[ASDAlexander77]

Fixes the v0.0-pre-alpha85 release build, which failed on all four platforms (run 36038070141).

What broke

With --di, the .eh.copy.box.* copy thunk a class throw needs was built at the throw statement's location, and that location carries the statement's debug scope. When the throw is inside a braced block, the scope is a lexical block of the enclosing function. The thunk then got a subprogram of its own while its instructions still pointed into the other function, and LLVM rejected the module:

!dbg attachment points at wrong subprogram for function
!5857 = distinct !DISubprogram(name: ".eh.copy.box.PEAVError@@", ...)
tslang: error: Failed to emit LLVM IR

DefaultLib's debug build (--di, no --opt) throws RangeError inside blocks (fetch, Array.with), so it stopped emitting:

• Windows: LNK1181: cannot open input file '.\lib\debug\gc\lib.obj'
• Linux: cannot find -lTypeScriptDefaultLibCore, then debug/compile 0/155

Every release variant passed. PR CI is Release-only, and although the suite runs with --di, none of its throws sat in a braced block, so nothing caught this before the tag. When the throw is not in a block, the thunk silently took the enclosing function's subprogram. That was wrong too, but the verifier accepted it.

Fix

mlirGenCatchCopyThunk now does what a function declaration does (MLIRGenFunctions.cpp): it opens a debug scope, creates a subprogram for the thunk, and locates the body under it using the statement's plain location.

Tests

• New 00throw_in_block_debug_info.ts (compile + jit; the runner already passes --di --opt_level=0). It fails on main with the exact CI error and passes with the fix.
• Windows release suite: 2884/2884.
• DefaultLib built locally with this compiler: debug/gc build succeeds. Tests: release/compile 155/155, release/jit 155/155, debug/compile 155/155, debug/jit 155/155.

Not in this PR

Compiling a file that throws with --di --opt still fails, with a different error ("inlinable function call in a function with a DISubprogram location must have a debug location"). This existed before this change and doesn't affect the release, since the debug default lib is built without --opt.

After merge, the release needs a new tag: v0.0-pre-alpha85 points at 5671e4c4 and no release object was created from it.

🤖 Generated with Claude Code