[Bug]: IV4Router Struct Mismatch Causes Type Conversion Error in ExactOutputSingleParams

[cqlyj]

Describe the bug

Description

In the file IV4Router, imported via:

import {IV4Router} from "v4-periphery/src/interfaces/IV4Router.sol";

I noticed that the parameter structure differs from what is documented. I previously raised an issue regarding this discrepancy here.

After attempting to remove the following code snippet:

IV4Router.ExactOutputSingleParams({
    poolKey: poolKey,
    zeroForOne: true, // true if swapping token0 for token1: USDC => NFT
    amountOut: amountOut,
    amountInMaximum: maxAmountIn,
    // sqrtPriceLimitX96: 0, // No price limit
    hookData: hookData
});

I encountered a new error:

Invalid type for argument in function call.  
Invalid implicit conversion from struct PoolKey memory to struct PoolKey memory requested.  
solidity(9553)

What I’ve Tried

• Verified that my installed v4-core commit hash is b619b67, and the v4-periphery commit hash matches.
• However, if I do not import IV4Router and instead define my own minimal interface:

interface IV4Router {
    struct ExactOutputSingleParams {
        PoolKey poolKey;
        bool zeroForOne;
        uint128 amountOut;
        uint128 amountInMaximum;
        uint160 sqrtPriceLimitX96;
        bytes hookData;
    }
}

then everything compiles and works as expected.

Question

Why does using the imported IV4Router cause a type conversion error, but defining a local version of the interface resolves it? Could this be due to different struct definitions in v4-core vs. v4-periphery despite the same commit hash?

Would appreciate any insights—thanks!

Expected Behavior

When importing IV4Router from v4-periphery, the ExactOutputSingleParams struct should match the documented definition and work without type conversion errors.

• The struct should accept PoolKey without requiring any implicit conversions.
• Removing sqrtPriceLimitX96 should not cause an error.
• Using the official IV4Router interface should behave the same as a manually defined minimal version.

To Reproduce

1. Import IV4Router from v4-periphery and PoolKey from v4-core:

   import {IV4Router} from "v4-periphery/src/interfaces/IV4Router.sol";
   import {PoolKey} from "v4-core/src/types/PoolKey.sol";

2. Use the ExactOutputSingleParams struct in a function:

   IV4Router.ExactOutputSingleParams({
       poolKey: poolKey,
       zeroForOne: true, // true if swapping token0 for token1: USDC => NFT
       amountOut: amountOut,
       amountInMaximum: maxAmountIn,
       // sqrtPriceLimitX96: 0, // No price limit
       hookData: hookData
   });

3. Compile the contract and observe the error:

   Invalid type for argument in function call.
   Invalid implicit conversion from struct PoolKey memory to struct PoolKey memory requested.
   solidity(9553)
   

4. Instead, define a minimal interface manually:

   interface IV4Router {
       struct ExactOutputSingleParams {
           PoolKey poolKey;
           bool zeroForOne;
           uint128 amountOut;
           uint128 amountInMaximum;
           uint160 sqrtPriceLimitX96;
           bytes hookData;
       }
   }

5. Replace the imported IV4Router with the manually defined one, and compile again—this time, it works without errors.

Additional context

No response

[linear]

PROTO-750 [Bug]: IV4Router Struct Mismatch Causes Type Conversion Error in ExactOutputSingleParams

[saucepoint]

@cqlyj this is a repo configuration problem. If you want to use v4-periphery with a top-level v4-core install, you will need to remap v4-periphery's core dependency:

inside remappings.txt

lib/v4-periphery:@uniswap/v4-core/=lib/v4-core/

v4-periphery installs with its own copy of v4-core, so youre attempting to use PoolKey definitions from different files (lib/v4-core and lib/v4-periphery/lib/v4-core)

[cqlyj]

@cqlyj this is a repo configuration problem. If you want to use v4-periphery with a top-level v4-core install, you will need to remap v4-periphery's core dependency:

inside remappings.txt

lib/v4-periphery:@uniswap/v4-core/=lib/v4-core/

v4-periphery installs with its own copy of v4-core, so youre attempting to use PoolKey definitions from different files (lib/v4-core and lib/v4-periphery/lib/v4-core)

That fix this, Thanks! But that IRouterV4 issue is still there: Uniswap/docs#901