var => let in specs/ and tests/ (#3425)

beacon_chain/spec/beaconstate.nim

@@ -689,7 +689,7 @@ proc process_attestation*(
     # The genericSeqAssign generated by the compiler to copy the attestation
     # data sadly is a processing hotspot - the business with the addDefault
     # pointer is here simply to work around the poor codegen
-    var pa = attestations.addDefault()
+    let pa = attestations.addDefault()
     if pa.isNil:
       return err("process_attestation: too many pending attestations")
     assign(pa[].aggregation_bits, attestation.aggregation_bits)
@@ -807,7 +807,7 @@ func upgrade_to_altair*(cfg: RuntimeConfig, pre: phase0.BeaconState):
   doAssert inactivity_scores.data.setLen(pre.validators.len)
   inactivity_scores.resetCache()
 
-  var post = (ref altair.BeaconState)(
+  let post = (ref altair.BeaconState)(
     genesis_time: pre.genesis_time,
     genesis_validators_root: pre.genesis_validators_root,
     slot: pre.slot,

beacon_chain/spec/digest.nim

@@ -66,7 +66,7 @@ func eth2digest*(v: openArray[byte]): Eth2Digest {.noinit.} =
   else:
     # We use the init-update-finish interface to avoid
     # the expensive burning/clearing memory (20~30% perf)
-    var ctx: Eth2DigestCtx
+    let ctx: Eth2DigestCtx
     ctx.init()
     ctx.update(v)
     ctx.finish()
@@ -93,7 +93,7 @@ template withEth2Hash*(body: untyped): Eth2Digest =
         res
     else:
       block:
-        var h  {.inject, noinit.}: Eth2DigestCtx
+        let h  {.inject, noinit.}: Eth2DigestCtx
         init(h)
         body
         finish(h)

beacon_chain/spec/presets.nim

@@ -418,7 +418,7 @@ proc readRuntimeConfig*(
     if line.len == 0 or line[0] == '#': continue
     # remove any trailing comments
     let line = line.split("#")[0]
-    var lineParts = line.split(":")
+    let lineParts = line.split(":")
     if lineParts.len != 2:
       fail "Invalid syntax: A preset file should include only assignments in the form 'ConstName: Value'"
 

beacon_chain/spec/state_transition.nim

@@ -157,7 +157,7 @@ func maybeUpgradeStateToAltair(
   # once by checking for existing fork.
   if getStateField(state, slot).epoch == cfg.ALTAIR_FORK_EPOCH and
       state.kind == BeaconStateFork.Phase0:
-    var newState = upgrade_to_altair(cfg, state.phase0Data.data)
+    let newState = upgrade_to_altair(cfg, state.phase0Data.data)
     state = (ref ForkedHashedBeaconState)(
       kind: BeaconStateFork.Altair,
       altairData: altair.HashedBeaconState(
@@ -169,7 +169,7 @@ func maybeUpgradeStateToBellatrix(
   # once by checking for existing fork.
   if getStateField(state, slot).epoch == cfg.BELLATRIX_FORK_EPOCH and
       state.kind == BeaconStateFork.Altair:
-    var newState = upgrade_to_bellatrix(cfg, state.altairData.data)
+    let newState = upgrade_to_bellatrix(cfg, state.altairData.data)
     state = (ref ForkedHashedBeaconState)(
       kind: BeaconStateFork.Bellatrix,
       bellatrixData: bellatrix.HashedBeaconState(

tests/consensus_spec/altair/test_fixture_merkle_single_proof.nim

@@ -37,7 +37,7 @@ proc runTest(identifier: string) =
 
       let
         proof = block:
-          var s = openFileStream(testDir/"proof.yaml")
+          let s = openFileStream(testDir/"proof.yaml")
           defer: close(s)
           var res: TestProof
           yaml.load(s, res)

tests/consensus_spec/altair/test_fixture_operations.nim

@@ -52,7 +52,7 @@ proc runTest[T, U](
         "[Invalid] "
 
