From 27f0de62e6281c28043be38ef051818c9edc15cd Mon Sep 17 00:00:00 2001
From: Milos Djermanovic <milos.djermanovic@gmail.com>
Date: Tue, 6 Oct 2020 15:11:43 +0200
Subject: [PATCH] Fix: account for linebreaks before postfix `++`/`--` in
 no-extra-parens (#13731)

---
 lib/rules/no-extra-parens.js       | 17 ++++++++++++++++-
 tests/lib/rules/no-extra-parens.js | 21 +++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/lib/rules/no-extra-parens.js b/lib/rules/no-extra-parens.js
index e9d394c616a..7afe7625dfc 100644
--- a/lib/rules/no-extra-parens.js
+++ b/lib/rules/no-extra-parens.js
@@ -1109,7 +1109,22 @@ module.exports = {
             },
 
             UnaryExpression: checkArgumentWithPrecedence,
-            UpdateExpression: checkArgumentWithPrecedence,
+            UpdateExpression(node) {
+                if (node.prefix) {
+                    checkArgumentWithPrecedence(node);
+                } else {
+                    const { argument } = node;
+                    const operatorToken = sourceCode.getLastToken(node);
+
+                    if (argument.loc.end.line === operatorToken.loc.start.line) {
+                        checkArgumentWithPrecedence(node);
+                    } else {
+                        if (hasDoubleExcessParens(argument)) {
+                            report(argument);
+                        }
+                    }
+                }
+            },
             AwaitExpression: checkArgumentWithPrecedence,
 
             VariableDeclarator(node) {
diff --git a/tests/lib/rules/no-extra-parens.js b/tests/lib/rules/no-extra-parens.js
index befdcda5a1c..c0d0387ec74 100644
--- a/tests/lib/rules/no-extra-parens.js
+++ b/tests/lib/rules/no-extra-parens.js
@@ -363,6 +363,15 @@ ruleTester.run("no-extra-parens", rule, {
             "}"
         ].join("\n"),
 
+        // linebreaks before postfix update operators are not allowed
+        "(a\n)++",
+        "(a\n)--",
+        "(a\n\n)++",
+        "(a.b\n)--",
+        "(a\n.b\n)++",
+        "(a[\nb\n]\n)--",
+        "(a[b]\n\n)++",
+
         // async/await
         "async function a() { await (a + b) }",
         "async function a() { await (a + await b) }",
@@ -755,6 +764,18 @@ ruleTester.run("no-extra-parens", rule, {
         invalid("+((bar-foo))", "+(bar-foo)", "BinaryExpression"),
         invalid("++(foo)", "++foo", "Identifier"),
         invalid("--(foo)", "--foo", "Identifier"),
+        invalid("++\n(foo)", "++\nfoo", "Identifier"),
+        invalid("--\n(foo)", "--\nfoo", "Identifier"),
+        invalid("++(\nfoo)", "++\nfoo", "Identifier"),
+        invalid("--(\nfoo)", "--\nfoo", "Identifier"),
+        invalid("(foo)++", "foo++", "Identifier"),
+        invalid("(foo)--", "foo--", "Identifier"),
+        invalid("((foo)\n)++", "(foo\n)++", "Identifier"),
+        invalid("((foo\n))--", "(foo\n)--", "Identifier"),
+        invalid("((foo\n)\n)++", "(foo\n\n)++", "Identifier"),
+        invalid("(a\n.b)--", "a\n.b--", "MemberExpression"),
+        invalid("(a.\nb)++", "a.\nb++", "MemberExpression"),
+        invalid("(a\n[\nb\n])--", "a\n[\nb\n]--", "MemberExpression"),
         invalid("(a || b) ? c : d", "a || b ? c : d", "LogicalExpression"),
         invalid("a ? (b = c) : d", "a ? b = c : d", "AssignmentExpression"),
         invalid("a ? b : (c = d)", "a ? b : c = d", "AssignmentExpression"),