Fix bc_assign_slots corrupting OP_JMP offsets for standalone event calls#899
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IgorYbema merged 1 commit intoMay 30, 2026
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When a standalone call (e.g. dhw_start();) appears inside an if-block, the TSEMICOLON handler resets OP_CALL.a to 0. The segment detection in bc_assign_slots only sets `start` when it finds a node with a > 0, so with OP_CALL.a = 0 `start` stayed at 0. Loop1 then scanned from byte 0 through all preceding bytecode, corrupting OP_JMP jump offsets to -1 and breaking the if-branch entirely. Fix 1: initialise start = end after the skip-JMPs step so that when no positive-slot node is found the loops scan only the actual segment. Fix 2: add the same OP_CALL/a==0 continue to loop2 that loop1 already had, preventing loop2 from overwriting the no-return-value sentinel with a heap slot reference. Fixes heishamon#894 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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When a standalone call (e.g. dhw_start();) appears inside an if-block, the TSEMICOLON handler resets OP_CALL.a to 0. The segment detection in bc_assign_slots only sets
startwhen it finds a node with a > 0, so with OP_CALL.a = 0startstayed at 0. Loop1 then scanned from byte 0 through all preceding bytecode, corrupting OP_JMP jump offsets to -1 and breaking the if-branch entirely.Fix 1: initialise start = end after the skip-JMPs step so that when no positive-slot node is found the loops scan only the actual segment.
Fix 2: add the same OP_CALL/a==0 continue to loop2 that loop1 already had, preventing loop2 from overwriting the no-return-value sentinel with a heap slot reference.
Fixes #894