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2022-09-11 r/4801 refactor(tvix/eval): capture entire with_stack in upvaluesVincent Ambo5-149/+123
This completely rewrites the handling of "dynamic upvalues" to, instead of resolving them at thunk/closure instantiation time (which forces some values too early), capture the entire with stack of parent contexts if it exists. There are a couple of things in here that could be written more efficiently, but I'm first working through this to get to a bug related to with + recursion and the code complexity of some of the optimisations is distracting. Change-Id: Ia538e06c9146e3bf8decb9adf02dd726d2c651cf Reviewed-on: https://cl.tvl.fyi/c/depot/+/6486 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4800 refactor(tvix/eval): introduce Upvalues struct in closures & thunksVincent Ambo4-30/+65
This struct will be responsible for tracking upvalues (and is a convenient place to introduce optimisations for reducing value clones) instead of a plain value vector. The main motivation for this is that the upvalues will have to capture the `with`-stack fully and I want to avoid duplicating the logic for this between the two capturing types. Change-Id: I6654f8739fc2e04ca046e6667d4a015f51724e99 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6485 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4799 fix(tvix/eval): use correct lambda address in observerVincent Ambo1-1/+1
Instead of the reference to the Rc, print the address of the Rc itself. Change-Id: I4560598924db7d2864d5c4ae9af847aee2ea7eff Reviewed-on: https://cl.tvl.fyi/c/depot/+/6471 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4798 fix(tvix/eval): correctly account for slots during list constructionVincent Ambo3-1/+32
Similarly to attribute sets, list elements can be arbitrary expressions and their (temporary) stack slots during construction must be accounted for by the compiler. Change-Id: I3b6f7927860627fd867c64d0cab9104fd636d4f5 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6470 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4797 refactor(tvix/eval): cut down one iteration over locals arrayVincent Ambo1-1/+2
Caught by sterni in cl/6339 Change-Id: I2f2cd746114f14854cf599a7223a42a3e8ebe4fc Reviewed-on: https://cl.tvl.fyi/c/depot/+/6469 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4796 fix(tvix/eval): account for attrset temporaries during constructionVincent Ambo5-2/+68
The temporaries left on the stack as operands to `OpAttrs` must be accounted for in the locals array in order for operations within them to receive correct slots. Some test cases that were previously broken have been added. Change-Id: Ib52b629bbdf7931f63fd45a45af1073022da923c Reviewed-on: https://cl.tvl.fyi/c/depot/+/6468 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4795 refactor(tvix/eval): add `initialised` arg to declare_phantomVincent Ambo2-9/+8
There are more upcomming uses of declare_phantom where this will come in handy to avoid some code bloat. Change-Id: I75cad8caf14511c519ab2f56e87e99bcbf0a082e Reviewed-on: https://cl.tvl.fyi/c/depot/+/6467 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4794 refactor(tvix/eval): encapsulate scope cleanup logic in moduleVincent Ambo2-37/+55
Moves the logic for removing tracked locals from a given scope from the compiler's locals list, and leaves only the actual compiler-related stuff (emitting warnings, cleaning up locals at runtime) in the compiler itself. Change-Id: I9da6eb54967f0a7775f624d602fe11be4c7ed5c4 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6466 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4793 fix(tvix/eval): avoid forcing with-target until absolutely necessaryVincent Ambo2-5/+11
Change-Id: I00efbbb8b9d3d22f32becf0919c6adf1be8b4b69 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6465 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4792 refactor(tvix/eval): extract attribute set inherit into helperVincent Ambo1-18/+31
This will be re-used between the code paths for recursive/non-recursive sets, and it might even be possible to unify it with the logic for compiling `let inherit ...`. Change-Id: I960a061048ac583a6e932e11ff6e642d9fc3093e Reviewed-on: https://cl.tvl.fyi/c/depot/+/6464 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4790 feat(tvix/eval): implement "formals" function parametersVincent Ambo2-1/+101
The comment explains how this works fairly well. Note that this does not yet have the ability to check "closed formals", i.e. without an ellipsis Tvix will *NOT* fail if unexpected attribute set keys are provided. Change-Id: I0d2b77e893243093d2789baa57f876d35d0a32ff Reviewed-on: https://cl.tvl.fyi/c/depot/+/6463 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-10 r/4788 fix(tvix/eval): always add history entries in REPLVincent Ambo1-1/+1
... even if the code is broken. Change-Id: I5898bceaebf201b97e8988c94c90e7fafff82529 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6462 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 r/4787 fix(tvix/eval): reintroduce 'InvalidAttribuetName' error variantVincent Ambo2-1/+11
