diff --git a/.eslintrc.js b/.eslintrc.js
index 4b2731d67..b8f76a4f4 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -21,7 +21,8 @@ module.exports = {
   rules: {
     'eslint-plugin/report-message-format': ['error', '^[A-Z`\'{].*\\.$'],
     'eslint-plugin/prefer-placeholders': 'error',
-    'eslint-plugin/consistent-output': 'error'
+    'eslint-plugin/consistent-output': 'error',
+    'no-mixed-operators': 'error'
   },
 
   overrides: [{
diff --git a/lib/rules/no-async-in-computed-properties.js b/lib/rules/no-async-in-computed-properties.js
index 3c4499382..393277287 100644
--- a/lib/rules/no-async-in-computed-properties.js
+++ b/lib/rules/no-async-in-computed-properties.js
@@ -27,7 +27,7 @@ const TIMED_FUNCTIONS = [
 ]
 
 function isTimedFunction (node) {
-  return (
+  return ((
     node.type === 'CallExpression' &&
     node.callee.type === 'Identifier' &&
     TIMED_FUNCTIONS.indexOf(node.callee.name) !== -1
@@ -38,7 +38,7 @@ function isTimedFunction (node) {
     node.callee.object.name === 'window' && (
       TIMED_FUNCTIONS.indexOf(node.callee.property.name) !== -1
     )
-  ) && node.arguments.length
+  )) && node.arguments.length
 }
 
 function isPromise (node) {
diff --git a/lib/rules/prop-name-casing.js b/lib/rules/prop-name-casing.js
index e70b24f0d..1a0ce185e 100644
--- a/lib/rules/prop-name-casing.js
+++ b/lib/rules/prop-name-casing.js
@@ -37,7 +37,7 @@ function create (context) {
 
   return utils.executeOnVue(context, (obj) => {
     const props = utils.getComponentProps(obj)
-      .filter(prop => prop.key && prop.key.type === 'Literal' || (prop.key.type === 'Identifier' && !prop.node.computed))
+      .filter(prop => prop.key && (prop.key.type === 'Literal' || (prop.key.type === 'Identifier' && !prop.node.computed)))
 
     for (const item of props) {
       const propName = item.key.type === 'Literal' ? item.key.value : item.key.name
diff --git a/lib/utils/indent-common.js b/lib/utils/indent-common.js
index c8c867250..e705e26d7 100644
--- a/lib/utils/indent-common.js
+++ b/lib/utils/indent-common.js
@@ -563,7 +563,7 @@ module.exports.defineVisitor = function create (context, tokenStore, defaultOpti
         } else {
           const baseOffsetInfo = offsets.get(offsetInfo.baseToken)
           if (baseOffsetInfo != null && baseOffsetInfo.expectedIndent != null && (i === 0 || !baseOffsetInfo.baseline)) {
-            expectedIndents.push(baseOffsetInfo.expectedIndent + offsetInfo.offset * options.indentSize)
+            expectedIndents.push(baseOffsetInfo.expectedIndent + (offsetInfo.offset * options.indentSize))
             if (baseOffsetInfo.baseline) {
               break
             }