diff --git a/compiler/src/prog8/compiler/astprocessing/AstChecker.kt b/compiler/src/prog8/compiler/astprocessing/AstChecker.kt
index 4b636f521..aa39a8ab1 100644
--- a/compiler/src/prog8/compiler/astprocessing/AstChecker.kt
+++ b/compiler/src/prog8/compiler/astprocessing/AstChecker.kt
@@ -519,7 +519,7 @@ internal class AstChecker(private val program: Program,
         }
 
         // FLOATS enabled?
-        if(!compilerOptions.floats && decl.datatype in setOf(DataType.FLOAT, DataType.ARRAY_F) && decl.type!= VarDeclType.MEMORY)
+        if(!compilerOptions.floats && decl.datatype.oneOf(DataType.FLOAT, DataType.ARRAY_F) && decl.type!= VarDeclType.MEMORY)
             err("floating point used, but that is not enabled via options")
 
         if(decl.datatype == DataType.FLOAT && (decl.zeropage==ZeropageWish.REQUIRE_ZEROPAGE || decl.zeropage==ZeropageWish.PREFER_ZEROPAGE))
diff --git a/compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt b/compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt
index 83c19af1e..f45f7dec7 100644
--- a/compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt
+++ b/compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt
@@ -182,7 +182,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
 
     override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
         // warn about any implicit type casts to Float, because that may not be intended
-        if(typecast.implicit && typecast.type in setOf(DataType.FLOAT, DataType.ARRAY_F)) {
+        if(typecast.implicit && typecast.type.oneOf(DataType.FLOAT, DataType.ARRAY_F)) {
             errors.warn("integer implicitly converted to float. Suggestion: use float literals, add an explicit cast, or revert to integer arithmetic", typecast.position)
         }
         return noModifications
diff --git a/compilerAst/src/prog8/ast/base/Base.kt b/compilerAst/src/prog8/ast/base/Base.kt
index a446fc264..a0c93931c 100644
--- a/compilerAst/src/prog8/ast/base/Base.kt
+++ b/compilerAst/src/prog8/ast/base/Base.kt
@@ -24,16 +24,17 @@ enum class DataType {
      */
     infix fun isAssignableTo(targetType: DataType) =
             when(this) {
-                UBYTE -> targetType in setOf(UBYTE, WORD, UWORD, FLOAT)
-                BYTE -> targetType in setOf(BYTE, WORD, FLOAT)
-                UWORD -> targetType in setOf(UWORD, FLOAT)
-                WORD -> targetType in setOf(WORD, FLOAT)
+                UBYTE -> targetType.oneOf(UBYTE, WORD, UWORD, FLOAT)
+                BYTE -> targetType.oneOf(BYTE, WORD, FLOAT)
+                UWORD -> targetType.oneOf(UWORD, FLOAT)
+                WORD -> targetType.oneOf(WORD, FLOAT)
                 FLOAT -> targetType == FLOAT
                 STR -> targetType == STR
                 in ArrayDatatypes -> targetType == this
                 else -> false
             }
 
+    fun oneOf(vararg types: DataType) = this in types
     infix fun isAssignableTo(targetTypes: Set<DataType>) = targetTypes.any { this isAssignableTo it }
     infix fun isNotAssignableTo(targetType: DataType) = !this.isAssignableTo(targetType)
     infix fun isNotAssignableTo(targetTypes: Set<DataType>) = !this.isAssignableTo(targetTypes)
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 2c089be3b..bbd42c7d3 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -3,8 +3,9 @@ TODO
 
 For next compiler release
 ^^^^^^^^^^^^^^^^^^^^^^^^^
-replace checks against multiple types with .oneOf(...)
+replace checks of InferredType against multiple types with .oneOf(...)
 replace certain uses of inferredType.getOr(UNKNOWN) by i.getOrElse({ errorhandler })
+replace registerOrPair in setOf(..) by .oneOf(..) varargs function
 
 
 Blocked by Commander-x16 v39 release