As pointed out by sterni in cl/6205, this is actually possible in syntactically valid expressions like { ${12 + 13} = 12; } Change-Id: Id8a1e3aceb551f288f9050c4eea563eb6572f1a7 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6461 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 r/4786 fix(tvix/eval): fix doc comment syntax where applicableVincent Ambo10-110/+122
As pointed out by grfn on cl/6091 Change-Id: I28308577b7cf99dffb4a4fd3cc8783eb9ab4d0d6 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6460 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 r/4785 feat(tvix/eval): conditionally use tracing/disassembling observersVincent Ambo1-7/+23
Gates the observes behind the envvars `TVIX_DUMP_BYTECODE` and `TVIX_TRACE_RUNTIME`. (hi grfn, yes, we should probably introduce CLI flags soon) Change-Id: I4fa194a84b04593d609b96b44471c3644fb30296 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6459 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 r/4784 feat(tvix/eval): optimise tail calls in emitted chunksVincent Ambo1-2/+20
When the last instruction in a chunk is OpCall, make it an OpTailCall instead. Change-Id: I2c80a06ee85e4abf545887b1a79b6d8b5e6123e9 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6458 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-10 r/4783 feat(tvix/eval): implement OpTailCallVincent Ambo3-9/+50
If the last operation within a chunk is a function call, the call can be executed in the same call frame without increasing the depth of the call stack. To enable this, a new OpTailCall instruction (similar to OpCall) is introduced, but not yet emitted by the compiler. Change-Id: I9ffbd7da6d2d6a8ec7a724646435dc6ee89712f2 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6457 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-09 r/4782 fix(tvix/eval): force value passed to builtins.toStringVincent Ambo2-4/+26
This introduces a macro to do the forcing, but this solution isn't very nice and also does not work in all cases yet. Change-Id: Icd18862ec47edb82c0efc3af5835a6cb6126f629 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6456 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4781 chore(tvix/eval): clean up a stale commentVincent Ambo1-4/+0
Change-Id: If1b02fe1c78398387ea98490e5b099f1ff1b4164 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6455 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4780 chore(tvix/eval): clean up remains of previous disassembler implVincent Ambo3-45/+3
Change-Id: Ib402ea23a58dc52ed0c5a97178cb5d0e53d69300 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6454 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4779 feat(tvix/eval): implement TracingObserver for runtime tracingVincent Ambo1-0/+54
This produces similar output to the previous tracing feature, but can redirect the output somewhere else. Change-Id: I9493c260f480904f3932cb74809b622c24d7be96 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6453 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4778 feat(tvix/eval): implement runtime tracing methods for ObserverVincent Ambo3-30/+44
These methods make it possible to trace the runtime execution of the VM through an observer. Change-Id: I90e26853ba2fe44748613e7f761ed5c1c5fc9ff7 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6452 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4777 refactor(tvix/eval): move `disassemble_op` to the Chunk structureVincent Ambo3-29/+33
Change-Id: Ic6710c609ed647bfa47d673aaf22c4da96c0f319 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6451 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4776 chore(tvix/eval): export some symbols from the crateVincent Ambo1-1/+5
These are required for tvixbolt to work. This interface is definitely not stable yet, though. Change-Id: I4076498e8f42311de74ee4f33c93a3ee0c5f8d3a Reviewed-on: https://cl.tvl.fyi/c/depot/+/6450 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4775 feat(tvix/eval): implement DisassemblingObserver for compilerVincent Ambo6-94/+110
This type implements an observer that is called whenever the compiler emits a chunk (after the toplevel, thunks, or lambdas) and prints the output of the disassembler to its internal writer. This replaces half of the uses of the `disassembler` feature, which has been removed from the Cargo configuration. Note that at this commit runtime tracing is not yet implemented as an observer. Change-Id: I7894ca1ba445761aba4ad51d98e4a7b6445f1aea Reviewed-on: https://cl.tvl.fyi/c/depot/+/6449 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4774 feat(tvix/eval): implement (compilation) observer traitVincent Ambo2-0/+37
This trait will enable library users of tvix-eval to observe internal happenings of the compilation and runtime processes. The initial methods of the observer will be called whenever the compiler emits a chunk. Change-Id: I668f6c2cfe3d6f4c1a1612c0f293831011768437 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6448 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4773 refactor(tvix/eval): index into Chunk with ConstantIdx/CodeIdxVincent Ambo2-8/+22
