Bug 18285 – std.algorithm.comparison.cmp for strings with custom predicate compares lengths wrong

Discussion: https://github.com/dlang/phobos/pull/6056#pullrequestreview-90703862 Sample code demonstrating bug: https://run.dlang.io/is/RJnPBw ``` void main() { import std.algorithm.comparison : cmp; // Note that "a > b" is the reverse of the normal. static assert(cmp!"a > b"("1", "2") > 0); // Following fails because cmp is using the predicate "a > b" // to compare the lengths of the ranges. static assert(cmp!"a > b"("abc", "abcd") < 0, `Should be negative because "abc" is a prefix of "abcd"!`); } ```

Fixed https://github.com/dlang/phobos/pull/6056 https://github.com/dlang/phobos/commit/7f59e5ad526ee4bf856e8235e3042bb5cd442ad4