DIAGNOSTICS.md

Diagnostics Reference

This document is the stable reference for diagnostic IDs, descriptions, and example scenarios. IDs and anchors are stable; message text is localized.

Errors

DIE000

• Description: Unable to resolve a dependency in the object graph.
• Problem: The generator cannot find a binding or auto-binding that satisfies a required injection.
• Fix: Add a binding for the missing abstraction or enable/allow auto-binding for the concrete type.
• See: injections-of-abstractions.
• Examples: A root depends on a service that has no binding.

DIE001

• Description: Binding cannot be built due to missing binding metadata.
• Problem: A binding is missing required information (type, source, or factory).
• Fix: Ensure the binding has a valid .Bind(...).To<...>() or .Bind(...).To(ctx => ...) chain.
• See: simplified-binding.
• Examples: Binding is incomplete or the setup call is malformed.

DIE002

• Description: Binding is invalid because the compiler reported errors.
• Problem: The compiler produced errors in code used by the binding.
• Fix: Fix compilation errors in the referenced type or factory code.
• See: simplified-binding.
• Examples: Binding references a type that failed to compile.

DIE003

• Description: Composition type name is invalid.
• Problem: The composition name is not a valid C# type name.
• Fix: Use a valid identifier or fully qualified type name (letters/digits/underscore).
• See: composition-roots.
• Examples: DI.Setup("Bad Name!").

DIE004

• Description: Root name is invalid.
• Problem: The root property/method name is not a valid identifier.
• Fix: Use a valid C# identifier without spaces or punctuation.
• See: composition-roots.
• Examples: Root<Service>("Bad Name!").

DIE005

• Description: Duplicate root names detected.
• Problem: Multiple roots produce the same generated member name.
• Fix: Rename one of the roots to a unique name.
• See: composition-roots.
• Examples: Two roots with the same name.

DIE006

• Description: Argument name is invalid.
• Problem: Argument name is not a valid C# identifier.
• Fix: Use a valid identifier, for example argName or timeoutSeconds.
• See: composition-arguments.
• Examples: Arg<int>("bad name").

DIE007

• Description: Composition argument type is based on a generic marker.
• Problem: Composition arguments cannot use TT or marker-based types.
• Fix: Replace marker types with concrete types or proper generic parameters.
• See: composition-arguments.
• Examples: Arg<TT>("arg").

DIE008

• Description: Accumulator type is based on a generic marker.
• Problem: Accumulators cannot be defined with marker-based types.
• Fix: Use a concrete accumulator type or a valid generic type.
• See: accumulators.
• Examples: Accumulator<TT>().

DIE009

• Description: Accumulator cannot accumulate a generic marker.
• Problem: The accumulated element type is marker-based.
• Fix: Use concrete types or valid generic arguments for accumulated values.
• See: accumulators.
• Examples: Accumulator value uses TT.

DIE010

• Description: Special type cannot be a generic marker.
• Problem: SpecialType<T> does not accept marker-based types.
• Fix: Use concrete or supported special types.
• See: simplified-binding.
• Examples: SpecialType<IComparer<TT>>().

DIE011

• Description: Implementation does not implement the contract.
• Problem: The bound implementation does not satisfy the abstraction.
• Fix: Bind the correct implementation or change the contract to match.
• See: injections-of-abstractions.
• Examples: Bind<IService>().To<Service>() where Service does not implement IService.

DIE012

• Description: Attribute argument position is invalid.
• Problem: The attribute argument index does not exist.
• Fix: Use a valid argument index or adjust the attribute definition.
• See: custom-attributes.
• Examples: Attribute argument index is out of range.

DIE013

• Description: Attribute member cannot be processed.
• Problem: The attribute usage is ambiguous or conflicting.
• Fix: Use a single, unambiguous attribute or remove duplicates.
• See: custom-attributes.
• Examples: Multiple attributes cause ambiguity.

DIE014

• Description: Root type is invalid.
• Problem: Root declaration does not provide a valid type argument.
• Fix: Use Root<T> with a valid type.
• See: roots.
• Examples: Root() without a type argument.

DIE015

• Description: Roots type is invalid.
• Problem: The roots API requires a non-object type.
• Fix: Use a specific service/abstraction type.
• See: roots.
• Examples: Roots<object>().

DIE016

• Description: No type matched the wildcard filter.
• Problem: The wildcard filter excluded all candidate types.
• Fix: Adjust the filter or remove it to include matching types.
• See: roots-with-filter.
• Examples: Roots<IService>(filter: "NoMatch*").

DIE017

• Description: Builders type is invalid.
• Problem: The builders API requires a non-object type.
• Fix: Use a specific type for builders.
• See: builders.
• Examples: Builders<object>().

