runtime: reflect Value.Seq/Seq2

[visualfc]

• runtime: support reflect.Value.Seq/Seq2
• ssa/abi: fix structure name public if it is a closure
• _demo/go: add text/template demo

[gemini-code-assist]

Summary of Changes

Hello @visualfc, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces new Seq and Seq2 methods to the reflect.Value type, providing a standardized way to obtain single-value and key-value iterators, respectively, for a wide range of Go types. These additions leverage the iter package to integrate Go's iteration proposals with the reflection system, allowing for dynamic traversal of data structures. The changes are part of an ongoing effort, with a known ABI type error still requiring resolution.

Highlights

• New Iteration Methods: Introduced Seq() and Seq2() methods to reflect.Value, enabling reflection-based iteration over various Go data structures using the new iter package.
• Supported Types for Iteration: The Seq() method supports iteration over numeric types, pointers to arrays, arrays, slices, strings (indices), maps (keys), channels (received values), and specific function signatures. The Seq2() method supports iteration over pointers to arrays (index, element), arrays, slices (index, element), strings (index, rune), maps (key, value), and specific function signatures.
• New Internal Package: A new file iter.go has been added to the internal runtime/internal/lib/reflect package, containing the implementation for these new reflection iteration capabilities.
• Work In Progress: This pull request is marked as a Work In Progress ([WIP]) and has a known 'abi type error' that needs to be addressed.

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[gemini-code-assist]

Code Review

This pull request introduces Value.Seq and Value.Seq2 to support ranging over reflect.Values. The implementation covers various kinds like integers, arrays, slices, strings, maps, channels, and functions. I've found a critical bug in the handling of pointers to arrays in both Seq and Seq2 that would cause a panic on subsequent uses of an iterator. I've suggested a refactoring that fixes this bug and also reduces code duplication. Additionally, I've pointed out an unclear comment that could be improved for better maintainability.

[xgopilot]

Code Review Summary

Solid implementation of Go 1.23 iterator support for reflect.Value. The code structure is clean and follows reflect package patterns well.

Critical Issues:

• Nil pointer checks missing (lines 73, 137) - could cause panics
• Resource exhaustion risk with large integers - no iteration limits
• Documentation doesn't specify what's yielded per type (indices vs elements)

Other Notable:

• Inconsistent Kind() vs kind() usage (line 135)
• Heavy allocation overhead in loops (ValueOf per iteration)

Overall well-written, but security and documentation gaps need attention before merge.

[codecov]

Codecov Report

❌ Patch coverage is 10.00000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.54%. Comparing base (7135b63) to head (f911fa5).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
ssa/abi/abi.go	0.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1442      +/-   ##
==========================================
- Coverage   90.65%   90.54%   -0.12%     
==========================================
  Files          43       43              
  Lines       11419    11423       +4     
==========================================
- Hits        10352    10343       -9     
- Misses        904      917      +13     
  Partials      163      163              

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