fix code, test and style

Author: rhurling

__tests__/applyAtRule.test.js

@@ -195,22 +195,23 @@ test('you can apply utility classes that do not actually exist as long as they w
 
 test('you can apply utility classes without using the given prefix', () => {
   const input = `
-    .foo { @apply .mt-4; }
+    .foo { @apply .tw-mt-4 .mb-4; }
   `
 
   const expected = `
-    .prefix-foo { margin-top: 1rem; }
+    .foo { margin-top: 1rem; margin-bottom: 1rem; }
   `
 
   const config = {
     ...defaultConfig,
     options: {
       ...defaultConfig.options,
-      prefix: 'prefix-',
+      prefix: 'tw-',
     },
+    experiments: { shadowLookup: true },
   }
 
-  return run(input, config).then(result => {
+  return run(input, config, generateUtilities(config, [])).then(result => {
     expect(result.css).toEqual(expected)
     expect(result.warnings().length).toBe(0)
   })

src/lib/substituteClassApplyAtRules.js

@@ -45,13 +45,13 @@ function findClass(classToApply, classTable, shadowLookup, prefix, onError) {
 
           return findClass(classToApply, shadowLookup, {}, '', onError)
         }
+      } else {
+        // prettier-ignore
+        throw onError(`\`@apply\` cannot be used with \`${classToApply}\` because \`${classToApply}\` either cannot be found, or it's actual definition includes a pseudo-selector like :hover, :active, etc. If you're sure that \`${classToApply}\` exists, make sure that any \`@import\` statements are being properly processed *before* Tailwind CSS sees your CSS, as \`@apply\` can only be used for classes in the same CSS tree.`)
       }
-      
-      // prettier-ignore
-      throw onError(`\`@apply\` cannot be used with \`${classToApply}\` because \`${classToApply}\` either cannot be found, or it's actual definition includes a pseudo-selector like :hover, :active, etc. If you're sure that \`${classToApply}\` exists, make sure that any \`@import\` statements are being properly processed *before* Tailwind CSS sees your CSS, as \`@apply\` can only be used for classes in the same CSS tree.`)
+    } else {
+      return findClass(classToApply, shadowLookup, {}, prefix, onError)
     }
-
-    return findClass(classToApply, shadowLookup, {}, prefix, onError)
   }
 
   if (matches.length > 1) {
@@ -94,9 +94,15 @@ export default function(config, generatedUtilities) {
         const decls = _(classes)
           .reject(cssClass => cssClass === '!important')
           .flatMap(cssClass => {
-            return findClass(normalizeClassName(cssClass), classLookup, shadowLookup, config.options.prefix, message => {
-              return atRule.error(message)
-            })
+            return findClass(
+              normalizeClassName(cssClass),
+              classLookup,
+              shadowLookup,
+              config.options.prefix,
+              message => {
+                return atRule.error(message)
+              }
+            )
           })
           .value()