     test prefix & baseDescription & testSuiteName & " - " & identifier:
-      var preState = newClone(
+      let preState = newClone(
         parseTest(testDir/"pre.ssz_snappy", SSZ, altair.BeaconState))
       let done = applyProc(
         preState[], parseTest(testDir/(applyFile & ".ssz_snappy"), SSZ, T))

tests/consensus_spec/altair/test_fixture_ssz_consensus_objects.nim

@@ -71,7 +71,7 @@ proc checkSSZ(T: type, dir: string, expectedHash: SSZHashTreeRoot) =
   # TODO check the value (requires YAML loader)
 
 proc loadExpectedHashTreeRoot(dir: string): SSZHashTreeRoot =
-  var s = openFileStream(dir/"roots.yaml")
+  let s = openFileStream(dir/"roots.yaml")
   yaml.load(s, result)
   s.close()
 

tests/consensus_spec/altair/test_fixture_state_transition_epoch.nim

@@ -31,7 +31,7 @@ template runSuite(
       test testName & " - " & unitTestName & preset():
         # BeaconState objects are stored on the heap to avoid stack overflow
         type T = altair.BeaconState
-        var preState {.inject.} = newClone(parseTest(testDir/"pre.ssz_snappy", SSZ, T))
+        let preState {.inject.} = newClone(parseTest(testDir/"pre.ssz_snappy", SSZ, T))
         let postState = newClone(parseTest(testDir/"post.ssz_snappy", SSZ, T))
         var cache {.inject, used.} = StateCache()
         template state: untyped {.inject, used.} = preState[]

tests/consensus_spec/altair/test_fixture_sync_protocol.nim

@@ -94,7 +94,7 @@ suite "EF - Altair - Unittests - Sync protocol" & preset():
 
   # https://github.com/ethereum/consensus-specs/blob/v1.1.9/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py#L36-L90
   test "test_process_light_client_update_not_timeout":
-    var forked = assignClone(genesisState[])
+    let forked = assignClone(genesisState[])
     template state: untyped {.inject.} = forked[].altairData.data
     var store = initialize_light_client_store(state)
 
@@ -146,7 +146,7 @@ suite "EF - Altair - Unittests - Sync protocol" & preset():
 
   # https://github.com/ethereum/consensus-specs/blob/v1.1.9/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py#L93-L154
   test "process_light_client_update_timeout":
-    var forked = assignClone(genesisState[])
+    let forked = assignClone(genesisState[])
     template state: untyped {.inject.} = forked[].altairData.data
     var store = initialize_light_client_store(state)
 
@@ -207,7 +207,7 @@ suite "EF - Altair - Unittests - Sync protocol" & preset():
 
   # https://github.com/ethereum/consensus-specs/blob/v1.1.9/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py#L157-L224
   test "process_light_client_update_finality_updated":
-    var forked = assignClone(genesisState[])
+    let forked = assignClone(genesisState[])
     template state: untyped {.inject.} = forked[].altairData.data
     var store = initialize_light_client_store(state)
 

tests/consensus_spec/altair/test_fixture_transition.nim

@@ -36,7 +36,7 @@ proc runTest(testName, testDir, unitTestName: string) =
   let testPath = testDir / unitTestName
 
   var transitionInfo: TransitionInfo
-  var s = openFileStream(testPath/"meta.yaml")
+  let s = openFileStream(testPath/"meta.yaml")
   defer: close(s)
   yaml.load(s, transitionInfo)
 

tests/consensus_spec/bellatrix/test_fixture_fork.nim

@@ -31,7 +31,7 @@ proc runTest(identifier: string) =
         postState = newClone(
           parseTest(testDir/"post.ssz_snappy", SSZ, bellatrix.BeaconState))
 
