diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l
index 4c28b976e..462b3b602 100644
--- a/src/libexpr/lexer.l
+++ b/src/libexpr/lexer.l
@@ -198,7 +198,7 @@ or          { return OR_KW; }
                    (...|\$[^\{\"\\]|\\.|\$\\.)+ would have triggered.
                    This is technically invalid, but we leave the problem to the
                    parser who fails with exact location. */
-                return STR;
+                return EOF;
               }
 
 \'\'(\ *\n)?     { PUSH_STATE(IND_STRING); return IND_STRING_OPEN; }
diff --git a/tests/lang/parse-fail-eof-in-string.nix b/tests/lang/parse-fail-eof-in-string.nix
new file mode 100644
index 000000000..19775d2ec
--- /dev/null
+++ b/tests/lang/parse-fail-eof-in-string.nix
@@ -0,0 +1,3 @@
+# https://github.com/NixOS/nix/issues/6562
+# Note that this file must not end with a newline.
+a 1"$
\ No newline at end of file