Analyzer diagnostics

Mapperly emits several diagnostics:

Rule ID	Severity	Description
RMG001	Error	A mapping method has an unsupported signature.
RMG002	Error	No accessible parameterless constructor found.
RMG003	Warning	No overlapping enum members found.
RMG004	Warning	Ignored target member not found.
RMG005	Error	Mapping target member not found.
RMG006	Error	Mapping source member not found.
RMG007	Error	Could not map member.
RMG008	Error	Could not create mapping.
RMG009	Info	Cannot map to read only member.
RMG010	Info	Cannot map from write only member.
RMG011	Info	Cannot map to write only member path.
RMG012	Info	Source member was not found for target member
RMG013	Error	No accessible constructor with mappable arguments found
RMG014	Warning	Cannot map to the configured constructor to be used by Mapperly
RMG015	Info	Cannot map to init only member path
RMG016	Error	Init only member cannot handle target paths
RMG017	Warning	An init only member can have one configuration at max
RMG018	Error	Partial static mapping method in an instance mapper
RMG020	Info	Source member is not mapped to any target member
RMG021	Warning	Ignored source member not found
RMG022	Error	Invalid object factory signature
RMG023	Error	Mapping source member for a required target member not found
RMG024	Error	The reference handler parameter is not of the correct type
RMG025	Error	To use reference handling it needs to be enabled on the mapper attribute
RMG026	Info	Cannot map from indexed member
RMG027	Warning	A constructor parameter can have one configuration at max
RMG028	Error	Constructor parameter cannot handle target paths
RMG029	Error	Queryable projection mappings do not support reference handling
RMG030	Error	Reference loop detected while mapping to an init only member
RMG031	Warning	Reference loop detected while mapping to a constructor member
RMG032	Warning	The enum mapping strategy ByName cannot be used in projection mappings
RMG033	Info	Object mapped to another object without deep clone
RMG034	Error	Derived source type is specified multiple times, a source type may only be specified once
RMG035	Error	Derived source type is not assignable to parameter type
RMG036	Error	Derived target type is not assignable to return type
RMG037	Info	An enum member could not be found on the source enum
RMG038	Info	An enum member could not be found on the target enum
RMG039	Error	Enum source value is specified multiple times, a source enum value may only be specified once
RMG040	Error	A target enum member value does not match the target enum type
RMG041	Error	A source enum member value does not match the source enum type
RMG042	Error	The type of the enum fallback value does not match the target enum type
RMG043	Warning	Enum fallback values are only supported for the ByName and ByValueCheckDefined strategies, but not for the ByValue strategy
RMG044	Warning	An ignored enum member can not be found on the source enum
RMG045	Warning	An ignored enum member can not be found on the target enum
RMG046	Error	The used C# language version is not supported by Mapperly, Mapperly requires at least C# 9.0
RMG047	Error	Cannot map to member path due to modifying a temporary value, see CS1612
RMG048	Error	Used mapper members cannot be nullable
RMG049	Warning	Source member is ignored and also explicitly mapped
RMG050	Warning	Target member is ignored and also explicitly mapped

info

Mapperly only emits updated source code on build. You won't see the updated mapper code or mapper diagnostics until you perform a build.

This is done for performance reasons, otherwise the IDE could become laggy.

Editorconfig

The severity of these diagnostics can be customized via an .editorconfig file:

.editorconfig

[*.cs]
dotnet_diagnostic.{RuleID}.severity = error
dotnet_diagnostic.RMG020.severity = error