--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -1260,8 +1260,7 @@ func_clear(ufunc_T *fp, int force)
     // clear this function
     func_clear_items(fp);
     funccal_unref(fp->uf_scoped, fp, force);
-    if ((fp->uf_flags & FC_COPY) == 0)
-	clear_def_function(fp);
+    unlink_def_function(fp);
 }
 
 /*
@@ -1307,75 +1306,98 @@ func_clear_free(ufunc_T *fp, int force)
 /*
  * Copy already defined function "lambda" to a new function with name "global".
  * This is for when a compiled function defines a global function.
- * Caller should take care of adding a partial for a closure.
  */
-    ufunc_T *
-copy_func(char_u *lambda, char_u *global)
+    int
+copy_func(char_u *lambda, char_u *global, ectx_T *ectx)
 {
     ufunc_T *ufunc = find_func_even_dead(lambda, TRUE, NULL);
     ufunc_T *fp = NULL;
 
     if (ufunc == NULL)
+    {
 	semsg(_(e_lambda_function_not_found_str), lambda);
-    else
+	return FAIL;
+    }
+
+    // TODO: handle ! to overwrite
+    fp = find_func(global, TRUE, NULL);
+    if (fp != NULL)
     {
-	// TODO: handle ! to overwrite
-	fp = find_func(global, TRUE, NULL);
-	if (fp != NULL)
-	{
-	    semsg(_(e_funcexts), global);
-	    return NULL;
-	}
-
-	fp = alloc_clear(offsetof(ufunc_T, uf_name) + STRLEN(global) + 1);
-	if (fp == NULL)
-	    return NULL;
-
-	fp->uf_varargs = ufunc->uf_varargs;
-	fp->uf_flags = (ufunc->uf_flags & ~FC_VIM9) | FC_COPY;
-	fp->uf_def_status = ufunc->uf_def_status;
-	fp->uf_dfunc_idx = ufunc->uf_dfunc_idx;
-	if (ga_copy_strings(&ufunc->uf_args, &fp->uf_args) == FAIL
-		|| ga_copy_strings(&ufunc->uf_def_args, &fp->uf_def_args)
-									== FAIL
-		|| ga_copy_strings(&ufunc->uf_lines, &fp->uf_lines) == FAIL)
+	semsg(_(e_funcexts), global);
+	return FAIL;
+    }
+
+    fp = alloc_clear(offsetof(ufunc_T, uf_name) + STRLEN(global) + 1);
+    if (fp == NULL)
+	return FAIL;
+
+    fp->uf_varargs = ufunc->uf_varargs;
+    fp->uf_flags = (ufunc->uf_flags & ~FC_VIM9) | FC_COPY;
+    fp->uf_def_status = ufunc->uf_def_status;
+    fp->uf_dfunc_idx = ufunc->uf_dfunc_idx;
+    if (ga_copy_strings(&ufunc->uf_args, &fp->uf_args) == FAIL
+	    || ga_copy_strings(&ufunc->uf_def_args, &fp->uf_def_args)
+								    == FAIL
+	    || ga_copy_strings(&ufunc->uf_lines, &fp->uf_lines) == FAIL)
+	goto failed;
+
+    fp->uf_name_exp = ufunc->uf_name_exp == NULL ? NULL
+					 : vim_strsave(ufunc->uf_name_exp);
+    if (ufunc->uf_arg_types != NULL)
+    {
+	fp->uf_arg_types = ALLOC_MULT(type_T *, fp->uf_args.ga_len);
+	if (fp->uf_arg_types == NULL)
 	    goto failed;
-
-	fp->uf_name_exp = ufunc->uf_name_exp == NULL ? NULL
-					     : vim_strsave(ufunc->uf_name_exp);
-	if (ufunc->uf_arg_types != NULL)
-	{
-	    fp->uf_arg_types = ALLOC_MULT(type_T *, fp->uf_args.ga_len);
-	    if (fp->uf_arg_types == NULL)
-		goto failed;
-	    mch_memmove(fp->uf_arg_types, ufunc->uf_arg_types,
-					sizeof(type_T *) * fp->uf_args.ga_len);
-	}
-	if (ufunc->uf_def_arg_idx != NULL)
-	{
-	    fp->uf_def_arg_idx = ALLOC_MULT(int, fp->uf_def_args.ga_len + 1);
-	    if (fp->uf_def_arg_idx == NULL)
-		goto failed;
-	    mch_memmove(fp->uf_def_arg_idx, ufunc->uf_def_arg_idx,
-				     sizeof(int) * fp->uf_def_args.ga_len + 1);
-	}
-	if (ufunc->uf_va_name != NULL)
-	{
-	    fp->uf_va_name = vim_strsave(ufunc->uf_va_name);
-	    if (fp->uf_va_name == NULL)
-		goto failed;
-	}
-	fp->uf_ret_type = ufunc->uf_ret_type;
-
-	fp->uf_refcount = 1;
-	STRCPY(fp->uf_name, global);
-	hash_add(&func_hashtab, UF2HIKEY(fp));
+	mch_memmove(fp->uf_arg_types, ufunc->uf_arg_types,
+				    sizeof(type_T *) * fp->uf_args.ga_len);
+    }
+    if (ufunc->uf_def_arg_idx != NULL)
+    {
+	fp->uf_def_arg_idx = ALLOC_MULT(int, fp->uf_def_args.ga_len + 1);
+	if (fp->uf_def_arg_idx == NULL)
+	    goto failed;
+	mch_memmove(fp->uf_def_arg_idx, ufunc->uf_def_arg_idx,
+				 sizeof(int) * fp->uf_def_args.ga_len + 1);
+    }
+    if (ufunc->uf_va_name != NULL)
+    {
+	fp->uf_va_name = vim_strsave(ufunc->uf_va_name);
+	if (fp->uf_va_name == NULL)
+	    goto failed;
     }
-    return fp;
+    fp->uf_ret_type = ufunc->uf_ret_type;
+
+    fp->uf_refcount = 1;
+    STRCPY(fp->uf_name, global);
+    hash_add(&func_hashtab, UF2HIKEY(fp));
+
+    // the referenced dfunc_T is now used one more time
+    link_def_function(fp);
+
+    // Create a partial to store the context of the function, if not done
+    // already.
+    if ((ufunc->uf_flags & FC_CLOSURE) && ufunc->uf_partial == NULL)
+    {
+	partial_T   *pt = ALLOC_CLEAR_ONE(partial_T);
+
+	if (pt == NULL)
+	    goto failed;
+	if (fill_partial_and_closure(pt, ufunc, ectx) == FAIL)
+	    goto failed;
+	ufunc->uf_partial = pt;
+	--pt->pt_refcount;  // not referenced here yet
+    }
+    if (ufunc->uf_partial != NULL)
+    {
+	fp->uf_partial = ufunc->uf_partial;
+	++fp->uf_partial->pt_refcount;
+    }
+
+    return OK;
 
 failed:
     func_clear_free(fp, TRUE);
-    return NULL;
+    return FAIL;
 }
 
 static int	funcdepth = 0;
@@ -3515,7 +3537,7 @@ define_function(exarg_T *eap, char_u *na
 		fp->uf_profiling = FALSE;
 		fp->uf_prof_initialized = FALSE;
 #endif
-		clear_def_function(fp);
+		unlink_def_function(fp);
 	    }
 	}
     }