diff --git a/js/prose-decl.js b/js/prose-decl.js
index a866da5..d51eb14 100644
--- a/js/prose-decl.js
+++ b/js/prose-decl.js
@@ -7,7 +7,7 @@ const SPECIFIER_CONFLICTS = [
     ['class', 'struct', 'union', 'enum', 'void', 'complex', '_Atomic()', 'bool'],
     ['class', 'struct', 'union', 'enum', 'signed', 'unsigned', 'float', 'double', 'void',
         '_Atomic()'],
-    ['class', 'struct', 'union', 'enum', 'signed', 'unsigned', 'complex'],
+    ['class', 'struct', 'union', 'enum', 'signed', 'unsigned', 'typedef-name', 'bool', 'complex'],
     ['int', 'complex'],
     ['char', 'short', 'long', 'void', 'bool', 'complex'],
     ['int', 'float', 'double', 'void', '_Atomic()'],
diff --git a/test/test.js b/test/test.js
index 1e3e75c..6ee872e 100644
--- a/test/test.js
+++ b/test/test.js
@@ -178,4 +178,12 @@ describe('Examples', function () {
             assert.deepEqual(actual, expected);
         });
     });
+
+    code = 'signed bool';
+    describe(code, function () {
+        it('throws because "signed" and "bool" conflict', function () {
+            assert.throws(() => codeToProse(code),
+                {message: 'Conflicting specifiers signed and bool'});
+        });
+    });
 });