[Rd] unexpected behaviour in lm() (PR#3657)

[Peter Dalgaard BSA]

ottk at bms.com writes:

> > lm(c(1:10) ~ c(1:10))
> 
> Call:
> lm(formula = c(1:10) ~ c(1:10))
> 
> Coefficients:
> (Intercept)  
>         5.5  

Unexpected: yes, bug: no.

Thing is that the lm logic removes the resonse from the set of
predictors. This is to support stuff like "y ~ .", I believe.

You get the same effect from

> x <- c(1:10)
> lm(x~x)

Call:
lm(formula = x ~ x)

Coefficients:
(Intercept)
        5.5


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
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