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2022-09-11 r/4810 refactor(tvix/eval): move attrset-related code to compiler::attrsVincent Ambo2-202/+209
There's about to be a lot more code for attrsets (hopefully temporarily as part of an expand&contract cycle), while nested attribute logic is being refactored in preparation for recursive attribute sets. This does not change any functionality. Change-Id: I667565cd810ca7d9046120d1721c2ceb9095550b Reviewed-on: https://cl.tvl.fyi/c/depot/+/6497 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4809 fix(tvix/eval): place plain inherits in correct stack slotssterni3-27/+62
We need to make sure that we compile all plain inherits in a let expression before declaring any other locals. Plain inherits are special in the sense that they can never be recursive, instead resolving to a higher scope. Thus we need to compile their value, before declaring them. If we don't do that, before any other local can be declared, we cause a situation where the plain inherits' values are placed into other locals' stack slots. Note that we can't integrate the plain inherit compilation into the regular 2-3 phase model where we defer the compilation of the value or we'd compile `let inherit x; in …` as `let x = x; in …`. Change-Id: I951d5df3c9661a054e12401546875f4685b5bf08 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6496 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4808 test(tvix/eval): add test for mutually recursive let bindingssterni2-0/+15
This test shows that let bindings' dependencies can form a cyclical graph, so we need to use thunking to break this cycle. Change-Id: I2a4de71fd7024f3d3d1166154784139a82f39411 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6495 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4807 fix(tvix/eval): wrap asserts in a thunksterni3-1/+12
As the new test case demonstrates, asserts need to be evaluated lazily. Change-Id: I808046722c5a504e9497855ca5026d255c7a4c34 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6494 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4806 test(tvix/eval): test “useful” plain inheritssterni2-0/+10
Change-Id: Ic4700f0618a393e45a2ee7c70045edff97e30c49 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6493 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4805 fix(tvix/eval): declare let inherit (from) locals before compilingsterni5-49/+69
The recent change that split declaration of let based locals and the compilation of their values did not touch locals bound by inherit in let. These were previously declared and compiled immediately before starting to work on the other locals introduced in a let. In the case of plain inherits, this behavior is kept in this change, because there's nothing wrong with it: The value of a plain inherit will always resolve to a higher scope, either statically or dynamically. Since inherit (from) expression might refer to other locals bound in the same let, we need to handle them in the same three steps as ordinary let based locals: 1. We need to declare the (uninitialised) locals. 2. We need to compile the expression that obtains their value. For this, we create a new thunk, since the from expression may very well return a thunk which we need to force before selecting the value we are interested in. 3. Thunks need to be finalised. For 1., we create an extra pass over the inherits that already declares and initialises plain inherits and notes inherit (from) expressions in the entries vector after declaring them. 2. only needs a bit of adapting to create the thunks for selecting if appropriate, the rest of the existing code can be reused. Change-Id: Ie4ac1c0f9ffcbf7c07c452036aa8e577443af773 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6490 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org> Reviewed-by: tazjin <tazjin@tvl.su>
2022-09-11 r/4804 docs(tvix/eval): add some notes on recursive attribute setsVincent Ambo1-0/+60
Change-Id: I36b826f12854a22e60a27ed1982ab5528c58bdad Reviewed-on: https://cl.tvl.fyi/c/depot/+/6489 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4803 docs(tvix/eval): add optimisation note on eliminating `with` thunksVincent Ambo1-6/+9
Change-Id: I18d50ac8e157929a027f8bf284e65f1eb8950d5a Reviewed-on: https://cl.tvl.fyi/c/depot/+/6488 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
2022-09-11 r/4802 fix(tvix/eval): thunk all uses of `with`Vincent Ambo5-1/+22
With this all other "weird scope" logic starts working for `with` as well. Change-Id: I0ea1d8c5fbd9cec5084bd574224f77b71ff2b487 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6487 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
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
2022-09-11 r/4789 chore(tvix): remove stale .envrcVincent Ambo1-10/+0
This doesn't actually do anything other than causing errors for the current state of this folder. Change-Id: I0af6410e9eb1700cd0b2b105c8adde077d931a69 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6492 Autosubmit: tazjin <tazjin@tvl.su> Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
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 Ambo7-98/+111
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/4772 chore(tvix/eval): gate REPL-only dependencies behind `repl` featureVincent Ambo1-1/+13
With this change, it becomes possible to compile tvix-eval to webassembly if the `repl` feature is disabled. Change-Id: Icc0a059964cd0bea2054110c682d50fc5c87ec01 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6446 Tested-by: BuildkiteCI Reviewed-by: sterni <sternenseemann@systemli.org>
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