context pointer does not apply qualifiers properly

[dlangBugzillaToGithub]

Nicholas Wilson (@thewilsonator) reported this on 2019-06-14T08:05:25Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=19961

CC List

• Walter Bright (@WalterBright)

Description

void main()
{
    int i = 42;    
    // const should not be able to access mutable.
    int* p = &i;
    auto dg2 = delegate int() const { return *p; };
    assert(dg2() == i);
}

fails to error.

Also 

void main()
{
    int i = 42;    
    // shared cannot access mutable
    int* p = &i;
    auto dg2 = delegate int() shared { return *p; };
    assert(dg2() == i);
}

errors, the context should be captured as shared so that should be allowed. Issue 15306 declared this accepts invalid as shared aliasing but I believe that is incorrect. Shared doesn't offer any useful guaruntees on that front anyway.

[dlangBugzillaToGithub]

iamthewilsonator commented on 2019-06-14T08:09:45Z

Bleaugh. That should be 
auto dg2 = delegate int() const { return *p++; };

[dlangBugzillaToGithub]

iamthewilsonator commented on 2019-06-14T08:10:19Z

Bleaugh. That should be 
auto dg2 = delegate int() const { return *p++; };

[dlangBugzillaToGithub]

bugzilla (@WalterBright) commented on 2019-06-14T09:58:24Z

Partial fix: https://github.com/dlang/dmd/pull/10035

[dlangBugzillaToGithub]

iamthewilsonator commented on 2019-06-17T12:55:12Z

So the real issue is:

struct S
{
    int x;
    void foo() const
    {
        pragma(msg, typeof(x)); // const(int)
    }
}

void test()
{
    void nested() const
    {
        pragma(msg, typeof(x)); // int
    }
}