Problem

In call_oc_method() located in src/vim9class.c, get_func_arguments() is called at line 3100 to parse and evaluate function arguments into argvars[]. When get_func_arguments() fails, it may have already populated argvars[0..argcount-1] with evaluated arguments that own allocated memory (e.g., strings, lists, dicts).

The function returns FAIL immediately without cleaning up these arguments:

int ret = get_func_arguments(&argp, evalarg, 0, argvars, &argcount, FALSE);
if (ret == FAIL)
    return FAIL;       // argvars[0..argcount-1] leaked

The cleanup loop at lines 3126-3127 is only reached on the success path:

for (int idx = 0; idx < argcount; ++idx)
    clear_tv(&argvars[idx]);

Other callers of get_func_arguments() (e.g., get_func_tv() in src/userfunc.c:2209-2210) correctly clean up argvars on both success and failure paths.

Solution

Clean up the already-parsed arguments before returning FAIL, matching the pattern used in get_func_tv(). The fix is included in the commit.