diff --git a/types/webpack/index.d.ts b/types/webpack/index.d.ts
index f5beb1dc63..40ce95bcad 100644
--- a/types/webpack/index.d.ts
+++ b/types/webpack/index.d.ts
@@ -538,12 +538,13 @@ declare namespace webpack {
 
     namespace Options {
         // tslint:disable-next-line:max-line-length
-        type Devtool = 'eval' | 'inline-source-map' | 'cheap-eval-source-map' | 'cheap-source-map' | 'cheap-module-eval-source-map' | 'cheap-module-source-map' | 'eval-source-map' | 'source-map' |
-            'nosources-source-map' | 'hidden-source-map' | 'nosources-source-map' | '@eval' | '@inline-source-map' | '@cheap-eval-source-map' | '@cheap-source-map' | '@cheap-module-eval-source-map' |
-            '@cheap-module-source-map' | '@eval-source-map' | '@source-map' | '@nosources-source-map' | '@hidden-source-map' | '@nosources-source-map' | '#eval' | '#inline-source-map' |
-            '#cheap-eval-source-map' | '#cheap-source-map' | '#cheap-module-eval-source-map' | '#cheap-module-source-map' | '#eval-source-map' | '#source-map' | '#nosources-source-map' |
-            '#hidden-source-map' | '#nosources-source-map' | '#@eval' | '#@inline-source-map' | '#@cheap-eval-source-map' | '#@cheap-source-map' | '#@cheap-module-eval-source-map' |
-            '#@cheap-module-source-map' | '#@eval-source-map' | '#@source-map' | '#@nosources-source-map' | '#@hidden-source-map' | '#@nosources-source-map' | boolean;
+        type Devtool = 'eval' | 'inline-source-map' | 'cheap-eval-source-map' | 'cheap-source-map' | 'cheap-module-eval-source-map' | 'cheap-module-source-map' | 'eval-source-map'
+            | 'source-map' | 'nosources-source-map' | 'hidden-source-map' | 'nosources-source-map' | 'inline-cheap-source-map' | 'inline-cheap-module-source-map' | '@eval'
+            | '@inline-source-map' | '@cheap-eval-source-map' | '@cheap-source-map' | '@cheap-module-eval-source-map' | '@cheap-module-source-map' | '@eval-source-map'
+            | '@source-map' | '@nosources-source-map' | '@hidden-source-map' | '@nosources-source-map' | '#eval' | '#inline-source-map' | '#cheap-eval-source-map'
+            | '#cheap-source-map' | '#cheap-module-eval-source-map' | '#cheap-module-source-map' | '#eval-source-map' | '#source-map' | '#nosources-source-map'
+            | '#hidden-source-map' | '#nosources-source-map' | '#@eval' | '#@inline-source-map' | '#@cheap-eval-source-map' | '#@cheap-source-map' | '#@cheap-module-eval-source-map'
+            | '#@cheap-module-source-map' | '#@eval-source-map' | '#@source-map' | '#@nosources-source-map' | '#@hidden-source-map' | '#@nosources-source-map' | boolean;
 
         interface Performance {
             /** This property allows webpack to control what files are used to calculate performance hints. */