DFX4xxx --- Values, types and expressions

The block between the generated markers is written by .skill/gen-diagnostics.ps1. Everything below a marker is written by hand and survives a regeneration.

DFX4001

Severity error

Message

Input '%s' expects %s, but a number was written.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:631, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:641, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:656, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:743

Cause. A bare number was written where the input wants a vector, colour or other structured type.

Fix. Write all the components: (0, 0, -980).

DFX4002

Severity error

Message

Expression for '%s': a vector literal must have 2 to 4 components.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:132, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:362, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:515, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:625, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:664

Cause. Niagara vector types are 2, 3 or 4 components.

Fix. Check the component count.

DFX4003

Severity error

Message

Input '%s' is an integer, but %s was written. Narrowing is not implicit -- write int(%s) if truncation is intended.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:612

Cause. L7: float -> int is never implicit. A silently truncated spawn count is among the hardest effect bugs to find.

Fix. Write int(...) if truncation is what you meant, or make the source an int.

DFX4004

Severity error

Message

Input '%s' has no resolvable Niagara type.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:550, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:691

Cause. The input's type could not be resolved from the module schema.

Fix. Usually the input is hidden behind a static switch that has not been written yet -- write the switch first; source order is write order.

DFX4005

Severity error

Message

Property '%s': component %d is not a number.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1382, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1705, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:376, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:403, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:678, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:791

Cause. A vector or box() component is not a number.

Fix. Components are literals; a parameter reference cannot appear inside one.

DFX4006

Severity error

Message

Input '%s' is a %s, which has no entry named '%s'. Valid entries: %s

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:765

Cause. The enum has no entry by that name. Niagara's user-defined enums store NewEnumerator0 internally and keep the real name in display text, so the names here are not guessable from the asset -- they are read live.

Fix. Use one of the entries listed. Spaces and hyphens are normalised away, so Direct Set is written DirectSet.

DFX4007

Severity error

Message

Input '%s' expects %s. '%s' is neither a literal of that type nor a parameter reference -- parameter references start with a namespace such as User., Particles., Emitter., System. or Engine.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:774

Cause. The value is neither a literal of the expected type nor a namespace-qualified parameter.

Fix. Qualify the parameter (User.Speed, Particles.Velocity), or write a literal.

DFX4010

Severity error

Message

Input '%s' is set more than once on dynamic input '%s'.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1292, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1695

Cause. The same input was given twice on one dynamic input call.

Fix. Delete one.

DFX4020

Severity error

Message

Parameter '%s': 'Object' needs an inner type, e.g. Object<Texture>.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:394, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:439

Cause. DI names no class on its own.

Fix. Write the inner type: DI<SkeletalMesh>.

DFX4021

Severity error

Message

Parameter '%s': no UObject class named '%s'. Object<> takes a class name such as Object<Texture> or Object<StaticMesh>.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:427, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:473

Cause. The declared type is not one DreamFX knows.

Fix. Use one of the types listed in the message.

DFX4022

Severity error

Message

Cannot infer the type of '%s' from its value. A first assignment to a new attribute must use a literal, so its type is unambiguous.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:522

Cause. L2 types a new attribute from its first value, and this value carries no type -- an hlsl block, a dynamic input and an inline expression all have none of their own.

Fix. Write the type: Color Particles.Moon.Tint = hlsl { ... };

DFX4023

Severity error

Message

Property '%s': box() takes 6 numbers -- minX, minY, minZ, maxX, maxY, maxZ.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:619, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:631

Cause. box() is minX, minY, minZ, maxX, maxY, maxZ.

Fix. Write six numbers.

DFX4024

Severity error

Message

Cannot type '%s = %s': the type of '%s' is not known here. Declare it in Properties, or assign a literal first so the type is explicit.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:987

Cause. The right-hand side references a parameter whose type is not known at this point.

Fix. Declare it in Properties, or assign it a literal earlier in the same stack -- L2's first write is what declares an attribute.

