The copies of a base string one Str.repeat may ask for. eval appends one copy at a time, so the differential run costs quadratic time in it: one declaration repeating a caller's string emits in 7 s at this count, 17 s at four times it and 198 s at sixteen times it.

The elements one Arr.range may ask for. What the ceiling buys is what maxRepeat buys -- every vector of the differential run holds the array whole -- but the cost is linear in the count rather than quadratic: one declaration ranging over this count adds half a second to a 1.7 s run, where a declaration repeating a caller's string at the same count costs 7 s. The number is maxRepeat again so that there is one ceiling to know rather than two, not because this is where ranging starts to hurt.

What the syntax says about the value of an Int53 expression. none at an end is the checker declining to say, never a claim that the value is unbounded there.

Everything either branch can produce.

Ranges the program text has pinned to a name. A binder that shadows one drops it rather than letting the body read through to the outer value.

What the syntax says about an Int53 expression. A length is never negative and has no upper bound the text can name; Int53.div and % are read as unknown, which only ever refuses more.

How many copies of a base string an expression can hold, once every Str.repeat inside it has multiplied. A name stands for whatever the caller passes, which is one copy of itself.

Which of the two a refusal is about, so that it can name the operation the author wrote and the clamp that would fix it.

How many times the text says a traversal over this array runs. none is the checker declining to say, and that is the ordinary answer: an array a caller passes is as long as the vector generator made it, which is what bounds a body that repeats per element. An Arr.range is the exception -- its length is in the text -- so it is the one traversal whose body has to be counted against the ceiling as many times as it runs.

What one traversal multiplies the size its body asks for by.

The first result in a body whose size the text does not bound, which of the two it is, and how far past the bound it reaches when the text does bound it.

factor is how many times the traversals above this point can run it. A body inside a traversal over an Arr.range 64 builds sixty-four of whatever it builds, so what is measured against the ceiling is the product rather than one result.

What the refusal says about one result the text does not bound. Str.padStart is named alongside Str.repeat because that is the spelling a user wrote; the repeat only appears once it expands.

Every result a program can reach whose size a value decides, bounded by the text. The parameters start unknown, which is what makes a size a caller chooses the thing this refuses.