+
+React.render( // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+render(
+  // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+
+React.render(
+  // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+"
+`;
+
 exports[`dangling.js 1`] = `
 "var x = {/* dangling */};
 var x = {

tests/comments/call_comment.js

@@ -0,0 +1,9 @@
+render( // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);
+
+React.render( // Warm any cache
+  <ChildUpdates renderAnchor={true} anchorClassOn={true} />,
+  container
+);