DFX4025

Severity error

Message

'%s' is not a valid assignment target. Parameter names are namespace-qualified, e.g. Particles.MyValue or Emitter.MyCounter.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1373, Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:2298

Cause. An unqualified assignment target has no namespace to live in, and guessing one would put the value somewhere never named.

Fix. Qualify it: Particles.MyValue, Emitter.MyValue, System.MyValue.

DFX4026

Severity error

Message

'Bind %s -> %s': the target must be a qualified parameter -- either a namespace such as Particles.SpriteSize, or an emitter's own alias such as MyEmitter.Velocity.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1761

Cause. A renderer binding target is a parameter, not a bare name.

Fix. Write Bind Color -> Particles.Color;

DFX4027

Severity error

Message

'%s' is %s, but '%s' is %s. Linking binds a parameter directly -- there is no conversion. Declare '%s' as %s, or drive the input another way.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:1034

Cause. L7 across a link. A linked value binds the parameter directly -- there is no conversion step to truncate or widen in -- so the two types have to match exactly.

Fix. Declare the source parameter with the target's type. This is the one L7 case that cannot be fixed with an explicit cast, because there is nowhere to put one.

DFX4028

Severity error

Message

Default for '%s' needs a declared type. A default has no module signature to infer one from, so write it: `float %s = …`.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:2306

Cause. A Defaults entry was written without a type. Elsewhere the type can come from the value or from the module signature the input belongs to; a default belongs to no module and its value may be an hlsl block or a link, so there is nothing to infer from.

Fix. Write the type: float Particles.MySize = 1.0;.

DFX4029

Severity error

Message

Default for '%s' must be a literal, an enum or another parameter. A dynamic input computes a value per particle, which a default cannot do.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXGenerator.cpp:2352

Cause. A Defaults entry was given a dynamic input. A default is one value stored on the parameter, and a dynamic input is a graph that runs per particle -- there is nowhere to run it.

Fix. Use a literal, an enum, or a link to another parameter. If the value really has to be computed, write it as an assignment in ParticleSpawn instead, which runs.

DFX4030

Severity error

Message

The hlsl block for '%s' must be a single expression: no statements, no local variables, no return. Move multi-statement logic into a .dfm DynamicInput and call it here.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:367

Cause. A stack input's hlsl block lowers to a node with one typed output pin and no body, so it cannot hold statements.

Fix. Fold it into one expression, or move the logic into a .dfm Module, whose body is emitted verbatim. This is the gap .dfm generation exists to close.

DFX4031

Severity error

Message

'%s' is not an allowed inline function. Allowed: %s. Anything else belongs in a .dfm dynamic input or an hlsl { } block.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:171

Cause. L6's whitelist. Widening it is the slide into re-implementing a 13k-line expression backend, so it is deliberately short.

Fix. Use one of the listed functions, a .dfm dynamic input, or an hlsl { } block -- inside which any HLSL is allowed.

DFX4032

Severity error

Message

'%s' in the expression for '%s' is not a parameter. Only namespace-qualified parameters (User.X, Particles.X, Engine.X, ...) can be read from an expression.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:113

Cause. Inline expressions see parameters, not locals. A bare name has nothing to bind to.

Fix. Qualify it, or move the expression into an hlsl { } block where locals exist.

DFX4033

Severity error

Message

Builtin '%s' takes positional arguments, not named ones.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:179

Cause. An L6 builtin is positional. Named arguments read as a dynamic input call and would silently resolve to something else.

Fix. Write saturate(x), not saturate(Value = x).

DFX4034

Severity error

Message

Builtin '%s' takes %d argument(s), but %d were written.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:187

Cause. Arity is the only thing separating lerp(a, b) from lerp(a, b, t).

Fix. Check the argument count.

DFX4035

Severity error

Message

Expression for '%s' contains a value that has no HLSL form.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:232

Cause. Part of the expression has no HLSL form -- a curve literal or a data interface inside arithmetic, for instance.

