Delete the "del" flag

[mhauru]

InitContext made it redundant.

Could now change the whole flags structure to not be a dict, but might not be worth it if we could just switch over to VarNamedVector.

[github-actions]

Benchmark Report for Commit 1de7fed

Computer Information

Julia Version 1.11.7
Commit f2b3dbda30a (2025-09-08 12:10 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 4 × AMD EPYC 7763 64-Core Processor
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, znver3)
Threads: 1 default, 0 interactive, 1 GC (on 4 virtual cores)

Benchmark Results

┌───────────────────────┬───────┬─────────────┬───────────────────┬────────┬────────────────┬─────────────────┐
│                 Model │   Dim │  AD Backend │           VarInfo │ Linked │ t(eval)/t(ref) │ t(grad)/t(eval) │
├───────────────────────┼───────┼─────────────┼───────────────────┼────────┼────────────────┼─────────────────┤
│ Simple assume observe │     1 │ forwarddiff │             typed │  false │            9.1 │             1.5 │
│           Smorgasbord │   201 │ forwarddiff │             typed │  false │          659.3 │            42.2 │
│           Smorgasbord │   201 │ forwarddiff │ simple_namedtuple │   true │          424.0 │            53.1 │
│           Smorgasbord │   201 │ forwarddiff │           untyped │   true │         1185.6 │            28.6 │
│           Smorgasbord │   201 │ forwarddiff │       simple_dict │   true │         6983.2 │            26.2 │
│           Smorgasbord │   201 │ reversediff │             typed │   true │         1035.5 │            40.4 │
│           Smorgasbord │   201 │    mooncake │             typed │   true │         1021.4 │             4.7 │
│    Loop univariate 1k │  1000 │    mooncake │             typed │   true │         5757.3 │             4.3 │
│       Multivariate 1k │  1000 │    mooncake │             typed │   true │          974.4 │             9.6 │
│   Loop univariate 10k │ 10000 │    mooncake │             typed │   true │        63833.6 │             3.9 │
│      Multivariate 10k │ 10000 │    mooncake │             typed │   true │         8390.3 │            10.7 │
│               Dynamic │    10 │    mooncake │             typed │   true │          137.2 │            11.1 │
│              Submodel │     1 │    mooncake │             typed │   true │           12.4 │             5.1 │
│                   LDA │    12 │ reversediff │             typed │   true │         1031.8 │             2.0 │
└───────────────────────┴───────┴─────────────┴───────────────────┴────────┴────────────────┴─────────────────┘

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 6 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (breaking@7311465). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
src/varinfo.jl	42.85%	4 Missing ⚠️
src/threadsafe.jl	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             breaking    #1058   +/-   ##
===========================================
  Coverage            ?   82.39%           
===========================================
  Files               ?       41           
  Lines               ?     3799           
  Branches            ?        0           
===========================================
  Hits                ?     3130           
  Misses              ?      669           
  Partials            ?        0           

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[penelopeysm]

LGTM, though could you add a changelog entry? Feel free to merge afterwards.

[github-actions]

DynamicPPL.jl documentation for PR #1058 is available at:
https://TuringLang.github.io/DynamicPPL.jl/previews/PR1058/