DIE018

• Description: Builder type is invalid.
• Problem: Builder declaration does not provide a valid type argument.
• Fix: Use Builder<T> with a valid type.
• See: builder.
• Examples: Builder() without a type argument.

DIE019

• Description: Too many type parameters provided.
• Problem: The API call uses more generic arguments than supported.
• Fix: Remove extra type arguments or use the correct overload.
• See: generics.
• Examples: Invalid generic API usage.

DIE020

• Description: Async factories are not supported.
• Problem: async lambdas are not supported in factory bindings.
• Fix: Use a synchronous factory or wrap async logic outside the composition.
• See: factory.
• Examples: .To(async ctx => ...).

DIE021

• Description: Unsupported syntax in DI API.
• Problem: The generator encountered an expression it cannot process.
• Fix: Use supported API patterns (constants, simple expressions, or factories).
• See: factory.
• Examples: Unsupported expressions passed into Bind/To/Root.

DIE022

• Description: Value must be of a specific type.
• Problem: A constant of the expected type is required.
• Fix: Provide a constant literal or use a supported API call.
• See: tags.
• Examples: Tag or hint expects a constant value.

DIE023

• Description: Identifier is invalid.
• Problem: A name used in setup is not a valid identifier.
• Fix: Use a valid identifier (letters/digits/underscore; no spaces).
• See: composition-roots.
• Examples: Root or builder name is not a valid C# identifier.

DIE024

• Description: Context is used directly where it is not allowed.
• Problem: ctx is used as a value rather than calling its methods.
• Fix: Replace direct usage with ctx.Inject(...) or ctx.Override(...).
• See: factory.
• Examples: ctx used as a value instead of ctx.Inject(...).

DIE025

• Description: Initializers count does not match.
• Problem: Factory initializers do not align with generated markers.
• Fix: Ensure the factory uses only supported initializer patterns.
• See: factory.
• Examples: Factory code does not match initializer markers.

DIE026

• Description: Lifetime does not support cyclic dependencies.
• Problem: The dependency graph contains cycles incompatible with the lifetime.
• Fix: Break the cycle or change lifetimes to compatible ones.
• See: scope.
• Examples: Singleton depending on Scoped with cycles.

DIE027

• Description: Composition is too large to build.
• Problem: Graph exploration exceeded the maximum iteration limit.
• Fix: Reduce graph size or adjust limits if supported.
• See: composition-roots.
• Examples: Graph iteration limit exceeded.

DIE028

• Description: Cannot construct an abstract type.
• Problem: The binding points to an abstract class or interface.
• Fix: Bind to a concrete implementation type.
• See: auto-bindings.
• Examples: Binding to an abstract class.

DIE029

• Description: No accessible constructor found.
• Problem: No public/internal constructors are available.
• Fix: Add an accessible constructor or use a factory binding.
• See: auto-bindings.
• Examples: Only private constructors are available.

DIE030

• Description: Dependency graph cannot be built.
• Problem: The graph cannot converge to a resolved state.
• Fix: Check for missing bindings or conflicting lifetimes.
• See: resolve-methods.
• Examples: Variational graph resolution failed.

DIE031

• Description: Maximum number of iterations reached.
• Problem: Graph building exceeded configured iteration limit.
• Fix: Simplify the graph or increase the limit.
• See: composition-roots.
• Examples: Graph build exceeded max iterations.

DIE032

• Description: No accessible constructor found for Tag.On.
• Problem: No constructor matches the Tag.On criteria.
• Fix: Update the type or the Tag.On arguments to match a constructor.
• See: tag-on-a-constructor-argument.
• Examples: Tag.OnConstructorArg<T>(...) with no matching constructor.

DIE033

• Description: No accessible method found for Tag.On.
• Problem: No method matches the Tag.On criteria.
• Fix: Update the type or the Tag.On arguments to match a method.
• See: tag-on-a-method-argument.
• Examples: Tag.OnMethodArg<T>(...) with no matching method.

DIE034

• Description: No accessible field or property found for Tag.On.
• Problem: No field/property matches the Tag.On criteria.
• Fix: Update the type or the Tag.On arguments to match a member.
• See: tag-on-a-member.
• Examples: Tag.OnMember<T>(...) with no matching member.

DIE035

• Description: Expression must be a valid API call.
• Problem: A non-constant or unsupported expression was provided.
• Fix: Use a constant, a supported API call, or rewrite the expression.
• See: tags.
• Examples: Passing a non-constant expression to Tag or Hint.

DIE036

• Description: Regular expression is invalid.
• Problem: The regex pattern cannot be parsed.
• Fix: Fix the regex syntax or escape special characters.
• See: oncannotresolve-regular-expression-hint.
• Examples: Invalid regex in a hint filter.

