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Version: v6

Text/name Title Picture

Applicable to ink! messages, ink! constructors and ink! events.

Specifies a name/identifier override that is used in place of the item's name/identifier for:

In general, name overrides should mainly be used to:

  • Implement contracts compliant with Ethereum/Solidity contract standards (i.e. ERCs) that require/use overloaded interfaces
  • Define interfaces (e.g. via trait definitions) for interacting with existing Solidity ABI encoded contracts with overloaded interfaces
  • As a more transparent alternative to custom selectors for the "name-changing while maintaining the same selector" use case for ink! ABI contracts
note

For native/ink! ABI, message and constructor selectors are computed from the item name/identifier alone, so multiple messages with the same name attribute override will have the same computed selector, which results in a compilation error about the overlapping selectors.

In general, more semantic interfaces with descriptive and unique item names/identifiers are encouraged for new contracts (especially contracts that support the ink! ABI i.e. "ink" or "all" ABI mode).

Examples​

#[ink(message, name = "myConstructor")]
fn my_constructor(&self) {}

#[ink(message, name = "myMessage")]
fn my_message(&self) {}

#[ink::event(name = "MyEvent")]
pub struct Event { ... }

This changes the resulting selectors of the ink! message and ink! constructor, and the signature topic for the ink! event, as well as their names in contract metadata.

note

For native/ink! ABI, the selector attribute has higher precedence than the name attribute. This means that the manually provided selector is used when an ink! message or ink! constructor is annotated with both the selector and name attributes e.g. in the example below, the selector for the ink! message is 0x1.

#[ink(message, name = "myMessage", selector = 0x1)]
fn my_message(&self) {}