From 5f88a9314fd1a1e8831acfa1f4ffb585584df66e Mon Sep 17 00:00:00 2001
From: fisker Cheung <lionkay@gmail.com>
Date: Mon, 2 Feb 2026 20:15:31 +0800
Subject: [PATCH] Fix comments not printed error in debugger statement (#18840)

---
 changelog_unreleased/javascript/18840.md      | 14 ++++
 src/language-js/loc.js                        |  4 +
 src/language-js/print/ignored.js              |  1 +
 .../no-semi/__snapshots__/format.test.js.snap | 79 +++++++++++++++++++
 tests/format/js/no-semi/debugger-statement.js | 14 ++++
 5 files changed, 112 insertions(+)
 create mode 100644 changelog_unreleased/javascript/18840.md
 create mode 100644 tests/format/js/no-semi/debugger-statement.js

diff --git a/changelog_unreleased/javascript/18840.md b/changelog_unreleased/javascript/18840.md
new file mode 100644
index 000000000..8b423d110
--- /dev/null
+++ b/changelog_unreleased/javascript/18840.md
@@ -0,0 +1,14 @@
+#### Fix "comment not printed" error in debugger statement (#18840 by @fisker)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+debugger // Comment
+;
+
+// Prettier stable
+Error: Comment "comment" was not printed. Please report this error!
+
+// Prettier main
+debugger; // Comment
+```
diff --git a/src/language-js/loc.js b/src/language-js/loc.js
index 00ed80959..698c8cd8a 100644
--- a/src/language-js/loc.js
+++ b/src/language-js/loc.js
@@ -34,6 +34,10 @@ function locEnd(node) {
           (node.type === "BreakStatement" ? "break".length : "continue".length);
   }
 
+  if (node.type === "DebuggerStatement") {
+    return locStart(node) + "debugger".length;
+  }
+
   if (node.type === "VariableDeclaration") {
     const lastDeclaration = node.declarations.at(-1);
     return locEnd(lastDeclaration);
diff --git a/src/language-js/print/ignored.js b/src/language-js/print/ignored.js
index 19565493d..4f314c6fc 100644
--- a/src/language-js/print/ignored.js
+++ b/src/language-js/print/ignored.js
@@ -11,6 +11,7 @@ function printIgnored(path, options /* , print*/) {
     options.semi &&
     (node.type === "BreakStatement" ||
       node.type === "ContinueStatement" ||
+      node.type === "DebuggerStatement" ||
       node.type === "VariableDeclaration" ||
       ((node.type === "ExpressionStatement" ||
         node.type === "Directive" ||
diff --git a/tests/format/js/no-semi/__snapshots__/format.test.js.snap b/tests/format/js/no-semi/__snapshots__/format.test.js.snap
index 5a297c469..151cee4cb 100644
--- a/tests/format/js/no-semi/__snapshots__/format.test.js.snap
+++ b/tests/format/js/no-semi/__snapshots__/format.test.js.snap
@@ -616,6 +616,85 @@ x;
 ================================================================================
 `;
 
+exports[`debugger-statement.js - {"semi":false} format 1`] = `
+====================================options=====================================
+parsers: ["babel", "typescript", "flow"]
+semi: false
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+debugger
+
+// 11
+;[]
+
+debugger
+
+// 21
+;foo
+
+// prettier-ignore
+debugger
+
+;[]
+
+=====================================output=====================================
+debugger
+
+// 11
+;[]
+
+debugger
+
+// 21
+foo
+
+// prettier-ignore
+debugger
+
+;[]
+
+================================================================================
+`;
+
+exports[`debugger-statement.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "typescript", "flow"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+debugger
+
+// 11
+;[]
+
+debugger
+
+// 21
+;foo
+
+// prettier-ignore
+debugger
+
+;[]
+
+=====================================output=====================================
+debugger;
+
+// 11
+[];
+
+debugger;
+
+// 21
+foo;
+
+// prettier-ignore
+debugger;
+
+[];
+
+================================================================================
+`;
+
 exports[`imports.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "typescript", "flow"]
diff --git a/tests/format/js/no-semi/debugger-statement.js b/tests/format/js/no-semi/debugger-statement.js
new file mode 100644
index 000000000..c88c78687
--- /dev/null
+++ b/tests/format/js/no-semi/debugger-statement.js
@@ -0,0 +1,14 @@
+debugger
+
+// 11
+;[]
+
+debugger
+
+// 21
+;foo
+
+// prettier-ignore
+debugger
+
+;[]