DIE037

• Description: Wildcard is invalid.
• Problem: The wildcard pattern is malformed.
• Fix: Use supported wildcard syntax.
• See: oncannotresolve-wildcard-hint.
• Examples: Invalid wildcard pattern in a hint filter.

DIE038

• Description: DI setup could not be found.
• Problem: DependsOn refers to a setup that does not exist.
• Fix: Add the missing setup or correct the name.
• See: dependent-compositions.
• Examples: DependsOn("MissingSetup").

DIE039

• Description: Cyclic dependency detected.
• Problem: A dependency cycle exists in the graph.
• Fix: Break the cycle or introduce a factory/Func to defer construction.
• See: injection-on-demand.
• Examples: A -> B -> A.

DIE040

• Description: Language version is not supported.
• Problem: The project uses a C# version below the required minimum.
• Fix: Increase the language version in project settings.
• See: composition-roots.
• Examples: Using C# language version below the minimum.

DIE041

• Description: Lifetime validation error.
• Problem: A root/lifetime combination is not allowed.
• Fix: Change lifetimes or root kind to a compatible configuration.
• See: static-root.
• Examples: Static root depends on Scoped/Singleton in unsupported way.

DIE042

• Description: Type cannot be inferred.
• Problem: The generator cannot determine the type from the expression.
• Fix: Specify the type explicitly (generic argument or cast).
• See: overrides.
• Examples: Override(...) without an inferable type.

DIE043

• Description: Unhandled generator error.
• Problem: An unexpected exception occurred in the generator.
• Fix: Reduce the scenario and report a bug with repro steps.
• See: check-for-a-root.

DIE044

• Description: DependsOn requires a setup context name when using a setup context kind (except Members).
• Problem: DependsOn was called with a setup context kind but without a context name.
• Fix: Provide a non-empty name value or use DependsOn(params string[] setupNames) when a context is not needed. SetupContextKind.Members allows omitting name.
• Examples: DependsOn(setupName, contextKind) without providing name parameter.

Warnings

DIW000

• Description: Binding has been overridden.
• Problem: A later binding replaces an earlier one for the same contract/tag.
• Fix: Remove the earlier binding or add tags to distinguish them.
• See: overriding-the-bcl-binding.
• Examples: Two bindings for the same contract/tag, the latter wins.

DIW001

• Description: No composition roots defined.
• Problem: The composition exposes no roots.
• Fix: Add at least one .Root(...) declaration.
• See: composition-roots.
• Examples: DI.Setup("Composition") without any .Root(...).

DIW002

• Description: Implementation does not implement the contract.
• Problem: The implementation does not satisfy the requested contract.
• Fix: Use a correct implementation or adjust the contract.
• See: injections-of-abstractions.
• Examples: Severity is Warning for not implemented contract.

DIW003

• Description: Binding is not used.
• Problem: The binding is never requested by any root.
• Fix: Remove unused bindings or reference them in a root.
• See: composition-roots.
• Examples: Binding has no consumers in the graph.

DIW004

• Description: Tag.On injection site is not used.
• Problem: The tag-on site is never matched by any injection.
• Fix: Update the Tag.On expression or add matching injections.
• See: tag-on-injection-site.
• Examples: Tag.On(...) not referenced by any injection.

DIW005

• Description: Resolve methods are incompatible with root arguments.
• Problem: Resolve cannot provide values for root arguments.
• Fix: Disable Resolve methods or remove RootArg usage.
• See: resolve-methods.
• Examples: Root uses RootArg but Resolve is enabled.

DIW006

• Description: Resolve methods are incompatible with type arguments.
• Problem: Resolve cannot supply generic type arguments.
• Fix: Use explicit roots or avoid Resolve for generic roots.
• See: resolve-methods.
• Examples: Generic roots with Resolve methods.

DIW007

• Description: DependsOn uses an instance member.
• Problem: A binding in a dependent setup references an instance member that will not exist in the dependent composition.
• Fix: Use .DependsOn(setupName, contextArgName) to pass an explicit setup context, or move the value to Arg/RootArg or a separate context object.
• See: dependent-compositions.
• Examples: Binding in a dependent setup uses instance field/property.

Info

DII000

• Description: Generation was interrupted.
• Problem: Generation aborted early due to a handled exception.
• Fix: Inspect preceding errors for the root cause.
• See: check-for-a-root.
• Examples: Generation aborted due to a handled exception.

DII001

• Description: Implementation does not implement the contract.
• Problem: The implementation does not satisfy the requested contract.
• Fix: Use a correct implementation or adjust the contract.
• See: injections-of-abstractions.
• Examples: Severity is Info for not implemented contract.