This is a step towards hiding the internal fields of thunk, and making the interface of the type more predictable. Part of the preparation for implementing observers. Change-Id: I1a88a96419c72eb9e2332b56a2dd94afa47e6f88 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6447 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-09 r/4771 chore(tvix/eval): debug_assert that all jumps are patchedVincent Ambo1-0/+4
Suggestion from sterni in cl/6282 Change-Id: I1adbdda9ff74f55a2f72892ffa524808b305f403 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6445 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-08 r/4770 feat(tvix/eval): thunk binary operations and select expressionsVincent Ambo3-2/+22
With this, most cases of `fix` in attribute sets will work correctly. A simple test exercising both has been added. Change-Id: I70fd431177bb6e48ecb33a87518b050c4c3d1c09 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6437 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4769 fix(tvix/eval): hold thunk borrow as shortly as possibleVincent Ambo1-7/+6
At the point where control flow exits Thunk::force (which may be due to recursing), it is vital that there is no longer a borrow to the inner thunk representation, otherwise this can cause accidental infinite recursion (which will be detected, but cause failures on valid code). Change-Id: I2846f3142830ae3110a4f5d2299e9d7928634504 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6436 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4768 feat(tvix/eval): print lambda memory adresses in disassemblerVincent Ambo4-32/+30
This makes it easier to track exactly which lambda is which when inspecting e.g. the concrete representation of a thunk. At runtime all lambdas live in an Rc. To make this print the right address, the construction of these Rcs had to be moved up right to the point where the lambda is first emitted (and disassembled). Change-Id: I6070e6c8ac55f0bd697966c4e7c5565c20d19106 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6435 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4767 fix(tvix/eval): ensure disassembler prints continous lines correctlyVincent Ambo2-4/+12
There can be different spans on the same line, so the previous implementation would duplicate line numbers unnecessarily. Change-Id: I8d8db77177aee0d834a6ec3584641e1bd5f31c3e Reviewed-on: https://cl.tvl.fyi/c/depot/+/6434 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4766 feat(tvix/eval): thunk function applicationsVincent Ambo1-1/+4
Change-Id: I18065ed234ec104ac74d0e1c2d0937c2d78ca7db Reviewed-on: https://cl.tvl.fyi/c/depot/+/6433 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4765 feat(tvix/eval): thunk creation of listsVincent Ambo1-1/+3
Change-Id: I84b68c5d002ec613d278315bbf49e9839f0fe8e8 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6432 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4764 test(tvix/eval): add test for stack slot accounting edge-caseVincent Ambo2-0/+18
This was fixed by some of the previous commits around scopes. It's somewhat similar to a few other tests, but I had this one failing earlier and everything else succeeding, so it is useful to keep it around for sure. Change-Id: Ie6cf372b5c805daf992cd87aeb3dfe91542c381c Reviewed-on: https://cl.tvl.fyi/c/depot/+/6431 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4763 fix(tvix/eval): address current clippy & grfn lintsVincent Ambo5-38/+32
Change-Id: I65c6feb9f817b5b367d37204a1f57acfe4100d97 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6430 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4762 fix(tvix/eval): consider local depth when deciding to deferVincent Ambo3-5/+19
Deferred local upvalues can *only* occur at the same depth as the thing that is closing over them, but there are various situations with scope nesting where the actual stack indexes of the local and the closer look like a deferred value is being accessed. To fix this, simply compare the depth as well. Change-Id: Ice77424cc87ab0a2c4f01379e68d4399a917b12b Reviewed-on: https://cl.tvl.fyi/c/depot/+/6429 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4761 chore(tvix/eval): remove accidentally duplicated testVincent Ambo2-3/+0
This is the same as `eval-okay-attrs-simple-inherit`. Change-Id: I23878accc6cd62c16ec96601239838a385d31306 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6428 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4760 refactor(tvix/eval): clean up logic in Compiler::end_scopeVincent Ambo1-5/+3
The condition here was extremely hard to read prior to this change. As the locals vector is now guaranteed to never be empty (there is always at least a phantom for the current chunk's root expression), the logic here can be simplified to just dropping tailing locals entries while their depth matches that of the scope being closed. Change-Id: I24973e23bc2ad25e62ece64ab4d8624e6e274c16 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6427 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4759 fix(tvix/eval): set up root stack slot in closures & thunksVincent Ambo1-4/+8
