Reports duplicate declarations of classes, modules, interfaces, constants, global variables, type aliases, and methods.

Duplicate declarations produce DuplicatedDeclarationError.
Duplicate method definitions produce DuplicatedMethodDefinitionError.
Duplicate interface method definitions produce DuplicatedInterfaceMethodDefinitionError.

A quick fix is available to navigate to the duplicate declaration.

Example:

# Duplicate interface declaration
interface _Example
end

# Duplicate interface declaration
interface _Example
end