-      var cfg = defaultRuntimeConfig
+      let cfg = defaultRuntimeConfig
 
       let upgradedState = upgrade_to_bellatrix(cfg, preState[])
       check: upgradedState[].hash_tree_root() == postState[].hash_tree_root()

tests/consensus_spec/bellatrix/test_fixture_operations.nim

@@ -53,7 +53,7 @@ proc runTest[T, U](
         "[Invalid] "
 
     test prefix & baseDescription & testSuiteName & " - " & identifier:
-      var preState = newClone(
+      let preState = newClone(
         parseTest(testDir/"pre.ssz_snappy", SSZ, bellatrix.BeaconState))
       let done = applyProc(
         preState[], parseTest(testDir/(applyFile & ".ssz_snappy"), SSZ, T))

tests/consensus_spec/bellatrix/test_fixture_ssz_consensus_objects.nim

@@ -71,7 +71,7 @@ proc checkSSZ(T: type, dir: string, expectedHash: SSZHashTreeRoot) =
   # TODO check the value (requires YAML loader)
 
 proc loadExpectedHashTreeRoot(dir: string): SSZHashTreeRoot =
-  var s = openFileStream(dir/"roots.yaml")
+  let s = openFileStream(dir/"roots.yaml")
   yaml.load(s, result)
   s.close()
 

tests/consensus_spec/bellatrix/test_fixture_state_transition_epoch.nim

@@ -30,7 +30,7 @@ template runSuite(
       test testName & " - " & unitTestName & preset():
         # BeaconState objects are stored on the heap to avoid stack overflow
         type T = bellatrix.BeaconState
-        var preState {.inject.} = newClone(parseTest(testDir/"pre.ssz_snappy", SSZ, T))
+        let preState {.inject.} = newClone(parseTest(testDir/"pre.ssz_snappy", SSZ, T))
         let postState = newClone(parseTest(testDir/"post.ssz_snappy", SSZ, T))
         var cache {.inject, used.} = StateCache()
         template state: untyped {.inject, used.} = preState[]

tests/consensus_spec/bellatrix/test_fixture_transition.nim

@@ -36,7 +36,7 @@ proc runTest(testName, testDir, unitTestName: string) =
   let testPath = testDir / unitTestName
 
   var transitionInfo: TransitionInfo
-  var s = openFileStream(testPath/"meta.yaml")
+  let s = openFileStream(testPath/"meta.yaml")
   defer: close(s)
   yaml.load(s, transitionInfo)
 

tests/consensus_spec/fixtures_utils.nim

@@ -67,7 +67,7 @@ template readFileBytes*(path: string): seq[byte] =
   cast[seq[byte]](readFile(path))
 
 proc sszDecodeEntireInput*(input: openArray[byte], Decoded: type): Decoded =
-  var stream = unsafeMemoryInput(input)
+  let stream = unsafeMemoryInput(input)
   var reader = init(SszReader, stream)
   reader.readValue(result)
 

tests/consensus_spec/phase0/test_fixture_operations.nim

@@ -50,7 +50,7 @@ proc runTest[T, U](
         "[Invalid] "
 
     test prefix & baseDescription & testSuiteName & " - " & identifier:
-      var preState = newClone(
+      let preState = newClone(
         parseTest(testDir/"pre.ssz_snappy", SSZ, phase0.BeaconState))
       let done = applyProc(
         preState[], parseTest(testDir/(applyFile & ".ssz_snappy"), SSZ, T))

tests/consensus_spec/phase0/test_fixture_ssz_consensus_objects.nim

@@ -71,7 +71,7 @@ proc checkSSZ(T: type, dir: string, expectedHash: SSZHashTreeRoot) =
   # TODO check the value (requires YAML loader)
 
 proc loadExpectedHashTreeRoot(dir: string): SSZHashTreeRoot =
-  var s = openFileStream(dir/"roots.yaml")
+  let s = openFileStream(dir/"roots.yaml")
   yaml.load(s, result)
   s.close()
 

