[Issue 20218] New: Checked format string takes infinite time for infinite ranges

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20218

          Issue ID: 20218
           Summary: Checked format string takes infinite time for infinite
                    ranges
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody at puremagic.com
          Reporter: acehreli at yahoo.com

dmd 2.088 does not stop compiling the following program seemingly because it is
expanding the infinite range at compile time:

import std.string;
import std.range;

void main() {
  format!"%s"(1.repeat);
}

1) SAME PROBLEM for writefln

2) SAME PROBLEM for element formatters %( and %):

  format!"%(%s%)"(1.repeat);

3) SIMILAR PROBLEM: Apparently, it can take "close to infinite time" if the
range is large. The following line either does not finish compilation or takes
a very long time (I did not wait):

  format!"%s"(1.repeat(1_000_000_000));

Ali

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