From ad850ac49128dfcc292f0025c8c42f26bc26c735 Mon Sep 17 00:00:00 2001
From: Adam Wathan <adam.wathan@gmail.com>
Date: Fri, 8 May 2020 13:23:26 -0400
Subject: [PATCH 1/2] Throw if  contains a class

---
 __tests__/processPlugins.test.js | 19 +++++++++++++++++++
 src/util/processPlugins.js       | 15 +++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/__tests__/processPlugins.test.js b/__tests__/processPlugins.test.js
index 04ea56079e73..94d369ddec10 100644
--- a/__tests__/processPlugins.test.js
+++ b/__tests__/processPlugins.test.js
@@ -960,6 +960,25 @@ test('when important is a selector it is used to scope utilities instead of addi
     `)
 })
 
+test('when important contains a class an error is thrown', () => {
+  expect(() => {
+    processPlugins(
+      [
+        function({ addUtilities }) {
+          addUtilities({
+            '.rotate-90': {
+              transform: 'rotate(90deg)',
+            },
+          })
+        },
+      ],
+      makeConfig({
+        important: '#app .project',
+      })
+    )
+  }).toThrow()
+})
+
 test('when important is a selector it scopes all selectors in a rule, even though defining utilities like this is stupid', () => {
   const { utilities } = processPlugins(
     [
diff --git a/src/util/processPlugins.js b/src/util/processPlugins.js
index bdee55478cda..deb11b90e4cf 100644
--- a/src/util/processPlugins.js
+++ b/src/util/processPlugins.js
@@ -9,6 +9,7 @@ import parseObjectStyles from '../util/parseObjectStyles'
 import prefixSelector from '../util/prefixSelector'
 import wrapWithVariants from '../util/wrapWithVariants'
 import increaseSpecificity from '../util/increaseSpecificity'
+import selectorParser from 'postcss-selector-parser'
 
 function parseStyles(styles) {
   if (!Array.isArray(styles)) {
@@ -18,6 +19,14 @@ function parseStyles(styles) {
   return _.flatMap(styles, style => (style instanceof Node ? style : parseObjectStyles(style)))
 }
 
+function containsClass(value) {
+  return selectorParser(selectors => {
+    let classFound = false
+    selectors.walkClasses(() => (classFound = true))
+    return classFound
+  }).transformSync(value)
+}
+
 export default function(plugins, config) {
   const pluginBaseStyles = []
   const pluginComponents = []
@@ -86,6 +95,12 @@ export default function(plugins, config) {
             if (config.important === true) {
               rule.walkDecls(decl => (decl.important = true))
             } else if (typeof config.important === 'string') {
+              if (containsClass(config.important)) {
+                throw rule.error(
+                  `Classes are not allowed when using the \`important\` option with a string argument. Please use an ID instead.`
+                )
+              }
+
               rule.selectors = rule.selectors.map(selector => {
                 return increaseSpecificity(config.important, selector)
               })

From a6d434375be47d717ae90b506c7924f5d2089210 Mon Sep 17 00:00:00 2001
From: Adam Wathan <adam.wathan@gmail.com>
Date: Fri, 8 May 2020 13:26:50 -0400
Subject: [PATCH 2/2] 1.4.6

---
 package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package.json b/package.json
index 321e7f7751f0..116fceb13e66 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "tailwindcss",
-  "version": "1.4.5",
+  "version": "1.4.6",
   "description": "A utility-first CSS framework for rapidly building custom user interfaces.",
   "license": "MIT",
   "main": "lib/index.js",