From 4be5d9d0820980016ea45c5ee8d17a6846ea1e43 Mon Sep 17 00:00:00 2001
From: Brad Cornes <bradlc41@gmail.com>
Date: Fri, 25 Feb 2022 13:20:02 +0000
Subject: [PATCH] Detect conflicting multi-rule classes (#498)

---
 .../diagnostics/getCssConflictDiagnostics.ts  | 54 +++++++++----------
 1 file changed, 25 insertions(+), 29 deletions(-)

diff --git a/packages/tailwindcss-language-service/src/diagnostics/getCssConflictDiagnostics.ts b/packages/tailwindcss-language-service/src/diagnostics/getCssConflictDiagnostics.ts
index c061ec4..4459d24 100644
--- a/packages/tailwindcss-language-service/src/diagnostics/getCssConflictDiagnostics.ts
+++ b/packages/tailwindcss-language-service/src/diagnostics/getCssConflictDiagnostics.ts
@@ -25,42 +25,40 @@ export async function getCssConflictDiagnostics(
     classNames.forEach((className, index) => {
       if (state.jit) {
         let { rules } = jit.generateRules(state, [className.className])
-        if (rules.length !== 1) {
+        if (rules.length === 0) {
           return
         }
-        let rule = rules[0]
-        let context: string[]
-        let properties = []
-        rule.walkDecls(({ prop }) => {
-          properties.push(prop)
+
+        let info: Array<{ context: string[]; properties: string[] }> = rules.map((rule) => {
+          let properties: string[] = []
+          rule.walkDecls(({ prop }) => {
+            properties.push(prop)
+          })
+          let context = jit.getRuleContext(state, rule, className.className)
+          return { context, properties }
         })
 
         let otherClassNames = classNames.filter((_className, i) => i !== index)
 
         let conflictingClassNames = otherClassNames.filter((otherClassName) => {
-          let { rules } = jit.generateRules(state, [otherClassName.className])
-          if (rules.length !== 1) {
+          let { rules: otherRules } = jit.generateRules(state, [otherClassName.className])
+          if (otherRules.length !== rules.length) {
             return false
           }
 
-          let otherRule = rules[0]
-
-          let otherProperties = []
-          otherRule.walkDecls(({ prop }) => {
-            otherProperties.push(prop)
-          })
-
-          if (!equal(properties, otherProperties)) {
-            return false
-          }
-
-          if (!context) {
-            context = jit.getRuleContext(state, rule, className.className)
-          }
-          let otherContext = jit.getRuleContext(state, otherRule, otherClassName.className)
-
-          if (!equal(context, otherContext)) {
-            return false
+          for (let i = 0; i < otherRules.length; i++) {
+            let rule = otherRules[i]
+            let properties: string[] = []
+            rule.walkDecls(({ prop }) => {
+              properties.push(prop)
+            })
+            if (!equal(info[i].properties, properties)) {
+              return false
+            }
+            let context = jit.getRuleContext(state, rule, otherClassName.className)
+            if (!equal(info[i].context, context)) {
+              return false
+            }
           }
 
           return true
@@ -77,9 +75,7 @@ export async function getCssConflictDiagnostics(
             severity === 'error'
               ? 1 /* DiagnosticSeverity.Error */
               : 2 /* DiagnosticSeverity.Warning */,
-          message: `'${className.className}' applies the same CSS ${
-            properties.length === 1 ? 'property' : 'properties'
-          } as ${joinWithAnd(
+          message: `'${className.className}' applies the same CSS properties as ${joinWithAnd(
             conflictingClassNames.map(
               (conflictingClassName) => `'${conflictingClassName.className}'`
             )