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Use moved core.lifetime.forward for std.functional.forward #6847

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Merged
merged 1 commit into from
Feb 3, 2019
Merged

Use moved core.lifetime.forward for std.functional.forward #6847

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113 changes: 2 additions & 111 deletions std/functional.d
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Original file line number Diff line number Diff line change
Expand Up @@ -1613,28 +1613,8 @@ Returns:
*/
template forward(args...)
{
static if (args.length)
{
import std.algorithm.mutation : move;

alias arg = args[0];
// by ref || lazy || const/immutable
static if (__traits(isRef, arg) ||
__traits(isOut, arg) ||
__traits(isLazy, arg) ||
!is(typeof(move(arg))))
alias fwd = arg;
// (r)value
else
@property auto fwd(){ return move(arg); }

static if (args.length == 1)
alias forward = fwd;
else
alias forward = AliasSeq!(fwd, forward!(args[1..$]));
}
else
alias forward = AliasSeq!();
import core.lifetime : fun = forward;
alias forward = fun!args;
}

///
Expand Down Expand Up @@ -1678,49 +1658,6 @@ template forward(args...)
assert(s == "HelloHello");
}

@safe unittest
{
auto foo(TL...)(auto ref TL args)
{
string result = "";
foreach (i, _; args)
{
//pragma(msg, "[",i,"] ", __traits(isRef, args[i]) ? "L" : "R");
result ~= __traits(isRef, args[i]) ? "L" : "R";
}
return result;
}

string bar(TL...)(auto ref TL args)
{
return foo(forward!args);
}
string baz(TL...)(auto ref TL args)
{
int x;
return foo(forward!args[3], forward!args[2], 1, forward!args[1], forward!args[0], x);
}

struct S {}
S makeS(){ return S(); }
int n;
string s;
assert(bar(S(), makeS(), n, s) == "RRLL");
assert(baz(S(), makeS(), n, s) == "LLRRRL");
}

@safe unittest
{
ref int foo(return ref int a) { return a; }
ref int bar(Args)(auto ref Args args)
{
return foo(forward!args);
}
static assert(!__traits(compiles, { auto x1 = bar(3); })); // case of NG
int value = 3;
auto x2 = bar(value); // case of OK
}

///
@safe unittest
{
Expand Down Expand Up @@ -1787,49 +1724,3 @@ template forward(args...)
// const rvalue, copy
assert(z4.x_.i == 1);
}

// lazy -> lazy
@safe unittest
{
int foo1(lazy int i) { return i; }
int foo2(A)(auto ref A i) { return foo1(forward!i); }
int foo3(lazy int i) { return foo2(i); }

int numCalls = 0;
assert(foo3({ ++numCalls; return 42; }()) == 42);
assert(numCalls == 1);
}

// lazy -> non-lazy
@safe unittest
{
int foo1(int a, int b) { return a + b; }
int foo2(A...)(auto ref A args) { return foo1(forward!args); }
int foo3(int a, lazy int b) { return foo2(a, b); }

int numCalls;
assert(foo3(11, { ++numCalls; return 31; }()) == 42);
assert(numCalls == 1);
}

// non-lazy -> lazy
@safe unittest
{
int foo1(int a, lazy int b) { return a + b; }
int foo2(A...)(auto ref A args) { return foo1(forward!args); }
int foo3(int a, int b) { return foo2(a, b); }

assert(foo3(11, 31) == 42);
}

// out
@safe unittest
{
void foo1(int a, out int b) { b = a; }
void foo2(A...)(auto ref A args) { foo1(forward!args); }
void foo3(int a, out int b) { foo2(a, b); }

int b;
foo3(42, b);
assert(b == 42);
}