FIR: add groups to diagnostics DSL

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/Diagnostic.kt

@@ -5,10 +5,7 @@
 
 package org.jetbrains.kotlin.fir.checkers.generator.diagnostics
 
-import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.diagnostics.Severity
-import org.jetbrains.kotlin.fir.FirSourceElement
-import kotlin.reflect.KClass
 import kotlin.reflect.KType
 
 data class Diagnostic(
@@ -18,6 +15,7 @@ data class Diagnostic(
     val psiType: KType,
     val parameters: List<DiagnosticParameter>,
     val positioningStrategy: PositioningStrategy,
+    val group: String?,
 )
 
 data class DiagnosticParameter(

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/DiagnosticListBuilder.kt

@@ -19,6 +19,19 @@ class DiagnosticListBuilder private constructor() {
     @PrivateForInline
     val diagnostics = mutableListOf<Diagnostic>()
 
+    @PrivateForInline
+    var currentGroupName: String? = null
+
+    @OptIn(PrivateForInline::class)
+    inline fun group(groupName: String, inner: () -> Unit) {
+        if (currentGroupName != null) {
+            error("Groups can not be nested ")
+        }
+        currentGroupName = groupName
+        inner()
+        currentGroupName = null
+    }
+
     @OptIn(PrivateForInline::class)
     inline fun <reified E : FirSourceElement, reified P : PsiElement> error(
         positioningStrategy: PositioningStrategy = PositioningStrategy.DEFAULT,
@@ -45,6 +58,7 @@ class DiagnosticListBuilder private constructor() {
             sourceElementType = typeOf<E>(),
             psiType = typeOf<P>(),
             positioningStrategy,
+            group = currentGroupName,
         ).apply(init).build()
         AlwaysReturningUnitPropertyDelegate
     }
@@ -68,7 +82,8 @@ class DiagnosticBuilder(
     private val name: String,
     private val sourceElementType: KType,
     private val psiType: KType,
-    private val positioningStrategy: PositioningStrategy
+    private val positioningStrategy: PositioningStrategy,
+    private val group: String?
 ) {
     @PrivateForInline
     val parameters = mutableListOf<DiagnosticParameter>()
@@ -92,5 +107,6 @@ class DiagnosticBuilder(
         psiType,
         parameters,
         positioningStrategy,
+        group
     )
 }

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/ErrorListDiagnosticListRenderer.kt

@@ -33,12 +33,24 @@ object ErrorListDiagnosticListRenderer : DiagnosticListRenderer() {
 
     private fun SmartPrinter.printErrorsObject(diagnosticList: DiagnosticList) {
         inBracketsWithIndent("object FirErrors") {
-            for (it in diagnosticList.diagnostics) {
+            val groups = diagnosticList.diagnostics.groupBy { it.group }
-                printDiagnostic(it)
+            for ((group, diagnostics) in groups) {
+                printDiagnosticGroup(group, diagnostics)
+                println()
             }
         }
     }
 
+    private fun SmartPrinter.printDiagnosticGroup(
+        group: String?,
+        diagnostics: List<Diagnostic>
+    ) {
+        println("// ${group ?: "NO GROUP"}")
+        for (it in diagnostics) {
+            printDiagnostic(it)
+        }
+    }
+
     private fun SmartPrinter.printDiagnostic(diagnostic: Diagnostic) {
         print("val ${diagnostic.name} by ${diagnostic.getFactoryFunction()}")
         printTypeArguments(diagnostic.getAllTypeArguments())

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -25,11 +25,12 @@ import org.jetbrains.kotlin.psi.*
 @Suppress("UNUSED_VARIABLE", "LocalVariableName")
 @OptIn(PrivateForInline::class)
 val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
-    // Miscellaneous
+    group("Miscellaneous") {
         val SYNTAX by error<FirSourceElement, PsiElement>()
         val OTHER_ERROR by error<FirSourceElement, PsiElement>()
+    }
 