Fix. Move that part to its own input.

DFX4036

Severity error

Message

The hlsl block for '%s' is empty.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:357

Cause. An empty hlsl block lowers to an expression with no text in it.

Fix. Write the expression, or delete the block.

DFX4037

Severity error

Message

'%s' is %s; a curve { } literal only fits a curve data interface input.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:383

Cause. A curve { } literal fills a curve data interface, and this input is not one.

Fix. Feed the curve to the input that takes it -- usually a dynamic input such as FloatFromCurve(FloatCurve = curve { ... }).

DFX4038

Severity error

Message

The curve for '%s' has no keys.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:391

Cause. An empty curve evaluates to nothing, which reads at runtime as a value stuck at zero.

Fix. Add keys.

DFX4039

Severity error

Message

Unknown curve interpolation '%s'. Expected Auto, Cubic, Linear or Constant.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:405

Cause. Curve tangents are data (plan 3.5); an unrecognised mode would fall back to Auto and drop a hand-tuned shape without saying so.

Fix. Use Auto, Cubic, Linear or Constant.

DFX4040

Severity error

Message

Parameter '%s': no asset at '%s'.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:716

Cause. An Object<T> parameter was given an asset path and nothing is at that path. Usually the asset moved or was renamed after the source was written, or the path is a content-browser display name rather than an object path.

Fix. Copy the path from the asset's right-click Copy Reference and paste it whole: Object<Texture> _Tex = "/Game/FX/T_Spark.T_Spark";. The part after the dot is the object name inside the package and is not optional.

DFX4041

Severity error

Message

Parameter '%s': '%s' is a %s, which is not a %s.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:725

Cause. The asset at that path exists but is not the class the parameter declares. Object<Texture> = ".../M_Fire" names a material, and Niagara would refuse the binding at runtime rather than at build time.

Fix. Either point at an asset of the declared class, or widen the declaration to the class you actually mean --- Object<Texture>, Object<StaticMesh>, Object<MaterialInterface> and so on match what the module's input expects.

DFX4042

Severity error

Message

Unknown curve tangent mode '%s'. Expected Auto, User, Break or None.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXExpressions.cpp:415

Cause. A curve key's Tangent= attribute named something that is not one of Unreal's four tangent modes. Refused rather than defaulted for the same reason as DFX4039: falling back to Auto would silently discard the tangents written beside it, and a curve whose corners have been rounded off is a different curve.

Fix. Use Auto, User, Break or None --- or leave Tangent out entirely, in which case a key with a tangent means User and a key without means Auto, which is what every source written before the attribute existed meant.

DFX4043

Severity error

Message

Input '%s' is an instance-backed %s and cannot have a literal or asset-path default. Omit the default and supply an instance through a system parameter or stack input.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:537, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:733

Cause. A data interface or other instance-backed object input has a literal or asset-path default, or an object reference resolves to a non-asset instance.

Fix. Omit instance-backed defaults and provide the instance through a system parameter or stack input; use a compatible asset reference only for an asset-backed object input.

DFX4044

Severity error

Message

An int(...) default requires one numeric literal. Runtime casts belong in a stack expression.

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:570, Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:577

Cause. An int(...) literal conversion is non-finite or outside the signed 32-bit range, or a stored default uses an argument other than one numeric literal.

Fix. Use a finite numeric literal whose truncated value fits int32; put conversions of runtime parameters in stack expressions instead of literal defaults.

DFX4091

Severity error

Message

Input '%s': dynamic inputs, hlsl blocks, curves and inline expressions are not available yet (planned for Phase 3).

Raised by Source/DreamFXEditor/Private/Generation/DreamFXValueLowering.cpp:785

Cause. A Phase 2 build met a Phase 3 value mode. Historical -- it should not appear on a current build.

Fix. Rebuild the plugin. If it persists, the source is being compiled by an old binary.