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digitalmars.D.learn - druntime 2.087 regression? (was: Old codebase stops compiling at

reply James Blachly <james.blachly gmail.com> writes:
TL;DR druntime regression? 
https://gist.github.com/jblachly/78c5762bbfea65b09e7a1417ad763019

---

Our team has an older codebase that compiled fine up until frontend 
version 2.087 (builds with 2.086.1).  Now, compiler (DMD2 and LDC2) 
complains about implicit conversion of shared(AA) to const(shared(AA)).

The codebase is private (could possibly make it public soon) but the 
error involves an AA inside a shared struct.

```
/home/james/dmd2.087/dmd2/linux/bin64/../../src/druntime/impor
/object.d(3453,36): 
Error: cannot implicitly convert expression aa of type 
shared(GSeqAllele[string]) to const(shared(GSeqAllele)[string])

source/polytyper/gseq.d(231,33): Error: template instance 
`object.values!(shared(GSeqAllele[string]), shared(GSeqAllele), string)` 
error instantiating

/home/james/dmd2.087/dmd2/linux/bin64/../../src/druntime/impor
/object.d(3402,36): 
Error: cannot implicitly convert expression aa of type 
shared(GSeqAllele[string]) to const(shared(GSeqAllele)[string])

source/polytyper/gseq.d(280,35): Error: template instance 
`object.keys!(shared(GSeqAllele[string]), shared(GSeqAllele), string)` 
error instantiating
```
(line breaks added for clarity)

The two triggering lines both iterate over a built-in AA

gseq.d:231:        foreach (a; this.alleles.values)
gseq.d:208:        foreach (key; this.alleles.keys)

Looking at the changelog for 2.087 ( 
https://dlang.org/changelog/2.087.0.html ) I do not see any obvious 
culprits. git blame suggests this is the responsible commit:

https://github.com/dlang/druntime/commit/af86e7db58f4b792e45bdc3ee43c17aadc9d54ab#diff-a68e58fcf0de5aa198fcaceafe4e8cf9L3430-R3454

 From this change, it looks like the runtime now cannot handle a shared 
AA -- is this right? A minimal reproducible example is here: 
https://gist.github.com/jblachly/78c5762bbfea65b09e7a1417ad763019

Thanks in advance for help
James

PS: Why is this commit ("object: Declare private struct AA and fix aaA 
function signatures ") not mentioned in the changelog?
Nov 17 2019
parent reply Steven Schveighoffer <schveiguy gmail.com> writes:
On 11/17/19 10:45 AM, James Blachly wrote:


 /home/james/dmd2.087/dmd2/linux/bin64/../../src/druntime/impor
/object.d(3453,36): 
 Error: cannot implicitly convert expression aa of type 
 shared(GSeqAllele[string]) to const(shared(GSeqAllele)[string])


There's a subtle removing of the shared from the entire AA. Is that on 
purpose?

i.e. I see shared(GSeqAllele[string]) in one, and 
shared(GSeqAllele)[string] in another.

-Steve
Nov 17 2019
parent reply James Blachly <james.blachly gmail.com> writes:
On 11/17/19 7:15 PM, Steven Schveighoffer wrote:

 On 11/17/19 10:45 AM, James Blachly wrote:
 

 /home/james/dmd2.087/dmd2/linux/bin64/../../src/druntime/impor
/object.d(3453,36): 
 Error: cannot implicitly convert expression aa of type 
 shared(GSeqAllele[string]) to const(shared(GSeqAllele)[string])


 
 There's a subtle removing of the shared from the entire AA. Is that on 
 purpose?
 
 i.e. I see shared(GSeqAllele[string]) in one, and 
 shared(GSeqAllele)[string] in another.
 
 -Steve


Steve:

Sorry for the delay in replying. That is the runtime removing the shared 
from the entire AA, not our code. I point out the change that induces 
this with a link to github.

Should I move this discussion to the main D group? My primary concerns are:

0. Ask if it is intended behavior that the runtime cannot handle a 
shared AA post 2.086.1?

1. Report this as bug

2. Ask why this commit ("object: Declare private struct AA and fix aaA 
function signatures ") not mentioned in the changelog for 2.087?

Thanks in advance
Dec 03 2019
parent Steven Schveighoffer <schveiguy gmail.com> writes:
On 12/3/19 12:15 PM, James Blachly wrote:

 On 11/17/19 7:15 PM, Steven Schveighoffer wrote:

 On 11/17/19 10:45 AM, James Blachly wrote:


 /home/james/dmd2.087/dmd2/linux/bin64/../../src/druntime/impor
/object.d(3453,36): 
 Error: cannot implicitly convert expression aa of type 
 shared(GSeqAllele[string]) to const(shared(GSeqAllele)[string])


 There's a subtle removing of the shared from the entire AA. Is that on 
 purpose?

 i.e. I see shared(GSeqAllele[string]) in one, and 
 shared(GSeqAllele)[string] in another.


 Steve:
 
 Sorry for the delay in replying. That is the runtime removing the shared 
 from the entire AA, not our code. I point out the change that induces 
 this with a link to github.


I admit, this was a drive-by analysis, and I didn't look at the code at 
all. Just the error.


 
 Should I move this discussion to the main D group? My primary concerns are:
 
 0. Ask if it is intended behavior that the runtime cannot handle a 
 shared AA post 2.086.1?
 
 1. Report this as bug
 
 2. Ask why this commit ("object: Declare private struct AA and fix aaA 
 function signatures ") not mentioned in the changelog for 2.087?


0. learn is fine. I'm never one to care about where someone posts.

1. Bugzilla is the correct place to report. Looks like you have a solid 
case and have done all the hard work. Should be fixable.

2. Not all commits are mentioned in the changelog. But if there is a 
change that breaks existing code, arguably it should be in there.

-Steve
Dec 03 2019