Similar to setting up a phantom slot when compiling the root value of a file, closures and thunks need to have a phantom stack slot for the root of the expression yielded by their thunk to make all accounting work correctly. The tricky thing here is that closures & thunks *escape* their inner lambda context (that's the point!), so the functions emitting them need to know both the *inner* slot (to resolve everything correctly while compiling the slot) and the *outer* slot (to correctly emit instructions for closing over upvalues). Change-Id: I62ac58e2f639c4b9e09cc702bdbfd2373e985d7f Reviewed-on: https://cl.tvl.fyi/c/depot/+/6426 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4758 fix(tvix/eval): only pop initialised locals when closing scopesVincent Ambo1-5/+10
This avoids emitting OpPop instructions for locals that only existed virtually (as uninitialised phantoms). Change-Id: I8105afcca80c3f7b7ef93ce5e2f0d08a93f4ad27 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6425 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4757 fix(tvix/eval): ensure that root stack slot actually existsVincent Ambo2-5/+3
Instead of using a sentinel LocalIdx which potentially points to a value in the locals stack that does not actually exist, set up an initial uninitialised phantom value representing the result of the root expression. Change-Id: I82ea774daab83168020a3850bed57d35ab25c7df Reviewed-on: https://cl.tvl.fyi/c/depot/+/6424 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4756 fix(tvix/eval): compare *stack* slots when deciding whether to deferVincent Ambo2-2/+3
When deciding whether an upvalue needs to have a deferred resolution step, the *stack* indexes should be compared - not the locals indexes. The results are almost always the same, but there are tricky situations where this can cause errors. It's difficult to reproduce these errors in isolation, as they depend on other scope behaviour, so this is one in a series of commits to address the combination of issues which will gain some tests at the end. Change-Id: Iaa400b8d9500af58f493ab10e4f95022f3b5dd21 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6423 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4755 fix(tvix/eval): propagate scope depth when nesting scopesVincent Ambo1-0/+1
Change-Id: Id441646db550f6195c2e247a0afbb5c9d91da8a0 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6422 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4754 refactor(tvix/eval): refactor locals to use an enum for phantomsVincent Ambo2-22/+48
Instead of using sentinel values and an additional bool, this tracks the identifier of a local as an enum that is either a statically known name, or a phantom. To make this work correctly some more locals related logic has been encapsulated in the `scope` module, which is a good thing (that's the goal). Phantom values are now not initialised by default, but the only current call site of phantoms (`with` expression compilation) performs the initialisation right away. This commit changes no actual functionality right now, but paves the way for fixing an issue related to `let` bodies. Change-Id: I679f93a59a4daeacfe40f4012263cfb7bc05034e Reviewed-on: https://cl.tvl.fyi/c/depot/+/6421 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4753 refactor(tvix/eval): always pass slot to compiler methodsVincent Ambo2-33/+32
The slot is now always known (at the root of the file it is simply stack slot 0 once the scope drops back down to 0), so it does not need to be wrapped in an `Option` and accessed in cumbersome ways anymore. Change-Id: I46bf67a4cf5cb96e4874dffd0e3fb07c551d44f0 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6420 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4752 refactor(tvix/eval): implement much clearer disassembler outputVincent Ambo2-26/+50
With this change the runtime trace contains much more exact information about the context of the computation (entering/exiting calls etc.) This is in large part due to moving the tracer to be a field on the VM itself, which enables consistent ordering of traces across the execution, and tracing an execution with its *input* instead of *output* stack. Change-Id: Ibe525e6e7d869756501e52bef1a441619ce7332c Reviewed-on: https://cl.tvl.fyi/c/depot/+/6419 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4751 chore(tvix/eval): print value when panicking on internalsVincent Ambo1-1/+3
This makes it much easier to figure out what happened while debugging this sort of thing. Change-Id: I2e0e8096709adc647d63c04f213c547c415e5f44 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6418 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4750 fix(tvix/eval): force argument of builtins.lengthVincent Ambo1-1/+4
Change-Id: Iaf94dfc7cb058f5c1c311066d92e01512e09cf71 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6417 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
2022-09-08 r/4749 fix(tvix/eval): don't panic when printing a black holeVincent Ambo1-2/+6
This could occur when the disassembler is enabled and tracing the runtime while a thunk is being evaluated, as it would not be possible for the *tracer* to borrow the thunk at this exact moment. However, we know that if the borrowing fails here we are dealing with a not-fully evaluated thunk (blackhole), which should just print the internal representation. Change-Id: I4bdb4f17818d55795368e3d28842048f488f0a91 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6416 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI