[SAY-5]

Summary

Fix assert.Equal reporting distinct atomic pointers to equal values as unequal.

Changes

• Compare values loaded from top-level pointers to the same instantiated sync/atomic.Pointer type, preserving nil and pointer-identity behavior.
• Keep ordinary and unsafe-pointer behavior unchanged; only the standard atomic Load method is invoked.
• Guard the implementation with go1.19 and provide an older-Go fallback without changing the Go 1.17 module requirement.
• Add regression, boundary, cycle, and concurrent-store tests. Generic tests use a go1.21 build tag to retain compatibility with the module's older language version.

The original 14-case regression fails only the reported atomic case before the fix and passes afterward. The full module race suite, go vet ./..., generation, and formatting pass on Go 1.26.2/macOS arm64. The same 14-case external consumer passes with the actual Go 1.19.13 compiler/runtime and default vet/linking. The broader Go-version matrix was not run locally and remains for CI.

Motivation

Equal documents equality of referenced values. Two *atomic.Pointer[int] values holding distinct pointers to equal integers currently fail that comparison. This implements the atomic-pointer behavior requested in #1403 while retaining the maintainer's restriction against dereferencing unsafe.Pointer.

Example usage

one, anotherOne := 1, 1
var left, right atomic.Pointer[int]
left.Store(&one)
right.Store(&anotherOne)
assert.Equal(t, &left, &right)

Related issues

Fixes #1403.

OpenAI Codex assisted with the implementation and tests; a separate Codex agent reviewed the patch and verification evidence.