feat: require type annotations for loop variables

examples/auctions/blind_auction.vy

@@ -107,7 +107,7 @@ def reveal(_numBids: int128, _values: uint256[128], _fakes: bool[128], _secrets:
 
     # Calculate refund for sender
     refund: uint256 = 0
-    for i in range(MAX_BIDS):
+    for i: int128 in range(MAX_BIDS):
         # Note that loop may break sooner than 128 iterations if i >= _numBids
         if (i >= _numBids):
             break

examples/tokens/ERC1155ownable.vy

@@ -205,7 +205,7 @@ def balanceOfBatch(accounts: DynArray[address, BATCH_SIZE], ids: DynArray[uint25
     assert len(accounts) == len(ids), "ERC1155: accounts and ids length mismatch"
     batchBalances: DynArray[uint256, BATCH_SIZE] = []
     j: uint256 = 0
-    for i in ids:
+    for i: uint256 in ids:
         batchBalances.append(self.balanceOf[accounts[j]][i])
         j += 1
     return batchBalances
@@ -243,7 +243,7 @@ def mintBatch(receiver: address, ids: DynArray[uint256, BATCH_SIZE], amounts: Dy
     assert len(ids) == len(amounts), "ERC1155: ids and amounts length mismatch"
     operator: address = msg.sender
 
-    for i in range(BATCH_SIZE):
+    for i: uint256 in range(BATCH_SIZE):
         if i >= len(ids):
             break
         self.balanceOf[receiver][ids[i]] += amounts[i]
@@ -277,7 +277,7 @@ def burnBatch(ids: DynArray[uint256, BATCH_SIZE], amounts: DynArray[uint256, BAT
     assert len(ids) == len(amounts), "ERC1155: ids and amounts length mismatch"
     operator: address = msg.sender 
 
-    for i in range(BATCH_SIZE):
+    for i: uint256 in range(BATCH_SIZE):
         if i >= len(ids):
             break
         self.balanceOf[msg.sender][ids[i]] -= amounts[i]
@@ -333,7 +333,7 @@ def safeBatchTransferFrom(sender: address, receiver: address, ids: DynArray[uint
     assert sender == msg.sender or self.isApprovedForAll[sender][msg.sender], "Caller is neither owner nor approved operator for this ID"
     assert len(ids) == len(amounts), "ERC1155: ids and amounts length mismatch"
     operator: address = msg.sender
-    for i in range(BATCH_SIZE):
+    for i: uint256 in range(BATCH_SIZE):
         if i >= len(ids):
             break
         id: uint256 = ids[i]

examples/voting/ballot.vy

@@ -54,7 +54,7 @@ def directlyVoted(addr: address) -> bool:
 def __init__(_proposalNames: bytes32[2]):
     self.chairperson = msg.sender
     self.voterCount = 0
-    for i in range(2):
+    for i: int128 in range(2):
         self.proposals[i] = Proposal({
             name: _proposalNames[i],
             voteCount: 0
@@ -82,7 +82,7 @@ def _forwardWeight(delegate_with_weight_to_forward: address):
     assert self.voters[delegate_with_weight_to_forward].weight > 0
 
     target: address = self.voters[delegate_with_weight_to_forward].delegate
-    for i in range(4):
+    for i: int128 in range(4):
         if self._delegated(target):
             target = self.voters[target].delegate
             # The following effectively detects cycles of length <= 5,
@@ -157,7 +157,7 @@ def vote(proposal: int128):
 def _winningProposal() -> int128:
     winning_vote_count: int128 = 0
     winning_proposal: int128 = 0
-    for i in range(2):
+    for i: int128 in range(2):
         if self.proposals[i].voteCount > winning_vote_count:
             winning_vote_count = self.proposals[i].voteCount
             winning_proposal = i

examples/wallet/wallet.vy

@@ -14,7 +14,7 @@ seq: public(int128)
 
 @external
 def __init__(_owners: address[5], _threshold: int128):
-    for i in range(5):
+    for i: uint256 in range(5):
         if _owners[i] != empty(address):
             self.owners[i] = _owners[i]
     self.threshold = _threshold
@@ -47,7 +47,7 @@ def approve(_seq: int128, to: address, _value: uint256, data: Bytes[4096], sigda
     assert self.seq == _seq
     # # Iterates through all the owners and verifies that there signatures,
     # # given as the sigdata argument are correct
-    for i in range(5):
+    for i: uint256 in range(5):
         if sigdata[i][0] != 0:
             # If an invalid signature is given for an owner then the contract throws
             assert ecrecover(h2, sigdata[i][0], sigdata[i][1], sigdata[i][2]) == self.owners[i]