tests/consensus_spec/phase0/test_fixture_state_transition_epoch.nim

@@ -30,7 +30,7 @@ template runSuite(suiteDir, testName: string, transitionProc: untyped): untyped
       test testName & " - " & unitTestName & preset():
         # BeaconState objects are stored on the heap to avoid stack overflow
         type T = phase0.BeaconState
-        var preState {.inject.} = newClone(parseTest(testDir/"pre.ssz_snappy", SSZ, T))
+        let preState {.inject.} = newClone(parseTest(testDir/"pre.ssz_snappy", SSZ, T))
         let postState = newClone(parseTest(testDir/"post.ssz_snappy", SSZ, T))
         var cache {.inject, used.} = StateCache()
         var info {.inject.}: EpochInfo

tests/consensus_spec/test_fixture_fork_choice.nim

@@ -266,7 +266,7 @@ proc runTest(path: string, fork: BeaconBlockFork) =
   defer:
     db.close()
 
-  var stores = case fork
+  let stores = case fork
     of BeaconBlockFork.Phase0:
       initialLoad(
         path, db,

tests/consensus_spec/test_fixture_ssz_generic_types.nim

@@ -84,8 +84,8 @@ type
 proc checkBasic(T: typedesc,
                 dir: string,
                 expectedHash: SSZHashTreeRoot) =
-  var fileContents = snappy.decode(readFileBytes(dir/"serialized.ssz_snappy"), MaxObjectSize)
+  let fileContents = snappy.decode(readFileBytes(dir/"serialized.ssz_snappy"), MaxObjectSize)
-  var deserialized = newClone(sszDecodeEntireInput(fileContents, T))
+  let deserialized = newClone(sszDecodeEntireInput(fileContents, T))
 
   let expectedHash = expectedHash.root
   let actualHash = "0x" & toLowerASCII($hash_tree_root(deserialized[]))
@@ -106,10 +106,10 @@ macro testVector(typeIdent: string, size: int): untyped =
   let types = ["bool", "uint8", "uint16", "uint32", "uint64", "uint128", "uint256"]
   let sizes = [1, 2, 3, 4, 5, 8, 16, 31, 512, 513]
 
-  var dispatcher = nnkIfStmt.newTree()
+  let dispatcher = nnkIfStmt.newTree()
   for t in types:
     # if typeIdent == t // elif typeIdent == t
-    var sizeDispatch = nnkIfStmt.newTree()
+    let sizeDispatch = nnkIfStmt.newTree()
     for s in sizes:
       # if size == s // elif size == s
       let T = nnkBracketExpr.newTree(
@@ -119,7 +119,7 @@ macro testVector(typeIdent: string, size: int): untyped =
         of "uint256": ident("UInt256")
         else: ident(t)
       )
-      var testStmt = quote do:
+      let testStmt = quote do:
         checkBasic(`T`, dir, expectedHash)
       sizeDispatch.add nnkElifBranch.newTree(
         newCall(ident"==", size, newLit(s)),
@@ -196,7 +196,7 @@ proc sszCheck(baseDir, sszType, sszSubType: string) =
   # Hash tree root
   var expectedHash: SSZHashTreeRoot
   if fileExists(dir/"meta.yaml"):
-    var s = openFileStream(dir/"meta.yaml")
+    let s = openFileStream(dir/"meta.yaml")
     defer: close(s)
     yaml.load(s, expectedHash)
 

tests/fork_choice/scenarios/ffg_01.nim

@@ -8,7 +8,7 @@
 # import ../interpreter # included to be able to use "suite"
 
 func setup_finality_01(): tuple[fork_choice: ForkChoiceBackend, ops: seq[Operation]] =
-  var balances = @[Gwei(1), Gwei(1)]
+  let balances = @[Gwei(1), Gwei(1)]
   let GenesisRoot = fakeHash(0)
 
   # Initialize the fork choice context

tests/fork_choice/scenarios/ffg_02.nim

@@ -8,7 +8,7 @@
 # import ../interpreter # included to be able to use "suite"
 
 func setup_finality_02(): tuple[fork_choice: ForkChoiceBackend, ops: seq[Operation]] =
-  var balances = @[Gwei(1), Gwei(1)]
+  let balances = @[Gwei(1), Gwei(1)]
   let GenesisRoot = fakeHash(0)
 
