String interpolation with terminal dot breaking 1.2 -> 1.3

[matbesancon]

This is more a difference than a bug, but definitely breaking:

1.2:

julia> var = 3
3
julia> println("Hello from var $var.")
Hello from var 3.

1.3-rc1:

julia> var = 3
3

julia> println("Hello from var $var.")
ERROR: syntax: unexpected ")"
Stacktrace:
 [1] top-level scope at REPL[1]:0

From HISTORY.md:

Non-parenthesized interpolated variables in strings, e.g. "$x", must be followed by a character that will never be an allowed identifier character (currently operators, space/control characters, or common punctuation characters) (#25231).

So this was sort of warned but not erroring before 1.3

Edit

Going even deeper, the error does not happen with 1-char variable identifiers:

julia> x = 1
1

julia> "$x."
"1."

julia> println("$x.")
1.

[StefanKarpinski]

This is a bug and it's specific to the name var. Making var"..." parse specially is having a lot more fallout than naively anticipated. cc @c42f

[KristofferC]

Fixed by #32948.

Let's not count multiple identical bug reports against a nice feature. :)

[matbesancon]

Ok my initial assumptions were extremely overfitted, thanks all

[StefanKarpinski]

Great. I'm glad that it's already fixed!