[TT-Train] Fix GCC build: qualify self-referential using declarations (#37922)

[epam-iaroslav-voitovych]

Ticket

Fixes #37922

Problem description

5 tt-train device operation headers use self-referential using type alias declarations:

using operation_attributes_t = operation_attributes_t;  // unqualified — self-referential

This violates C++ [basic.scope.class]/2: the member name on the left shadows the namespace-scope type on the right, making the declaration self-referential. GCC (all versions) correctly rejects this with -fpermissive; Clang is lenient and accepts it.

8 other device operations in the same codebase already use the correct fully-qualified pattern.

What's changed

Added full namespace qualification to the using declarations in the 5 affected files, matching the pattern already used by rmsnorm_fw, rmsnorm_bw, softmax, silu_bw, cross_entropy_fw, cross_entropy_bw, sdpa_fw, and profiler_no_op.

Before (broken with GCC)

namespace ttml::metal::ops::layernorm_fw::device {
struct LayerNormForwardDeviceOperation {
    using operation_attributes_t = operation_attributes_t;
};
}

After (works with both GCC and Clang)

namespace ttml::metal::ops::layernorm_fw::device {
struct LayerNormForwardDeviceOperation {
    using operation_attributes_t = ttml::metal::ops::layernorm_fw::device::operation_attributes_t;
};
}

Files changed (5 files, 20 lines)

• tt-train/sources/ttml/metal/ops/layernorm_fw/device/layernorm_fw_device_operation.hpp
• tt-train/sources/ttml/metal/ops/layernorm_bw/device/layernorm_bw_device_operation.hpp
• tt-train/sources/ttml/metal/ops/swiglu_fw/device/swiglu_fw_device_operation.hpp
• tt-train/sources/ttml/metal/optimizers/adamw/device/adamw_device_operation.hpp
• tt-train/sources/ttml/metal/optimizers/sgd_fused/device/sgd_fused_device_operation.hpp

Verification

Container build with --tt-train-compiler gcc-12 merging this fix + PR #37166 (compiler selection) on top of main — verifies tt-train compiles successfully with GCC 12.

Checklist

• 
• 
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• New/Existing tests provide coverage for changes

Model tests

If your changes cover model-related code, you should run tests corresponding to affected models and platforms (Single card, T3K, Galaxy). "Choose your pipeline" workflows facilitate running multiple kinds of tests in a single run. Each offers models-mandatory and models-extended presets.
The former includes a minimal set of tests, to be run always. The latter extends that with additional ones - use your best judgement in deciding which is the most appropriate for your PR.

• 

  • models-mandatory preset (runs: Device perf regressions and Frequent model and ttnn tests)
  • models-extended preset (runs: the mandatory tests, plus Demo and Model perf tests)
  • other selection - specify runs

• 

  • models-mandatory preset (runs: Unit tests)
  • models-extended preset (runs: the mandatory tests, plus Demo and Model perf tests)
  • other selection - specify runs

• 

  • models-mandatory preset (runs: Quick tests)
  • models-extended preset (runs: the mandatory tests, plus Demo and Model perf tests)
  • other selection - specify runs

[epam-iaroslav-voitovych]

Container verification

Verified in Docker container builds using parameterized build scripts that merge branches on top of main and optionally override the tt-train compiler:

#	Test	Compiler	Branches merged	Result
1	gcc-12 override	gcc-12	This PR + PR #37166 (compiler selection)	PASSED
2	Default (no override)	clang-20 (inherited from CMakeCache.txt)	This PR + PR #37166	PASSED

Build 1 confirms GCC 12 now compiles tt-train successfully with the qualified using declarations.
Build 2 confirms no regression on the default Clang path.

Build commands used:

# Build 1: gcc-12 override
./build_tt_docker.sh --branch main \
  --merge-branch ivoitovych/issue-36993-fix-gcc-constexpr-lambda \
  --merge-branch ivoitovych/tt-metal:ivoitovych/issue-37922-fix-gcc-self-referential-using \
  --tt-train-compiler gcc-12

# Build 2: default compiler (clang-20 inherited from tt-metal CMakeCache.txt)
./build_tt_docker.sh --branch main \
  --merge-branch ivoitovych/issue-36993-fix-gcc-constexpr-lambda \
  --merge-branch ivoitovych/tt-metal:ivoitovych/issue-37922-fix-gcc-self-referential-using