   # Initialize the fork choice context

tests/spec_block_processing/test_process_deposits.nim

@@ -32,7 +32,7 @@ suite "[Unit - Spec - Block processing] Deposits " & preset():
   template valid_deposit(deposit_amount: uint64, name: string): untyped =
     test "Deposit " & name & " MAX_EFFECTIVE_BALANCE balance (" &
           $(MAX_EFFECTIVE_BALANCE div 10'u64^9) & " ETH)":
-      var state = assignClone(genesisState[])
+      let state = assignClone(genesisState[])
 
       # Test configuration
       # ----------------------------------------
@@ -73,7 +73,7 @@ suite "[Unit - Spec - Block processing] Deposits " & preset():
   valid_deposit(MAX_EFFECTIVE_BALANCE + 1, "over")
 
   test "Validator top-up":
-    var state = assignClone(genesisState[])
+    let state = assignClone(genesisState[])
 
     # Test configuration
     # ----------------------------------------
@@ -113,12 +113,12 @@ suite "[Unit - Spec - Block processing] Deposits " & preset():
   template invalid_signature(deposit_amount: uint64, name: string): untyped =
     test "Invalid deposit " & name & " MAX_EFFECTIVE_BALANCE balance (" &
           $(MAX_EFFECTIVE_BALANCE div 10'u64^9) & " ETH)":
-      var state = assignClone(genesisState[])
+      let state = assignClone(genesisState[])
 
       # Test configuration
       # ----------------------------------------
       let validator_index = state.data.validators.len
-      var deposit = mockUpdateStateForNewDeposit(
+      let deposit = mockUpdateStateForNewDeposit(
                       state.data,
                       uint64 validator_index,
                       deposit_amount,

tests/spec_epoch_processing/test_process_justification_and_finalization.nim

@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2018-2021 Status Research & Development GmbH
+# Copyright (c) 2018-2022 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -222,7 +222,7 @@ proc payload =
     doAssert getStateField(genesisState[], validators).lenu64 == NumValidators
 
     setup:
-      var state = assignClone(genesisState[])
+      let state = assignClone(genesisState[])
 
     test " Rule I - 234 finalization with enough support":
       finalizeOn234(state[], Epoch 5, sufficient_support = true)

tests/test_attestation_pool.nim

@@ -253,7 +253,7 @@ suite "Attestation pool processing" & preset():
 
       for j in 0..<bc0.len():
         root.data[8..<16] = toBytesBE(j.uint64)
-        var att = makeAttestation(state[].data, root, bc0[j], cache)
+        let att = makeAttestation(state[].data, root, bc0[j], cache)
         pool[].addAttestation(
           att, @[bc0[j]], att.loadSig, att.data.slot.start_beacon_time)
         inc attestations

tests/test_beacon_chain_db.nim

@@ -92,7 +92,7 @@ suite "Beacon chain DB" & preset():
       db.getPhase0Block(Eth2Digest()).isNone
 
   test "sanity check phase 0 blocks" & preset():
-    var db = BeaconChainDB.new("", inMemory = true)
+    let db = BeaconChainDB.new("", inMemory = true)
 
     let
       signedBlock = withDigest((phase0.TrustedBeaconBlock)())
@@ -131,7 +131,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check Altair blocks" & preset():
-    var db = BeaconChainDB.new("", inMemory = true)
+    let db = BeaconChainDB.new("", inMemory = true)
 
     let
       signedBlock = withDigest((altair.TrustedBeaconBlock)())
@@ -170,7 +170,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check Bellatrix blocks" & preset():
-    var db = BeaconChainDB.new("", inMemory = true)
+    let db = BeaconChainDB.new("", inMemory = true)
 
     let
       signedBlock = withDigest((bellatrix.TrustedBeaconBlock)())
@@ -209,7 +209,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check phase 0 states" & preset():
-    var db = makeTestDB(SLOTS_PER_EPOCH)
+    let db = makeTestDB(SLOTS_PER_EPOCH)
 
