TPZ5022: Malformed or unknown type

Compiler phase: check.

Compiler explanation: A type annotation, alias, or protocol bound names a type/protocol form that is not valid here.

Message templates. The marker ⟨value⟩ stands for text computed for the reported program.

• export function main must be non-generic and have signature ⟨value⟩; found ⟨value⟩ Source
• cannot infer a return type for ⟨value⟩: it returns a destructured generic value with no nameable type — annotate the return type Source
• ⟨value⟩ is (mutually) recursive: declare its return type (§7) Source
• cannot derive ⟨value⟩ for generic nominal ⟨value⟩ yet; conditional generic conformance is not defined Source
• integer literal ⟨value⟩ is out of range Source
• record literal declares field ⟨value⟩ twice Source
• ⟨value⟩ takes ⟨value⟩ type argument⟨value⟩, found ⟨value⟩ Source
• integer literal type ⟨value⟩ is out of range Source
• record type declares field ⟨value⟩ twice Source
• type parameter ⟨value⟩ takes no type arguments Source
• primitive type ⟨value⟩ takes no type arguments Source
• ⟨value⟩ takes no type arguments Source
• ⟨value⟩ name ⟨value⟩ collides with ⟨value⟩; choose another name Source
• enum variant ⟨value⟩ collides with a reserved prelude constructor; choose another variant name Source
• enum variant ⟨value⟩ has a payload ⟨value⟩ that is a union containing an enum — enum-in-union payloads are not supported Source
• protocol method ⟨value⟩.⟨value⟩ cannot be generic Source
• protocol method ⟨value⟩.⟨value⟩ must take the conforming value as its first parameter Source
• protocol method ⟨value⟩.⟨value⟩ requires an explicit return type (use -> () for unit) Source
• protocol method ⟨value⟩.⟨value⟩ cannot be variadic Source
• protocol method ⟨value⟩.⟨value⟩ cannot declare parameter defaults Source
• protocol method ⟨value⟩.⟨value⟩ must use Self or the protocol's type parameter as its first parameter type Source
• ⟨value⟩ is already a type and cannot also be a protocol Source
• protocol ⟨value⟩ takes at most one conforming-type parameter; found ⟨value⟩ Source
• protocol ⟨value⟩ has no method ⟨value⟩ Source
• protocol implementation method ⟨value⟩.⟨value⟩ is module-local and cannot be exported Source
• protocol implementation method ⟨value⟩.⟨value⟩ cannot be generic Source
• protocol implementation method ⟨value⟩.⟨value⟩ requires an explicit return type (use -> () for unit) Source
• protocol implementation method ⟨value⟩.⟨value⟩ cannot be variadic Source
• protocol implementation method ⟨value⟩.⟨value⟩ cannot declare parameter defaults Source
• protocol implementation method ⟨value⟩.⟨value⟩ must match the declared signature exactly; expected ⟨value⟩, found ⟨value⟩ Source
• unknown protocol ⟨value⟩ in impl ⟨value⟩<⟨value⟩> Source
• JSON conformance is derive-only; use derives JSON Source
• cannot implement protocol ⟨value⟩ for generic nominal ⟨value⟩ yet; generic conformance binders are not defined Source
• impl ⟨value⟩<⟨value⟩> is missing method ⟨value⟩ Source
• method ⟨value⟩ on ⟨value⟩ must take self as its first parameter Source
• method ⟨value⟩ on ⟨value⟩ must take bare self as its first parameter (no type annotation, default, or variadic marker) Source
• generic methods are not supported yet (method ⟨value⟩) Source
• method name ⟨value⟩ on ⟨value⟩ collides with a builtin member; choose another name Source
• method ⟨value⟩ on ⟨value⟩ collides with a field of the same name; rename the method (a field shadows a method) Source
• an impl block cannot be exported; mark individual methods with export Source
• cannot define methods on ⟨value⟩ (⟨value⟩); impl is only allowed on an own-module record, enum, or newtype Source
• cannot define receiver methods on generic nominal ⟨value⟩ yet; generic impl binders are not defined Source
• ⟨value⟩ declarations are module-top-level only Source

Observed for the candidate in Topaz 5.21.3. Execution

• error[TPZ5022]: protocol implementation method Show.show must match the declared signature exactly; expected (Item) -> string, found (int) -> string

A protocol implementation signature differs from its protocol, or a type cannot be determined under the applicable annotation rule.

Compare the declaration with the required type or protocol signature. Match the declared parameter and result types and remove unsupported type-related forms.