[Issue 17764] New: [scope][DIP1000] Escape checker defeated by composition transformations
via Digitalmars-d-bugs
digitalmars-d-bugs at puremagic.com
Sat Aug 19 14:51:08 PDT 2017
https://issues.dlang.org/show_bug.cgi?id=17764
Issue ID: 17764
Summary: [scope][DIP1000] Escape checker defeated by
composition transformations
Product: D
Version: D2
Hardware: All
OS: All
Status: NEW
Severity: major
Priority: P1
Component: dmd
Assignee: nobody at puremagic.com
Reporter: petar.p.kirov at gmail.com
At first I was about to name this issue "The compiler treats 'scope ref T' and
'scope ref T[1]' differently" (see `use0x3()` and `use0x4()`), but then I
decided to dig a little more, so here's what I've found so far:
$ cat > scope_bug.d << DBUG
@safe:
struct Context0x0 { char[] str; }
struct Parent0x1 { Context0x0 c; }
struct Parent0x2 { Context0x0[1] csa; }
struct Parent0x3 { Context0x0[] csl; }
struct Parent0x4 { Context0x0* cp; }
struct Parent0x5 { Parent0x1 p1; }
struct Parent0x6 { Parent0x5 p5; }
struct Parent0x7 { Parent0x6 p6; }
struct Parent0x8 { Parent0x2[1]* p2; }
struct Parent0x9 { Parent0x8[1] p8; }
struct Parent0xA { Parent0x9[1] p9; }
struct Parent0xB { Parent0x4* p4; }
struct Parent0xC { Parent0xB* pb; }
struct Parent0xD { Parent0xC* pc; }
void main()
{
char[16] buf;
use0x0(buf);
char[] charSlice = buf;
use0x1(charSlice);
// use0x2(&charSlice); // NG - rejects valid
Context0x0[1] c = Context0x0(charSlice);
use0x3(c[0]);
use0x4(c);
use0x5(c);
auto p1 = Parent0x1(c[0]);
use0x6(p1);
auto p2 = Parent0x2(c);
use0x7(p2);
Context0x0[] contextSlice = c[];
auto p3 = Parent0x3(contextSlice);
use0x8(p3);
auto p4 = Parent0x4(&c[0]);
use0x9(p4);
auto p5 = Parent0x7(Parent0x6(Parent0x5(p1)));
use0xA(p5);
Parent0x2[1] p2sa = Parent0x2(c);
Parent0xA p6 = Parent0xA(Parent0x9(Parent0x8(&p2sa)));
use0xB(p6);
// auto pbAttemp1 = Parent0xB(&p4); // NG - rejects valid
Parent0x4[1] p4WorkAround = Parent0x4(&c[0]);
Parent0xB[1] pb = Parent0xB(&p4WorkAround[0]);
Parent0xC[1] pc = Parent0xC(&pb[0]);
Parent0xD[1] pd = Parent0xD(&pc[0]);
use0xC(pd[0]);
}
char[] global;
void use0x0(scope char[] arr)
{
// global = arr; // OK - this does not compile
}
void use0x1(scope ref char[] arr)
{
// global = arr; // OK - this does not compile
}
void use0x2(scope char[]* arr)
{
global = *arr; // NG - accepts invalid
}
void use0x3(scope ref Context0x0 c)
{
// global = c.str; // OK - this does not compile
}
void use0x4(scope ref Context0x0[1] c)
{
global = c[0].str; // NG - accepts invalid
}
void use0x5(scope Context0x0[] c)
{
global = c[0].str; // NG - accepts invalid
}
void use0x6(scope ref Parent0x1 p)
{
// global = p.c.str; // OK - this does not compile
}
void use0x7(scope ref Parent0x2 p)
{
global = p.csa[0].str; // NG - accepts invalid
}
void use0x8(scope ref Parent0x3 p)
{
global = p.csl[0].str; // NG - accepts invalid
}
void use0x9(scope ref Parent0x4 p)
{
global = p.cp.str; // NG - accepts invalid
}
void use0xA(scope ref Parent0x7 p)
{
// global = p.p6.p5.p1.c.str; // OK - this does not compile
}
void use0xB(scope ref Parent0xA p)
{
global = (*p.p9[0].p8[0].p2)[0].csa[0].str; // NG - accepts invalid
}
void use0xC(scope ref Parent0xD p)
{
global = p.pc.pb.p4.cp.str; // NG - accepts invalid
}
DBUG
$ dmd -dip1000 scope_bug.d
scope_bug.d(11): Error: cannot take address of scope local c in @safe function
main
$ dmd --version
DMD64 D Compiler v2.076.0-b1-master-32bb4ed
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