Fix cross-module diamond-extends interface silently corrupting data - #268
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interface Combined extends Left, Right (2+ extends targets) had two bugs: mlirGen(InterfaceDeclaration) re-running for an already-declared interface duplicated its extends list unboundedly (every other member-add is idempotent, this push_back wasn't), and the per-object vtable patch loop used a method's standalone virtualIndex instead of its offset within the combined vtable, mis-patching every method from the second extends target onward. Adds cross-module regression coverage for diamond extends (isolated) and multilevel+diamond together, extending the same-module coverage from #267 across the module boundary. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This was referenced Jul 20, 2026
ASDAlexander77
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Adds a cross-module test pair for `interface Combined extends A, B, C` to stress the vtable-offset accumulation and extends-dedup guard from PR #268 (which only had 2-target diamond coverage) at N=3. Verified via live debug trace that the fix generalizes correctly; full extends-interface test family (12 tests) passes. Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
ASDAlexander77
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Jul 20, 2026
Adds a cross-module test pair for `interface Combined extends A, B, C` to stress the vtable-offset accumulation and extends-dedup guard from PR #268 (which only had 2-target diamond coverage) at N=3. Verified via live debug trace that the fix generalizes correctly; full extends-interface test family (12 tests) passes. Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
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Summary
interface Combined extends Left, Right(2+ extends targets, i.e. diamond) silently corrupted data cross-module, from two independent bugs:mlirGen(InterfaceDeclaration)can re-run for an already-declared interface; the heritage-clause loop unconditionally appended toextendson every run instead of guarding like every other member-add (getFieldIndex/getMethodIndexchecks), so the combined vtable's slot count multiplied without bound.virtualIndexinstead of its offset within the combined vtable, so every method from the second (or later)extendstarget got patched into the wrong slot.Test plan
export/import_object_literal_structural_typed_extends_interface_diamond.ts) and combined multilevel+diamond (export/import_object_literal_structural_typed_extends_interface_multilevel.ts), both compile+JIT variants, registered intest/tester/CMakeLists.txt.--emit=mlirdump before/after each fix (vtable slot count and patched slot indices).Co-Authored-By: Claude Sonnet 5 noreply@anthropic.com