-    // General syntax
+    group("General syntax") {
         val ILLEGAL_CONST_EXPRESSION by error<FirSourceElement, PsiElement>()
         val ILLEGAL_UNDERSCORE by error<FirSourceElement, PsiElement>()
         val EXPRESSION_REQUIRED by error<FirSourceElement, PsiElement>()
@@ -38,8 +39,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val VARIABLE_EXPECTED by error<FirSourceElement, PsiElement>()
         val RETURN_NOT_ALLOWED by error<FirSourceElement, PsiElement>()
         val DELEGATION_IN_INTERFACE by error<FirSourceElement, PsiElement>()
+    }
 
-    // Unresolved
+    group("Unresolved") {
         val HIDDEN by error<FirSourceElement, PsiElement> {
             parameter<AbstractFirBasedSymbol<*>>("hidden")
         }
@@ -52,16 +54,18 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val UNKNOWN_CALLABLE_KIND by error<FirSourceElement, PsiElement>()
         val MISSING_STDLIB_CLASS by error<FirSourceElement, PsiElement>()
         val NO_THIS by error<FirSourceElement, PsiElement>()
+    }
 
-    // Super
+    group("Super") {
         val SUPER_IS_NOT_AN_EXPRESSION by error<FirSourceElement, PsiElement>()
         val SUPER_NOT_AVAILABLE by error<FirSourceElement, PsiElement>()
         val ABSTRACT_SUPER_CALL by error<FirSourceElement, PsiElement>()
         val INSTANCE_ACCESS_BEFORE_SUPER_CALL by error<FirSourceElement, PsiElement>() {
             parameter<String>("target")
         }
+    }
 
-    // Supertypes
+    group("Supertypes") {
         val TYPE_PARAMETER_AS_SUPERTYPE by error<FirSourceElement, PsiElement>()
         val ENUM_AS_SUPERTYPE by error<FirSourceElement, PsiElement>()
         val RECURSION_IN_SUPERTYPES by error<FirSourceElement, PsiElement>()
@@ -75,8 +79,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val CLASS_IN_SUPERTYPE_FOR_ENUM by error<FirSourceElement, PsiElement>()
         val SEALED_SUPERTYPE by error<FirSourceElement, PsiElement>()
         val SEALED_SUPERTYPE_IN_LOCAL_CLASS by error<FirSourceElement, PsiElement>()
+    }
 
-    // Constructor problems
+    group(" Constructor problems") {
         val CONSTRUCTOR_IN_OBJECT by error<FirSourceElement, KtDeclaration>(PositioningStrategy.DECLARATION_SIGNATURE)
         val CONSTRUCTOR_IN_INTERFACE by error<FirSourceElement, KtDeclaration>(PositioningStrategy.DECLARATION_SIGNATURE)
         val NON_PRIVATE_CONSTRUCTOR_IN_ENUM by error<FirSourceElement, PsiElement>()
@@ -88,8 +93,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val PRIMARY_CONSTRUCTOR_REQUIRED_FOR_DATA_CLASS by warning<FirSourceElement, PsiElement>()
         val EXPLICIT_DELEGATION_CALL_REQUIRED by warning<FirSourceElement, PsiElement>(PositioningStrategy.SECONDARY_CONSTRUCTOR_DELEGATION_CALL)
         val SEALED_CLASS_CONSTRUCTOR_CALL by error<FirSourceElement, PsiElement>()
+    }
 
-    // Annotations
+    group("Annotations") {
         val ANNOTATION_ARGUMENT_KCLASS_LITERAL_OF_TYPE_PARAMETER_ERROR by error<FirSourceElement, KtExpression>()
         val ANNOTATION_ARGUMENT_MUST_BE_CONST by error<FirSourceElement, KtExpression>()
         val ANNOTATION_ARGUMENT_MUST_BE_ENUM_CONST by error<FirSourceElement, KtExpression>()
@@ -105,8 +111,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         }
         val NULLABLE_TYPE_OF_ANNOTATION_MEMBER by error<FirSourceElement, KtTypeReference>()
         val VAR_ANNOTATION_PARAMETER by error<FirSourceElement, KtParameter>(PositioningStrategy.VAL_OR_VAR_NODE)
+    }
 
-    // Exposed visibility group
+    group("Exposed visibility group") {
         val EXPOSED_TYPEALIAS_EXPANDED_TYPE by exposedVisibilityError<KtNamedDeclaration>(PositioningStrategy.DECLARATION_NAME)
         val EXPOSED_FUNCTION_RETURN_TYPE by exposedVisibilityError<KtNamedDeclaration>(PositioningStrategy.DECLARATION_NAME)
 
@@ -116,8 +123,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val EXPOSED_SUPER_INTERFACE by exposedVisibilityError<KtTypeReference>()
         val EXPOSED_SUPER_CLASS by exposedVisibilityError<KtTypeReference>()
         val EXPOSED_TYPE_PARAMETER_BOUND by exposedVisibilityError<KtTypeReference>()
+    }
 
-    // Modifiers
+    group("Modifiers") {
         val INAPPLICABLE_INFIX_MODIFIER by error<FirSourceElement, PsiElement> {
             parameter<String>("modifier") // TODO or it should be a message?
         }
@@ -137,8 +145,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
             parameter<KtModifierKeywordToken>("modifier2")
         }
         val REDUNDANT_OPEN_IN_INTERFACE by warning<FirSourceElement, KtModifierListOwner>(PositioningStrategy.MODALITY_MODIFIER)
+    }
 
-    // Applicability
+    group("Applicability") {
         val NONE_APPLICABLE by error<FirSourceElement, PsiElement> {
             parameter<Collection<AbstractFirBasedSymbol<*>>>("candidates")
         }
@@ -149,16 +158,18 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val INAPPLICABLE_LATEINIT_MODIFIER by error<FirSourceElement, PsiElement>() {
             parameter<String>("reason")
         }
+    }
 
-    // Ambiguity
+    group("Ambiguity") {
         val AMBIGUITY by error<FirSourceElement, PsiElement> {
             parameter<Collection<AbstractFirBasedSymbol<*>>>("candidates")
         }
         val ASSIGN_OPERATOR_AMBIGUITY by error<FirSourceElement, PsiElement> {
             parameter<Collection<AbstractFirBasedSymbol<*>>>("candidates")
         }
+    }
 
-    // Types & type parameters
+    group("Types & type parameters") {
         val TYPE_MISMATCH by error<FirSourceElement, PsiElement> {
             parameter<ConeKotlinType>("expectedType")
             parameter<ConeKotlinType>("actualType")
@@ -195,8 +206,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
             parameter<String>("variableType") // TODO use ConeType instead of String
             parameter<FirMemberDeclaration>("targetVariable")
         }
+    }
 
-    // Redeclarations
+    group("Redeclarations") {
         val MANY_COMPANION_OBJECTS by error<FirSourceElement, PsiElement>()
         val CONFLICTING_OVERLOADS by error<FirSourceElement, PsiElement>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT) {
             parameter<String>("conflictingOverloads") // TODO use Collection<Symbol> instead of String
@@ -205,16 +217,18 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
             parameter<String>("conflictingDeclaration") // TODO use Collection<Symbol> instead of String
         }
         val ANY_METHOD_IMPLEMENTED_IN_INTERFACE by error<FirSourceElement, PsiElement>()
+    }
 
-    // Invalid local declarations
+    group("Invalid local declarations") {
         val LOCAL_OBJECT_NOT_ALLOWED by error<FirSourceElement, KtNamedDeclaration>(PositioningStrategy.DECLARATION_NAME) {
             parameter<Name>("objectName")
         }
         val LOCAL_INTERFACE_NOT_ALLOWED by error<FirSourceElement, KtNamedDeclaration>(PositioningStrategy.DECLARATION_NAME) {
             parameter<Name>("interfaceName")
         }
+    }
 
-    // Functions
+    group("Functions") {
         val ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS by error<FirSourceElement, KtFunction>(PositioningStrategy.MODALITY_MODIFIER) {
             parameter<FirMemberDeclaration>("function")
             parameter<FirMemberDeclaration>("containingClass") // TODO use FirClass instead of FirMemberDeclaration
@@ -240,8 +254,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val ANONYMOUS_FUNCTION_PARAMETER_WITH_DEFAULT_VALUE by error<FirSourceElement, KtParameter>(PositioningStrategy.PARAMETER_DEFAULT_VALUE)
         val USELESS_VARARG_ON_PARAMETER by warning<FirSourceElement, KtParameter>()
 
+    }
 
-    // Properties & accessors
+    group("Properties & accessors") {
         val ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS by error<FirSourceElement, KtModifierListOwner>(PositioningStrategy.MODALITY_MODIFIER) {
             parameter<FirMemberDeclaration>("property")
             parameter<FirMemberDeclaration>("containingClass") // TODO use FirClass instead of FirMemberDeclaration
@@ -261,15 +276,17 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY by error<FirSourceElement, PsiElement>()
         val PRIVATE_SETTER_FOR_OPEN_PROPERTY by error<FirSourceElement, PsiElement>()
         val EXPECTED_PRIVATE_DECLARATION by error<FirSourceElement, KtModifierListOwner>(PositioningStrategy.VISIBILITY_MODIFIER)
+    }
 
-    // Multi-platform projects
+    group("Multi-platform projects") {
         val EXPECTED_DECLARATION_WITH_BODY by error<FirSourceElement, KtDeclaration>(PositioningStrategy.DECLARATION_SIGNATURE)
         val EXPECTED_PROPERTY_INITIALIZER by error<FirSourceElement, KtExpression>()
         // TODO: need to cover `by` as well as delegate expression
         val EXPECTED_DELEGATED_PROPERTY by error<FirSourceElement, KtPropertyDelegate>()
+    }
 
 
-    // Destructuring declaration
+    group("Destructuring declaration") {
         val INITIALIZER_REQUIRED_FOR_DESTRUCTURING_DECLARATION by error<FirSourceElement, KtDestructuringDeclaration>()
         val COMPONENT_FUNCTION_MISSING by error<FirSourceElement, PsiElement> {
             parameter<Name>("missingFunctionName")
@@ -281,8 +298,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         }
         // TODO: val COMPONENT_FUNCTION_ON_NULLABLE by ...
         // TODO: val COMPONENT_FUNCTION_RETURN_TYPE_MISMATCH by ...
+    }
 
-    // Control flow diagnostics
+    group("Control flow diagnostics") {
         val UNINITIALIZED_VARIABLE by error<FirSourceElement, PsiElement> {
             parameter<FirPropertySymbol>("variable")
         }
@@ -295,8 +313,9 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
             parameter<AbstractFirBasedSymbol<*>>("lambda")
         }
         val WRONG_IMPLIES_CONDITION by warning<FirSourceElement, PsiElement>()
+    }
 
-    // Extended checkers group
+    group(" Extended checkers") {
         val REDUNDANT_VISIBILITY_MODIFIER by warning<FirSourceElement, KtModifierListOwner>(PositioningStrategy.VISIBILITY_MODIFIER)
         val REDUNDANT_MODALITY_MODIFIER by warning<FirSourceElement, KtModifierListOwner>(PositioningStrategy.MODALITY_MODIFIER)
         val REDUNDANT_RETURN_UNIT_TYPE by warning<FirSourceElement, PsiTypeElement>()
@@ -314,6 +333,7 @@ val DIAGNOSTICS_LIST = DiagnosticListBuilder.buildDiagnosticList {
         val VARIABLE_NEVER_READ by warning<FirSourceElement, KtNamedDeclaration>(PositioningStrategy.DECLARATION_NAME)
         val USELESS_CALL_ON_NOT_NULL by warning<FirSourceElement, PsiElement>()
     }
+}
 
 private inline fun <reified P : PsiElement> DiagnosticListBuilder.exposedVisibilityError(
     positioningStrategy: PositioningStrategy = PositioningStrategy.DEFAULT

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -40,8 +40,11 @@ import org.jetbrains.kotlin.psi.KtTypeReference
  */
 
 object FirErrors {
+    // Miscellaneous
     val SYNTAX by error0<FirSourceElement, PsiElement>()
     val OTHER_ERROR by error0<FirSourceElement, PsiElement>()
+
+    // General syntax
     val ILLEGAL_CONST_EXPRESSION by error0<FirSourceElement, PsiElement>()
     val ILLEGAL_UNDERSCORE by error0<FirSourceElement, PsiElement>()
     val EXPRESSION_REQUIRED by error0<FirSourceElement, PsiElement>()
@@ -50,6 +53,8 @@ object FirErrors {
     val VARIABLE_EXPECTED by error0<FirSourceElement, PsiElement>()
     val RETURN_NOT_ALLOWED by error0<FirSourceElement, PsiElement>()
     val DELEGATION_IN_INTERFACE by error0<FirSourceElement, PsiElement>()
+
+    // Unresolved
     val HIDDEN by error1<FirSourceElement, PsiElement, AbstractFirBasedSymbol<*>>()
     val UNRESOLVED_REFERENCE by error1<FirSourceElement, PsiElement, String>()
     val UNRESOLVED_LABEL by error0<FirSourceElement, PsiElement>()
@@ -58,10 +63,14 @@ object FirErrors {
     val UNKNOWN_CALLABLE_KIND by error0<FirSourceElement, PsiElement>()
     val MISSING_STDLIB_CLASS by error0<FirSourceElement, PsiElement>()
     val NO_THIS by error0<FirSourceElement, PsiElement>()
+
+    // Super
     val SUPER_IS_NOT_AN_EXPRESSION by error0<FirSourceElement, PsiElement>()
     val SUPER_NOT_AVAILABLE by error0<FirSourceElement, PsiElement>()
     val ABSTRACT_SUPER_CALL by error0<FirSourceElement, PsiElement>()
     val INSTANCE_ACCESS_BEFORE_SUPER_CALL by error1<FirSourceElement, PsiElement, String>()
+
+    // Supertypes
     val TYPE_PARAMETER_AS_SUPERTYPE by error0<FirSourceElement, PsiElement>()
     val ENUM_AS_SUPERTYPE by error0<FirSourceElement, PsiElement>()
     val RECURSION_IN_SUPERTYPES by error0<FirSourceElement, PsiElement>()
@@ -73,6 +82,8 @@ object FirErrors {
     val CLASS_IN_SUPERTYPE_FOR_ENUM by error0<FirSourceElement, PsiElement>()
     val SEALED_SUPERTYPE by error0<FirSourceElement, PsiElement>()
     val SEALED_SUPERTYPE_IN_LOCAL_CLASS by error0<FirSourceElement, PsiElement>()
+
+    //  Constructor problems
     val CONSTRUCTOR_IN_OBJECT by error0<FirSourceElement, KtDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val CONSTRUCTOR_IN_INTERFACE by error0<FirSourceElement, KtDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val NON_PRIVATE_CONSTRUCTOR_IN_ENUM by error0<FirSourceElement, PsiElement>()
@@ -84,6 +95,8 @@ object FirErrors {
     val PRIMARY_CONSTRUCTOR_REQUIRED_FOR_DATA_CLASS by warning0<FirSourceElement, PsiElement>()
     val EXPLICIT_DELEGATION_CALL_REQUIRED by warning0<FirSourceElement, PsiElement>(SourceElementPositioningStrategies.SECONDARY_CONSTRUCTOR_DELEGATION_CALL)
     val SEALED_CLASS_CONSTRUCTOR_CALL by error0<FirSourceElement, PsiElement>()
+
+    // Annotations
     val ANNOTATION_ARGUMENT_KCLASS_LITERAL_OF_TYPE_PARAMETER_ERROR by error0<FirSourceElement, KtExpression>()
     val ANNOTATION_ARGUMENT_MUST_BE_CONST by error0<FirSourceElement, KtExpression>()
     val ANNOTATION_ARGUMENT_MUST_BE_ENUM_CONST by error0<FirSourceElement, KtExpression>()
@@ -97,6 +110,8 @@ object FirErrors {
     val NOT_AN_ANNOTATION_CLASS by error1<FirSourceElement, PsiElement, String>()
     val NULLABLE_TYPE_OF_ANNOTATION_MEMBER by error0<FirSourceElement, KtTypeReference>()
     val VAR_ANNOTATION_PARAMETER by error0<FirSourceElement, KtParameter>(SourceElementPositioningStrategies.VAL_OR_VAR_NODE)
+
+    // Exposed visibility group
     val EXPOSED_TYPEALIAS_EXPANDED_TYPE by error3<FirSourceElement, KtNamedDeclaration, FirEffectiveVisibility, FirMemberDeclaration, FirEffectiveVisibility>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val EXPOSED_FUNCTION_RETURN_TYPE by error3<FirSourceElement, KtNamedDeclaration, FirEffectiveVisibility, FirMemberDeclaration, FirEffectiveVisibility>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val EXPOSED_RECEIVER_TYPE by error3<FirSourceElement, KtTypeReference, FirEffectiveVisibility, FirMemberDeclaration, FirEffectiveVisibility>()
@@ -105,17 +120,25 @@ object FirErrors {
     val EXPOSED_SUPER_INTERFACE by error3<FirSourceElement, KtTypeReference, FirEffectiveVisibility, FirMemberDeclaration, FirEffectiveVisibility>()
     val EXPOSED_SUPER_CLASS by error3<FirSourceElement, KtTypeReference, FirEffectiveVisibility, FirMemberDeclaration, FirEffectiveVisibility>()
     val EXPOSED_TYPE_PARAMETER_BOUND by error3<FirSourceElement, KtTypeReference, FirEffectiveVisibility, FirMemberDeclaration, FirEffectiveVisibility>()
+
+    // Modifiers
     val INAPPLICABLE_INFIX_MODIFIER by error1<FirSourceElement, PsiElement, String>()
     val REPEATED_MODIFIER by error1<FirSourceElement, PsiElement, KtModifierKeywordToken>()
     val REDUNDANT_MODIFIER by error2<FirSourceElement, PsiElement, KtModifierKeywordToken, KtModifierKeywordToken>()
     val DEPRECATED_MODIFIER_PAIR by error2<FirSourceElement, PsiElement, KtModifierKeywordToken, KtModifierKeywordToken>()
     val INCOMPATIBLE_MODIFIERS by error2<FirSourceElement, PsiElement, KtModifierKeywordToken, KtModifierKeywordToken>()
     val REDUNDANT_OPEN_IN_INTERFACE by warning0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.MODALITY_MODIFIER)
+
+    // Applicability
     val NONE_APPLICABLE by error1<FirSourceElement, PsiElement, Collection<AbstractFirBasedSymbol<*>>>()
     val INAPPLICABLE_CANDIDATE by error1<FirSourceElement, PsiElement, AbstractFirBasedSymbol<*>>()
     val INAPPLICABLE_LATEINIT_MODIFIER by error1<FirSourceElement, PsiElement, String>()
+
+    // Ambiguity
     val AMBIGUITY by error1<FirSourceElement, PsiElement, Collection<AbstractFirBasedSymbol<*>>>()
     val ASSIGN_OPERATOR_AMBIGUITY by error1<FirSourceElement, PsiElement, Collection<AbstractFirBasedSymbol<*>>>()
+
+    // Types & type parameters
     val TYPE_MISMATCH by error2<FirSourceElement, PsiElement, ConeKotlinType, ConeKotlinType>()
     val RECURSION_IN_IMPLICIT_TYPES by error0<FirSourceElement, PsiElement>()
     val INFERENCE_ERROR by error0<FirSourceElement, PsiElement>()
@@ -132,12 +155,18 @@ object FirErrors {
     val RETURN_TYPE_MISMATCH_ON_OVERRIDE by error2<FirSourceElement, PsiElement, String, FirMemberDeclaration>()
     val PROPERTY_TYPE_MISMATCH_ON_OVERRIDE by error2<FirSourceElement, PsiElement, String, FirMemberDeclaration>()
     val VAR_TYPE_MISMATCH_ON_OVERRIDE by error2<FirSourceElement, PsiElement, String, FirMemberDeclaration>()
+
+    // Redeclarations
     val MANY_COMPANION_OBJECTS by error0<FirSourceElement, PsiElement>()
     val CONFLICTING_OVERLOADS by error1<FirSourceElement, PsiElement, String>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
     val REDECLARATION by error1<FirSourceElement, PsiElement, String>()
     val ANY_METHOD_IMPLEMENTED_IN_INTERFACE by error0<FirSourceElement, PsiElement>()
+
+    // Invalid local declarations
     val LOCAL_OBJECT_NOT_ALLOWED by error1<FirSourceElement, KtNamedDeclaration, Name>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val LOCAL_INTERFACE_NOT_ALLOWED by error1<FirSourceElement, KtNamedDeclaration, Name>(SourceElementPositioningStrategies.DECLARATION_NAME)
+
+    // Functions
     val ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS by error2<FirSourceElement, KtFunction, FirMemberDeclaration, FirMemberDeclaration>(SourceElementPositioningStrategies.MODALITY_MODIFIER)
     val ABSTRACT_FUNCTION_WITH_BODY by error1<FirSourceElement, KtFunction, FirMemberDeclaration>(SourceElementPositioningStrategies.MODALITY_MODIFIER)
     val NON_ABSTRACT_FUNCTION_WITH_NO_BODY by error1<FirSourceElement, KtFunction, FirMemberDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
@@ -146,6 +175,8 @@ object FirErrors {
     val FUNCTION_DECLARATION_WITH_NO_NAME by error0<FirSourceElement, KtFunction>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val ANONYMOUS_FUNCTION_PARAMETER_WITH_DEFAULT_VALUE by error0<FirSourceElement, KtParameter>(SourceElementPositioningStrategies.PARAMETER_DEFAULT_VALUE)
     val USELESS_VARARG_ON_PARAMETER by warning0<FirSourceElement, KtParameter>()
+
+    // Properties & accessors
     val ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS by error2<FirSourceElement, KtModifierListOwner, FirMemberDeclaration, FirMemberDeclaration>(SourceElementPositioningStrategies.MODALITY_MODIFIER)
     val PRIVATE_PROPERTY_IN_INTERFACE by error0<FirSourceElement, KtProperty>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
     val ABSTRACT_PROPERTY_WITH_INITIALIZER by error0<FirSourceElement, KtExpression>()
@@ -158,16 +189,24 @@ object FirErrors {
     val PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY by error0<FirSourceElement, PsiElement>()
     val PRIVATE_SETTER_FOR_OPEN_PROPERTY by error0<FirSourceElement, PsiElement>()
     val EXPECTED_PRIVATE_DECLARATION by error0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
+
+    // Multi-platform projects
     val EXPECTED_DECLARATION_WITH_BODY by error0<FirSourceElement, KtDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
     val EXPECTED_PROPERTY_INITIALIZER by error0<FirSourceElement, KtExpression>()
     val EXPECTED_DELEGATED_PROPERTY by error0<FirSourceElement, KtPropertyDelegate>()
+
+    // Destructuring declaration
     val INITIALIZER_REQUIRED_FOR_DESTRUCTURING_DECLARATION by error0<FirSourceElement, KtDestructuringDeclaration>()
     val COMPONENT_FUNCTION_MISSING by error2<FirSourceElement, PsiElement, Name, FirTypeRef>()
     val COMPONENT_FUNCTION_AMBIGUITY by error2<FirSourceElement, PsiElement, Name, Collection<AbstractFirBasedSymbol<*>>>()
+
+    // Control flow diagnostics
     val UNINITIALIZED_VARIABLE by error1<FirSourceElement, PsiElement, FirPropertySymbol>()
     val WRONG_INVOCATION_KIND by warning3<FirSourceElement, PsiElement, AbstractFirBasedSymbol<*>, EventOccurrencesRange, EventOccurrencesRange>()
     val LEAKED_IN_PLACE_LAMBDA by error1<FirSourceElement, PsiElement, AbstractFirBasedSymbol<*>>()
     val WRONG_IMPLIES_CONDITION by warning0<FirSourceElement, PsiElement>()
+
+    //  Extended checkers
     val REDUNDANT_VISIBILITY_MODIFIER by warning0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
     val REDUNDANT_MODALITY_MODIFIER by warning0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.MODALITY_MODIFIER)
     val REDUNDANT_RETURN_UNIT_TYPE by warning0<FirSourceElement, PsiTypeElement>()
@@ -184,4 +223,5 @@ object FirErrors {
     val VARIABLE_INITIALIZER_IS_REDUNDANT by warning0<FirSourceElement, PsiElement>()
     val VARIABLE_NEVER_READ by warning0<FirSourceElement, KtNamedDeclaration>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val USELESS_CALL_ON_NOT_NULL by warning0<FirSourceElement, PsiElement>()
+
 }