tests/functional/builtins/codegen/test_empty.py

@@ -423,7 +423,7 @@ def test_empty(xs: int128[111], ys: Bytes[1024], zs: Bytes[31]) -> bool: view
 @internal
 def write_junk_to_memory():
     xs: int128[1024] = empty(int128[1024])
-    for i in range(1024):
+    for i: uint256 in range(1024):
         xs[i] = -(i + 1)
 @internal
 def priv(xs: int128[111], ys: Bytes[1024], zs: Bytes[31]) -> bool:
@@ -469,7 +469,7 @@ def test_return_empty(get_contract_with_gas_estimation):
 @internal
 def write_junk_to_memory():
     xs: int128[1024] = empty(int128[1024])
-    for i in range(1024):
+    for i: uint256 in range(1024):
         xs[i] = -(i + 1)
 
 @external

tests/functional/builtins/codegen/test_mulmod.py

@@ -20,7 +20,7 @@ def test_uint256_mulmod_complex(get_contract_with_gas_estimation):
 @external
 def exponential(base: uint256, exponent: uint256, modulus: uint256) -> uint256:
     o: uint256 = 1
-    for i in range(256):
+    for i: uint256 in range(256):
         o = uint256_mulmod(o, o, modulus)
         if exponent & shift(1, 255 - i) != 0:
             o = uint256_mulmod(o, base, modulus)

tests/functional/builtins/codegen/test_slice.py

@@ -17,7 +17,7 @@ def test_basic_slice(get_contract_with_gas_estimation):
 @external
 def slice_tower_test(inp1: Bytes[50]) -> Bytes[50]:
     inp: Bytes[50] = inp1
-    for i in range(1, 11):
+    for i: uint256 in range(1, 11):
         inp = slice(inp, 1, 30 - i * 2)
     return inp
     """

tests/functional/codegen/features/iteration/test_break.py

@@ -11,7 +11,7 @@ def test_break_test(get_contract_with_gas_estimation):
 def foo(n: decimal) -> int128:
     c: decimal = n * 1.0
     output: int128 = 0
-    for i in range(400):
+    for i: int128 in range(400):
         c = c / 1.2589
         if c < 1.0:
             output = i
@@ -35,12 +35,12 @@ def test_break_test_2(get_contract_with_gas_estimation):
 def foo(n: decimal) -> int128:
     c: decimal = n * 1.0
     output: int128 = 0
-    for i in range(40):
+    for i: int128 in range(40):
         if c < 10.0:
             output = i * 10
             break
         c = c / 10.0
-    for i in range(10):
+    for i: int128 in range(10):
         c = c / 1.2589
         if c < 1.0:
             output = output + i
@@ -63,12 +63,12 @@ def test_break_test_3(get_contract_with_gas_estimation):
 def foo(n: int128) -> int128:
     c: decimal = convert(n, decimal)
     output: int128 = 0
-    for i in range(40):
+    for i: int128 in range(40):
         if c < 10.0:
             output = i * 10
             break
         c /= 10.0
-    for i in range(10):
+    for i: int128 in range(10):
         c /= 1.2589
         if c < 1.0:
             output = output + i
@@ -108,7 +108,7 @@ def foo():
         """
 @external
 def foo():
-    for i in [1, 2, 3]:
+    for i: uint256 in [1, 2, 3]:
         b: uint256 = i
     if True:
         break

tests/functional/codegen/features/iteration/test_continue.py

@@ -7,7 +7,7 @@ def test_continue1(get_contract_with_gas_estimation):
     code = """
 @external
 def foo() -> bool:
-    for i in range(2):
+    for i: uint256 in range(2):
         continue
         return False
     return True
@@ -21,7 +21,7 @@ def test_continue2(get_contract_with_gas_estimation):
 @external
 def foo() -> int128:
     x: int128 = 0
-    for i in range(3):
+    for i: int128 in range(3):
         x += 1
         continue
         x -= 1
@@ -36,7 +36,7 @@ def test_continue3(get_contract_with_gas_estimation):
 @external
 def foo() -> int128:
     x: int128 = 0
-    for i in range(3):
+    for i: int128 in range(3):
         x += i
         continue
     return x
@@ -50,7 +50,7 @@ def test_continue4(get_contract_with_gas_estimation):
 @external
 def foo() -> int128:
     x: int128 = 0
-    for i in range(6):
+    for i: int128 in range(6):
         if i % 2 == 0:
             continue
         x += 1
@@ -83,7 +83,7 @@ def foo():
         """
 @external
 def foo():
-    for i in [1, 2, 3]:
+    for i: uint256 in [1, 2, 3]:
         b: uint256 = i
     if True:
         continue