diff --git a/src/class-names/index.js b/src/class-names/index.js
index 88dd419..83a15b1 100644
--- a/src/class-names/index.js
+++ b/src/class-names/index.js
@@ -47,6 +47,7 @@ export default async function getClassNames(
     let tailwindcss
     let browserslistModule
     let version
+    let featureFlags = { future: [], experimental: [] }
 
     const configPaths = (
       await glob(CONFIG_GLOB, {
@@ -75,6 +76,10 @@ export default async function getClassNames(
       browserslistModule = importFrom(tailwindBase, 'browserslist')
     } catch (_) {}
 
+    try {
+      featureFlags = importFrom(tailwindBase, './lib/featureFlags.js').default
+    } catch (_) {}
+
     const sepLocation = semver.gte(version, '0.99.0')
       ? ['separator']
       : ['options', 'separator']
@@ -152,6 +157,7 @@ export default async function getClassNames(
         tailwindcss,
         postcss,
       },
+      featureFlags,
     }
   }
 
diff --git a/src/lsp/providers/completionProvider.ts b/src/lsp/providers/completionProvider.ts
index ec93d44..795127c 100644
--- a/src/lsp/providers/completionProvider.ts
+++ b/src/lsp/providers/completionProvider.ts
@@ -28,6 +28,8 @@ import {
   getClassAttributeLexer,
   getComputedClassAttributeLexer,
 } from '../util/lexers'
+import { validateApply } from '../util/validateApply'
+import { flagEnabled } from '../util/flagEnabled'
 
 function completionsFromClassList(
   state: State,
@@ -193,16 +195,11 @@ function provideAtApplyCompletions(
       end: position,
     },
     (item) => {
-      // TODO: first line excludes all subtrees but there could _technically_ be
-      // valid apply-able class names in there. Will be correct in 99% of cases
-      if (item.kind === CompletionItemKind.Module) return false
-      let info = dlv(state.classNames.classNames, item.data)
-      return (
-        !Array.isArray(info) &&
-        info.__source === 'utilities' &&
-        info.__context.length === 0 &&
-        info.__pseudo.length === 0
-      )
+      if (item.kind === CompletionItemKind.Module) {
+        return flagEnabled(state, 'applyComplexClasses')
+      }
+      let validated = validateApply(state, item.data)
+      return validated !== null && validated.isApplyable === true
     }
   )
 }
diff --git a/src/lsp/providers/diagnostics/getInvalidApplyDiagnostics.ts b/src/lsp/providers/diagnostics/getInvalidApplyDiagnostics.ts
index e829b57..0f11ca4 100644
--- a/src/lsp/providers/diagnostics/getInvalidApplyDiagnostics.ts
+++ b/src/lsp/providers/diagnostics/getInvalidApplyDiagnostics.ts
@@ -3,6 +3,7 @@ import { InvalidApplyDiagnostic, DiagnosticKind } from './types'
 import { Settings, State } from '../../util/state'
 import { TextDocument, DiagnosticSeverity } from 'vscode-languageserver'
 import { validateApply } from '../../util/validateApply'
+import { flagEnabled } from '../../util/flagEnabled'
 
 export function getInvalidApplyDiagnostics(
   state: State,
@@ -11,6 +12,7 @@ export function getInvalidApplyDiagnostics(
 ): InvalidApplyDiagnostic[] {
   let severity = settings.lint.invalidApply
   if (severity === 'ignore') return []
+  if (flagEnabled(state, 'applyComplexClasses')) return []
 
   const classNames = findClassNamesInRange(document, undefined, 'css')
 
diff --git a/src/lsp/util/flagEnabled.ts b/src/lsp/util/flagEnabled.ts
new file mode 100644
index 0000000..51332c1
--- /dev/null
+++ b/src/lsp/util/flagEnabled.ts
@@ -0,0 +1,20 @@
+import { State } from './state'
+const dlv = require('dlv')
+
+export function flagEnabled(state: State, flag: string) {
+  if (state.featureFlags.future.includes(flag)) {
+    return (
+      state.config.future === 'all' ||
+      dlv(state.config, ['future', flag], false)
+    )
+  }
+
+  if (state.featureFlags.experimental.includes(flag)) {
+    return (
+      state.config.experimental === 'all' ||
+      dlv(state.config, ['experimental', flag], false)
+    )
+  }
+
+  return false
+}
diff --git a/src/lsp/util/state.ts b/src/lsp/util/state.ts
index 09a0200..47b976d 100644
--- a/src/lsp/util/state.ts
+++ b/src/lsp/util/state.ts
@@ -57,6 +57,7 @@ export type State = null | {
   variants?: string[]
   classNames?: ClassNames
   dependencies?: string[]
+  featureFlags?: { future: string[]; experimental: string[] }
   editor?: EditorState
   error?: Error
 }
diff --git a/src/lsp/util/validateApply.ts b/src/lsp/util/validateApply.ts
index 52f2b2c..5a17956 100644
--- a/src/lsp/util/validateApply.ts
+++ b/src/lsp/util/validateApply.ts
@@ -1,5 +1,6 @@
 import { State } from './state'
 import { getClassNameMeta } from './getClassNameMeta'
+import { flagEnabled } from './flagEnabled'
 
 export function validateApply(
   state: State,
@@ -8,6 +9,10 @@ export function validateApply(
   const meta = getClassNameMeta(state, classNameOrParts)
   if (!meta) return null
 
+  if (flagEnabled(state, 'applyComplexClasses')) {
+    return { isApplyable: true }
+  }
+
   const className = Array.isArray(classNameOrParts)
     ? classNameOrParts.join(state.separator)
     : classNameOrParts