He has not done so, and I gather he is stonewalling reporters on the question.
In the meeting with Ferguson, there was an accusation of stonewalling him.
On Fox News he said he did not believe the CIA was stonewalling his committee, as others had alleged.
By stonewalling, Apple is needlessly making things worse for itself.
Old English stanwalle (n.); see stone (n.) + wall (n.). As nickname of Confederate General Thomas J. Jackson (1824-1863), bestowed 1861 on the occasion of the First Battle of Bull Run, supposedly by Gen. Bernard Bee, urging his brigade to rally around Jackson, who was "standing like a stone wall." Bee was killed in the battle; the account of the nickname appeared in Southern newspapers within four days of the battle.
On the face of it this account has no character of authenticity, and the words ascribed to Bee smack less of the battlefield than of the editorial sanctum. ... It seems inherently probable that something was said by somebody, during or immediately after the battle, that likened Jackson or his men or both to a stone wall. [R.M. Johnston, "Bull Run: Its Strategy and Tactics," Boston, 1913]
"to obstruct," 1914, from metaphoric use of stone wall for "act of obstruction" (1876). Related: Stonewalled; stonewalling.
An intoxicated or stuporous person: mumbles a stoner performance that's sidesplittingly funny/ It's different than it was in the '60s because it's not just your obvious stoner types. It's the jocks and the A-plus students. It's just about everybody (1960s+)