     for state in testStatesPhase0:
       let root = state[].phase0Data.root
@@ -227,7 +227,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check Altair states" & preset():
-    var db = makeTestDB(SLOTS_PER_EPOCH)
+    let db = makeTestDB(SLOTS_PER_EPOCH)
 
     for state in testStatesAltair:
       let root = state[].altairData.root
@@ -245,7 +245,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check Bellatrix states" & preset():
-    var db = makeTestDB(SLOTS_PER_EPOCH)
+    let db = makeTestDB(SLOTS_PER_EPOCH)
 
     for state in testStatesBellatrix:
       let root = state[].bellatrixData.root
@@ -263,7 +263,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check phase 0 states, reusing buffers" & preset():
-    var db = makeTestDB(SLOTS_PER_EPOCH)
+    let db = makeTestDB(SLOTS_PER_EPOCH)
     let stateBuffer = (phase0.BeaconStateRef)()
 
     for state in testStatesPhase0:
@@ -283,7 +283,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check Altair states, reusing buffers" & preset():
-    var db = makeTestDB(SLOTS_PER_EPOCH)
+    let db = makeTestDB(SLOTS_PER_EPOCH)
     let stateBuffer = (altair.BeaconStateRef)()
 
     for state in testStatesAltair:
@@ -303,7 +303,7 @@ suite "Beacon chain DB" & preset():
     db.close()
 
   test "sanity check Bellatrix states, reusing buffers" & preset():
-    var db = makeTestDB(SLOTS_PER_EPOCH)
+    let db = makeTestDB(SLOTS_PER_EPOCH)
     let stateBuffer = (bellatrix.BeaconStateRef)()
 
     for state in testStatesBellatrix:

tests/test_blockchain_dag.nim

@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2018-2021 Status Research & Development GmbH
+# Copyright (c) 2018-2022 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -224,7 +224,7 @@ suite "Block pool processing" & preset():
       bs1_3 = b1Add[].atSlot(3.Slot)
       bs2_3 = b2Add[].atSlot(3.Slot)
 
-    var tmpState = assignClone(dag.headState)
+    let tmpState = assignClone(dag.headState)
 
     # move to specific block
     var cache = StateCache()
@@ -461,7 +461,7 @@ suite "chain DAG finalization tests" & preset():
       getStateRoot(dag2.headState.data) == getStateRoot(dag.headState.data)
 
   test "orphaned epoch block" & preset():
-    var prestate = (ref ForkedHashedBeaconState)(kind: BeaconStateFork.Phase0)
+    let prestate = (ref ForkedHashedBeaconState)(kind: BeaconStateFork.Phase0)
     for i in 0 ..< SLOTS_PER_EPOCH:
       if i == SLOTS_PER_EPOCH - 1:
         assign(prestate[], dag.headState.data)
@@ -512,7 +512,7 @@ suite "chain DAG finalization tests" & preset():
         defaultRuntimeConfig, dag.headState.data, Slot(SLOTS_PER_EPOCH * 6 + 2),
         cache, info, {}).isOk()
 
-    var blck = makeTestBlock(
+    let blck = makeTestBlock(
       dag.headState.data, cache,
       attestations = makeFullAttestations(
         dag.headState.data, dag.head.root, getStateField(dag.headState.data, slot),
@@ -628,7 +628,7 @@ suite "Diverging hardforks":
 
     let validatorMonitorAltair = newClone(ValidatorMonitor.init())
 
-    var dagAltair = init(
+    let dagAltair = init(
       ChainDAGRef, altairRuntimeConfig, db, validatorMonitorAltair, {})
     discard AttestationPool.init(dagAltair, quarantine)
 
@@ -660,7 +660,7 @@ suite "Diverging hardforks":
 
     let validatorMonitor = newClone(ValidatorMonitor.init())
 
