https://issues.dlang.org/show_bug.cgi?id=13566
Issue ID: 13566
Summary: std.algorithm.cmp treats string length as element
Product: D
Version: D2
Hardware: x86_64
OS: Linux
Status: NEW
Severity: major
Priority: P1
Component: DMD
Assignee: [email protected]
Reporter: [email protected]
The following code cannot be compiled on a 64-bit environment:
import std.algorithm;
bool myPred(dchar a, dchar b)
{
return false;
}
void main()
{
cmp!myPred("", "");
}
phobos/std/algorithm.d(7314): Error: myPred (dchar a, dchar b) is not callable
using argument types (ulong, ulong)
phobos/std/algorithm.d(7314): Error: myPred (dchar a, dchar b) is not callable
using argument types (ulong, ulong)
deneme.d(179975): Error: template instance std.algorithm.cmp!(myPred, string,
string) error instantiating
A quick investigation reveals that one of the overloads of threeWay() inside
std.algorithm.cmp takes two size_t parameters that are supposed to be string
lengths. Unfortunately, threeWay() then tries to pass those lengths to the
predicate:
// For speed only
static int threeWay(size_t a, size_t b)
{
static if (size_t.sizeof == int.sizeof && isLessThan)
return a - b;
else
return binaryFun!pred(b, a) ? 1 : binaryFun!pred(a, b) ? -1 : 0; //
<-- HERE
}
I've also noticed that unittests of cmp() don't consider special predicates at
all. ;)
Ali
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