fix generic local runtime type names

[cpunion]

Summary

• Fix reflected runtime names for nested generic local types by formatting type arguments with reflect-style package paths (command-line-arguments becomes main).
• Stop adding the local ordinal suffix to the primary instantiated local generic type name while preserving suffixes for local types used as type arguments.
• Add stable test/go coverage for package and command-line main cases, and remove the now-fixed typeparam/nested.go GOROOT xfails.

GOROOT CI

Full GOROOT CI is disabled for normal PRs (workflow_dispatch only) and is too slow for routine validation. This PR adds test/go coverage so the regression remains covered when GOROOT CI is not running.

A manual GOROOT workflow was dispatched on an upstream branch with the same head SHA because GitHub rejected dispatching refs/pull/1879/head directly: https://github.com/xgo-dev/llgo/actions/runs/26263992315

Targeted GOROOT commands run locally with $(go env GOROOT) = /opt/homebrew/Cellar/go@1.24/1.24.11/libexec:

go test ./test/goroot -run TestGoRoot -count=1 -timeout=10m -args -goroot "$(go env GOROOT)" -dirs typeparam -case '^typeparam/nested\.go$' -xfail /tmp/llgo-no-xfail.yaml -directive-mode legacy

go test ./test/goroot -run TestGoRoot -count=1 -timeout=10m -args -goroot "$(go env GOROOT)" -dirs typeparam -case '^typeparam/nested\.go$' -directive-mode legacy

Tests

go test ./test/go -run 'TestGeneric(LocalRuntimeTypesIncludeOuterArgs|NestedLocalRuntimeTypeNames)' -count=1
go run ./cmd/llgo test -run 'TestGeneric(LocalRuntimeTypesIncludeOuterArgs|NestedLocalRuntimeTypeNames)' ./test/go
go test ./cl -run 'TestGenericLocalTypePatch|TestGenericLocalTypePatchHelperBranches' -count=1
go test ./ssa/abi -count=1
go test ./test/goroot -run TestGoRoot -count=1 -timeout=10m -args -goroot "$(go env GOROOT)" -dirs typeparam -case '^typeparam/nested\.go$' -xfail /tmp/llgo-no-xfail.yaml -directive-mode legacy
go test ./test/goroot -run TestGoRoot -count=1 -timeout=10m -args -goroot "$(go env GOROOT)" -dirs typeparam -case '^typeparam/nested\.go$' -directive-mode legacy
go test ./cl -count=1

[cpunion]

CI update: branch codex/goroot-typeparam-coverage is present in xgo-dev/llgo; dispatched another manual GOROOT workflow for this head SHA. Run: https://github.com/xgo-dev/llgo/actions/runs/26264734516. Existing earlier run: https://github.com/xgo-dev/llgo/actions/runs/26263992315

[cpunion]

Correction: per branch policy, the temporary xgo-dev/llgo:codex/goroot-typeparam-coverage ref used for manual workflow dispatch has been deleted. The PR head remains cpunion/llgo:codex/goroot-typeparam-coverage. Normal PR CI remains attached to this draft PR; manual GOROOT workflow_dispatch cannot be run without an upstream ref.

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[cpunion]

CI follow-up for #1879:

• Investigated the two failing jobs. Both failures happened before the branch-specific tests ran:
  • test (macos-latest, 19, 1.24.2, 3) failed while downloading Go: curl: (6) Could not resolve host: go.dev.
  • llgo (ubuntu-latest, 19, 1.24.2) failed while pip was downloading the torch wheel from files.pythonhosted.org: read timeout.
• No code/test change was needed for these failures; branch head remains 861710e41945854130dfc4b11dbcf14d971684bc.
• Local validation passed:
  • go test ./cl -run 'TestGenericLocalTypePatch|TestFuncName'
  • go test ./test/go -run 'TestGeneric(LocalRuntimeTypesIncludeOuterArgs|NestedLocalRuntimeTypeNames|NestedLocalRuntimeTypeNamesForCommandLineMain)'
• Reran the failed CI jobs:
  • llgo (ubuntu-latest, 19, 1.24.2) rerun passed: https://github.com/xgo-dev/llgo/actions/runs/26263988346/job/77405365432
  • test (macos-latest, 19, 1.24.2, 3) rerun is still queued with no runner assigned yet: https://github.com/xgo-dev/llgo/actions/runs/26263956054/job/77405342396

PR remains draft and CI is enabled.

[cpunion]

Typeparam follow-up update at 8bd8bfe.

What changed:

• Clarified the remaining typeparam goroot xfail reasons in test/goroot/xfail.yaml.
• No compiler/runtime code change in this follow-up because the remaining failures reproduced as non-typeparam roots.

Case classification:

• Covered by the existing PR fix: typeparam/nested.go passes locally with xfail disabled on Go 1.24.11 and Go 1.25.7.
• Left xfailed, not mixed into this PR: typeparam/chans.go and typeparam/orderedmap.go reproduce as a non-generic select/unbuffered-channel issue.
• Left xfailed, not mixed into this PR: typeparam/issue51521.go and typeparam/mdempsky/16.go reproduce as a non-generic nil-deref panic value not implementing error/runtime.Error.
• Left xfailed, not mixed into this PR: typeparam/mdempsky/15.go reproduces as //go:nointerface methods still satisfying interfaces, including a non-generic reduced case.
• Left xfailed, not mixed into this PR: typeparam/typeswitch5.go has the expected type-switch behavior, but differs only in println float exponent formatting (+9.000000e+00 vs +9.000000e+000).

Validation run locally:

• go test ./test/goroot -run 'Test.*XFail|Test.*Runner|TestGoRootRunCases' -count=1
• go test ./test/go -count=1
• go test ./cl -run 'TestGenericLocalTypePatchHelpers|TestGenericLocalTypePatchHelperBranches|TestFuncName_NestedClosureInMethodIncludesRecv|TestFuncName_TopLevelAndPlainClosureNoRecv|TestFuncName_ThunkAndBoundStillCarryRecv' -count=1
• go test ./ssa ./ssa/abi -run 'TestHasTypeParam|TestTypeName_DetachedLocalScopeUsesPosition|TestTypeName_GenericLocal|TestTypeName_Local|TestTypeName' -count=1
• Go 1.24.11 goroot sanity with default xfail for top-level listed typeparam cases: pass
• Go 1.24.11 goroot sanity with default xfail for typeparam/mdempsky/{15,16}.go in runlike mode: pass
• Go 1.25.7 goroot sanity with default xfail for top-level listed typeparam cases: pass
• Go 1.25.7 goroot sanity with default xfail for typeparam/mdempsky/{15,16}.go in runlike mode: pass

PR remains draft and CI is enabled/running.