whether there's a massacre in Tiananmen Square in the morning of June 4 is a literal dispute in my opinion. Hou Dejian (a famous Taiwan singer quisled to mainland in 1983, attended 1989 demonstration on Tiananmen Square, was exiled back to Taiwan after June 4 and was sentenced 6 monthes in prison as a stowaway by Taiwan judiciary authority), he said, after June 4 on a video(The Gate of Heavenly Peace), he saw no one killed in Tiananmen Square in the morning at June 4. I trust him.
but, Tiananmen Massacre was not simply confined in the place of the square or the time of the morning. the troops shot their way to Tiananmen from Muxidi or some other entrances after June 3 against the civilians who blocked their way. the troops cleared up the square with no casulty in the morning of June 4, but they did clear Beijing with casulties. in the day time of June 4, civilians heard the killing of the troops, they called for a rally to confront the armies, then there started the Tiananmen Massacre. the furiousest fights happened after the morning of June 4, and lasted for one week until Changanjie Street was full of tanks and soldiers.
Beijing map of main streets
Tiananmen Massacre or June 4 Massacre are two symbolistic titles, as well Tiananmen Students Demonstration, they demonstrated from Xueyuanlu street to Changanjie street to Tiananmen square, why did not we name it XCT demonstration? i did not see any evidence to say there's no one died in Tiananmen square after the morning of June 4. I believe it's very clear that there were casulties on the picture, and i do know this place very well, it's Changanjie street's east part, where a white mini bus was burning is Nanchizi, on the back of the troop lines and behind the trees is Tiananmen Square(the upper region of the picture). they took the picture absolutely after the morning June 4 ( because as we can see the square had been cleared up ), maybe June 5 or later, i do not know. but do we need to name the event Changanjie East Part Massacre or June 5 Massacre, or .... what? 
Before we can see the secret archives of CCP, we can say at least more than 300 died, more than 7000 injured, and i also can say a bigger number of casulties wont surprise me because i know the government concealed the truth.