Function: _swap(address fromToken, address toToken, address pool, int128 i, int128 j, uint256 fromAmount, uint256 toAmountMin)

This swaps on Curve with the logic for an ERC-20 pool.

Inputs

• fromToken

  • Constraints: No constraints.

  • Impact: The token being swapped from.

• toToken

  • Constraints: No constraints.

  • Impact: The token being swapped to.

• pool

  • Constraints: No constraints.

  • Impact: The Curve pool being swapped with.

• i

  • Constraints: No constraints.

  • Impact: The index of the fromToken in the Curve pool.

• j

  • Constraints: No constraints.

  • Impact: The index of the toToken in the Curve pool.

• fromAmount

  • Constraints: No constraints.

  • Impact: The amount of fromToken to swap.

• toAmountMin

  • Constraints: No constraints.

  • Impact: The minimum amount of toToken to receive from the swap.

Branches and code coverage (including function calls)

Intended branches

• The swap on Curve succeeds with the given parameters.

  Test coverage

Negative behaviour

• The swap on Curve fails if output tokens are less than toAmountMin .

  Negative test

Function call analysis

• ERC20(fromToken).safeApprove(pool, fromAmount)

  • What is controllable? fromToken, pool, and fromAmount.

  • If return value controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.

• ERC20(toToken).balanceOf(address(this))

  • What is controllable? toToken.

  • If return value controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.

• ICurvePair(pool).exchange(i, j, fromAmount, toAmountMin)

  • What is controllable? pool, i, j, fromAmount, and toAmountMin.

  • If return value controllable, how is it used and how can it go wrong? N/A.

  • What happens if it reverts, reenters, or does other unusual control flow? If this reverts, the entire call fails --- no reentrancy issues.