-    var dagAltair = init(
+    let dagAltair = init(
       ChainDAGRef, altairRuntimeConfig, db, validatorMonitor, {})
     discard AttestationPool.init(dagAltair, quarantine)
 

tests/test_gossip_validation.nim

@@ -243,7 +243,7 @@ suite "Gossip validation - Extra": # Not based on preset config
 
     let
       contribution = block:
-        var contribution = (ref SignedContributionAndProof)()
+        let contribution = (ref SignedContributionAndProof)()
         check: syncCommitteeMsgPool[].produceContribution(
           slot, state[].root, subcommitteeIdx,
           contribution.message.contribution)

tests/test_keystore.nim

@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2018-2021 Status Research & Development GmbH
+# Copyright (c) 2018-2022 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -288,7 +288,7 @@ suite "KeyStorage testing suite":
     checkVariant "75ea" # checksum
     checkVariant "b722" # cipher
 
-    var badKdf = parseJson(pbkdf2Vector)
+    let badKdf = parseJson(pbkdf2Vector)
     badKdf{"crypto", "kdf", "function"} = %"invalid"
 
     check decryptKeystore(JsonString $badKdf,
@@ -296,7 +296,7 @@ suite "KeyStorage testing suite":
 
 suite "eth2.0-deposits-cli compatibility":
   test "restoring mnemonic without password":
-    var mnemonic = Mnemonic "camera dad smile sail injury warfare grid kiwi report minute fold slot before stem firm wet vague shove version medal one alley vibrant mushroom"
+    let mnemonic = Mnemonic "camera dad smile sail injury warfare grid kiwi report minute fold slot before stem firm wet vague shove version medal one alley vibrant mushroom"
     let seed = getSeed(mnemonic, KeystorePass.init "")
     check byteutils.toHex(distinctBase seed) == "60043d6e1efe0eea2ef1c8e7d4bb2d79cb27d3403e992b6058998c27c373cfb6fe047b11405360bb224803726fd6b0ee9e3335ae7d9032e6cb49baf08697cf2a"
 
@@ -324,7 +324,7 @@ suite "eth2.0-deposits-cli compatibility":
       v3WK.toHex == "56b158b3b170e9c339b94b895afc28964a0b6d7a0809a39b558ca8b6688487cd"
 
   test "restoring mnemonic with password":
-    var mnemonic = Mnemonic "swear umbrella lesson couch void gentle rocket valley distance match floor rocket flag solve muscle common modify target city youth pottery predict flip ghost"
+    let mnemonic = Mnemonic "swear umbrella lesson couch void gentle rocket valley distance match floor rocket flag solve muscle common modify target city youth pottery predict flip ghost"
     let seed = getSeed(mnemonic, KeystorePass.init "abracadabra!@#$%^7890")
     check byteutils.toHex(distinctBase seed) == "f129c3ac003a07e54974d8dbeb08d20c2343fc516e0e3704570c500a4b6ed98bad2e6fec6a3b9a88076c17feaa0d01163855578cb08bae53860d0ae2558cf03e"
 

tests/test_statediff.nim

@@ -1,5 +1,5 @@
 # beacon_chain
-# Copyright (c) 2018-2021 Status Research & Development GmbH
+# Copyright (c) 2018-2022 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -35,7 +35,7 @@ suite "state diff tests" & preset():
           getStateField(testStates[j][], slot)
         if getStateField(testStates[i][], slot) + SLOTS_PER_EPOCH != getStateField(testStates[j][], slot):
           continue
-        var tmpStateApplyBase = assignClone(testStates[i].altairData.data)
+        let tmpStateApplyBase = assignClone(testStates[i].altairData.data)
         let diff = diffStates(
           testStates[i].altairData.data, testStates[j].altairData.data)
         # Immutable parts of validators stored separately, so aren't part of

tests/testblockutil.nim

@@ -149,7 +149,7 @@ proc makeTestBlock*(
   # It's a bit awkward - in order to produce a block for N+1, we need to
   # calculate what the state will look like after that block has been applied,
   # because the block includes the state root.
-  var tmpState = assignClone(state)
+  let tmpState = assignClone(state)
   addTestBlock(
     tmpState[], cache, eth1_data,
     attestations, deposits, sync_aggregate, graffiti, cfg = cfg)