I have never heard the term 'will had' used in standard English, however 'will have had' is a standard construct, used to describe something that will have happened by some future time. The precise timing of the future event is typically subject to some uncertainty.
"John will have had time to run his errands by the time we get there."
"Mary will have had the opportunity to review your resume carefully before your interview next Tuesday."
"They're very busy, but the mechanics should have had a chance to look at your car by the time you get back from your trip."
Note that the 'had' in each phrase isn't necessary at all, in fact it makes a bit of a constructive mess. You will likely encounter it only in spoken English.
So, why? Let's look at the last example.
In their mind, the speaker first translates 'have a chance' as a block of future time to be allocated to the subject project. So when they say "I will have a chance to look at your car...", they're thinking, say, 'two hours'. This verbal construct 'have a chance'(which they mentally use to represent 'two hours') then gets preserved as they start thinking of the owner returning and mentally switch to thinking of that block of time in the past tense "I had a chance to look at your car..." ('had a chance' = 'found two hours' - success!)
and so by the time their mental thought processes end up expressing an opinion, in the past tense, on the probability of a future event, with a finished car repair and a happy owner, it becomes
"I will have had a chance to look at your car..."
which makes more sense if you realize the speaker is thinking:
"I will have found two hours to look at your car..."
and that's how we end up with a common use, particularly in spoken English, for the future pluperfect:
"I will have [had some time, exactly when unspecified] to do [something]".
4I think these are "grammatically incorrect" instances that are only found in certain dialects. To my ear it sounds wrong, like you don't understand how to use future perfect properly. I would steer clear. – SteveES – 2017-05-23T13:41:21.240
@SteveES I agree with you, however, I sometimes stumble upon the term "Future pluperfect" and it seems not to let go of me. – SovereignSun – 2017-05-23T13:44:07.207
3I've never heard anything like "John will had run the race"; slightly more normal to me is "John will have had run the race", but usually I would just say "John will have run the race". But I see that the author is talking about certain dialects, not standard English. – stangdon – 2017-05-23T14:00:31.863
1"John will have had run the race" is (more or less) grammatical, but it is little different in meaning from "John will have run the race". So use the simpler form. – Andrew – 2017-05-23T14:14:13.353
1Just out of curiosity: why don't you try to acquire firstly the standard English?:) – Lucian Sava – 2017-05-23T14:33:36.233
@LucianSava My standard English is rather good I think. But, yes, I do improve it firstly. However, this isn't a question of acquiring but rather a question of interest. – SovereignSun – 2017-05-23T14:36:16.667
Oh!, I see, good point. Then I'm upvoting your questions. – Lucian Sava – 2017-05-23T14:41:45.283
These are isolated regionalisms. Unless a speaker has been exposed to them (e.g. though travel, say, or through having become acquainted, perhaps at university, with speakers from those parts of the country) they will not be readily understood. – Tᴚoɯɐuo – 2017-05-23T15:01:22.467
@stangdon I've definitely used it in my normal speech. Perhaps it's a southern accent but I sort of leave off the h sound in the sentence so it's more like .
John will 'ad run the race by the time we arrive
– MattCom – 2017-05-25T16:04:42.630@MattCom - Interesting; I wonder if it is a feature of Southern US English. I'll ask my wife and in-laws, who are from Louisiana. – stangdon – 2017-05-25T17:33:54.660