Fix export= class visibility alongside top-level export type

[Wesley Wigham (weswigham)]

By doing some recursive alias resolution comparison, to handle our now non-terminal aliases.

Fixes #64249

I don't think this is actually a regression, since the declaration file in question was actually an error prior to TS7 and it was just being suppressed by skipLibCheck so it sorta-kinda worked. But! It's supported first-class now (export= merging with top level export type, anyway), so it does actually need fixing.

[Copilot]

Copilot review overview

🟡 Changes recommended

The implementation unwraps only one additional merged alias, leaving longer valid alias chains inaccessible.

Review effort: Balanced
Findings: 1

Open (1)

• Resolve multi-layer merged alias chains · New

What changed in this PR

This PR updates symbol accessibility to support export = classes merged with top-level type exports, addressing TS4094.

Changes:

• Resolves an additional alias during accessibility checks.
• Adds declaration-emit regression tests across three module modes.
• Updates affected symbol and type baselines.

File	Description
tsc/​internal/​checker/​symbolaccessibility.go	Extends alias comparison.
tsc/​testdata/​tests/​cases/​compiler/​declarationEmitDefaultImportPrivateClass.ts	Tests default-import visibility.
tsc/​testdata/​tests/​cases/​compiler/​declarationEmitExportAssignmentWithTypeExports.ts	Tests export-assignment import forms.
tsc/​testdata/​tests/​cases/​compiler/​declarationEmitMergedExportAlias.ts	Tests merged re-export aliases.
tsc/​testdata/​baselines/​reference/​compiler/​cjsExportGenericTypes.types	Updates inferred alias names.
tsc/​testdata/​baselines/​reference/​compiler/​exportAssignmentMerging2.symbols	Updates symbol names.
tsc/​testdata/​baselines/​reference/​compiler/​exportAssignmentMerging2.types	Updates type names.
tsc/​testdata/​baselines/​reference/​compiler/​exportAssignmentMerging3.symbols	Updates symbol names.
tsc/​testdata/​baselines/​reference/​compiler/​exportAssignmentMerging3.types	Updates type names.
tsc/​testdata/​baselines/​reference/​compiler/​noCrashOnImportShadowing.types	Updates inferred aliases.
tsc/​testdata/​baselines/​reference/​conformance/​exportTypeMergedWithExportStarAsNamespace.symbols	Updates merged symbols.
tsc/​testdata/​baselines/​reference/​conformance/​exportTypeMergedWithExportStarAsNamespace.types	Updates merged types.
tsc/​testdata/​baselines/​reference/​conformance/​importElisionConstEnumMerge1.types	Updates enum alias types.
tsc/​testdata/​baselines/​reference/​conformance/​typeAndNamespaceExportMerge.symbols	Updates merged symbols.
tsc/​testdata/​baselines/​reference/​conformance/​typeAndNamespaceExportMerge.types	Updates merged types.
tsc/​testdata/​baselines/​reference/​compiler/​declarationEmitDefaultImportPrivateClass(module=commonjs).js	Adds CommonJS emit baseline.
…(module=commonjs).symbols	Adds CommonJS symbol baseline.
…(module=commonjs).types	Adds CommonJS type baseline.
…(module=nodenext).js	Adds NodeNext emit baseline.
…(module=nodenext).symbols	Adds NodeNext symbol baseline.
…(module=nodenext).types	Adds NodeNext type baseline.
…(module=preserve).js	Adds preserve emit baseline.
…(module=preserve).symbols	Adds preserve symbol baseline.
…(module=preserve).types	Adds preserve type baseline.
tsc/​testdata/​baselines/​reference/​compiler/​declarationEmitExportAssignmentWithTypeExports(module=commonjs).js	Adds CommonJS emit baseline.
…(module=commonjs).symbols	Adds CommonJS symbol baseline.
…(module=commonjs).types	Adds CommonJS type baseline.
…(module=nodenext).js	Adds NodeNext emit baseline.
…(module=nodenext).symbols	Adds NodeNext symbol baseline.
…(module=nodenext).types	Adds NodeNext type baseline.
…(module=preserve).js	Adds preserve emit baseline.
…(module=preserve).symbols	Adds preserve symbol baseline.
…(module=preserve).types	Adds preserve type baseline.
tsc/​testdata/​baselines/​reference/​compiler/​declarationEmitMergedExportAlias(module=commonjs).js	Adds CommonJS emit baseline.
…(module=commonjs).symbols	Adds CommonJS symbol baseline.
…(module=commonjs).types	Adds CommonJS type baseline.
…(module=nodenext).js	Adds NodeNext emit baseline.
…(module=nodenext).symbols	Adds NodeNext symbol baseline.
…(module=nodenext).types	Adds NodeNext type baseline.
…(module=preserve).js	Adds preserve emit baseline.
…(module=preserve).symbols	Adds preserve symbol baseline.
…(module=preserve).types	Adds preserve type baseline.

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[Jake Bailey (jakebailey)]

There's actually an AddIfPresent func for these that would work but it's equivalent enough