FIR checker: introduce NO_(GET|SET)_METHOD

Besides introducing new diagnostics, this commit unifies source usages
for array accesses in PSI & LT.

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

@@ -49,6 +49,7 @@ enum class PositioningStrategy(private val strategy: String? = null) {
     PRIVATE_MODIFIER,
     COMPANION_OBJECT,
     CONST_MODIFIER,
+    ARRAY_ACCESS
 
     ;
 

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

@@ -515,6 +515,11 @@ object DIAGNOSTICS_LIST : DiagnosticList() {
         }
     }
 
+    val CONVENTIONS by object : DiagnosticGroup("Conventions") {
+        val NO_GET_METHOD by error<FirSourceElement, KtArrayAccessExpression>(PositioningStrategy.ARRAY_ACCESS)
+        val NO_SET_METHOD by error<FirSourceElement, KtArrayAccessExpression>(PositioningStrategy.ARRAY_ACCESS)
+    }
+
     val EXTENDED_CHECKERS by object : DiagnosticGroup("Extended checkers") {
         val REDUNDANT_VISIBILITY_MODIFIER by warning<FirSourceElement, KtModifierListOwner>(PositioningStrategy.VISIBILITY_MODIFIER)
         val REDUNDANT_MODALITY_MODIFIER by warning<FirSourceElement, KtModifierListOwner>(PositioningStrategy.MODALITY_MODIFIER)

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

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.psi.KtArrayAccessExpression
 import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtDestructuringDeclaration
@@ -307,6 +308,10 @@ object FirErrors {
     // Function contracts
     val ERROR_IN_CONTRACT_DESCRIPTION by error1<FirSourceElement, KtElement, String>(SourceElementPositioningStrategies.SELECTOR_BY_QUALIFIED)
 
+    // Conventions
+    val NO_GET_METHOD by error0<FirSourceElement, KtArrayAccessExpression>(SourceElementPositioningStrategies.ARRAY_ACCESS)
+    val NO_SET_METHOD by error0<FirSourceElement, KtArrayAccessExpression>(SourceElementPositioningStrategies.ARRAY_ACCESS)
+
     // Extended checkers
     val REDUNDANT_VISIBILITY_MODIFIER by warning0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
     val REDUNDANT_MODALITY_MODIFIER by warning0<FirSourceElement, KtModifierListOwner>(SourceElementPositioningStrategies.MODALITY_MODIFIER)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirConventionFunctionCallChecker.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.analysis.checkers.expression
+
+import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.expressions.FirFunctionCall
+import org.jetbrains.kotlin.fir.references.FirErrorNamedReference
+import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnresolvedNameError
+import org.jetbrains.kotlin.util.OperatorNameConventions
+
+object FirConventionFunctionCallChecker : FirFunctionCallChecker() {
+    override fun check(expression: FirFunctionCall, context: CheckerContext, reporter: DiagnosticReporter) {
+        val calleeReference = expression.calleeReference as? FirErrorNamedReference ?: return
+        val diagnostic = calleeReference.diagnostic as? ConeUnresolvedNameError ?: return
+
+        if (expression.calleeReference.source?.kind == FirFakeSourceElementKind.ArrayAccessNameReference) {
+            when (diagnostic.name) {
+                OperatorNameConventions.GET -> reporter.reportOn(calleeReference.source, FirErrors.NO_GET_METHOD, context)
+                OperatorNameConventions.SET -> reporter.reportOn(calleeReference.source, FirErrors.NO_SET_METHOD, context)
+            }
+        }
+    }
+}

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/components/ErrorNodeDiagnosticCollectorComponent.kt

@@ -39,6 +39,10 @@ class ErrorNodeDiagnosticCollectorComponent(collector: AbstractDiagnosticCollect
             ?: errorNamedReference.source ?: return
         // Don't report duplicated unresolved reference on annotation entry (already reported on its type)
         if (source.elementType == KtNodeTypes.ANNOTATION_ENTRY && errorNamedReference.diagnostic is ConeUnresolvedNameError) return
+        // Already reported in FirConventionFunctionCallChecker
+        if (errorNamedReference.source?.kind == FirFakeSourceElementKind.ArrayAccessNameReference &&
+            errorNamedReference.diagnostic is ConeUnresolvedNameError
+        ) return
         reportFirDiagnostic(errorNamedReference.diagnostic, source, reporter, data)
     }
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt

@@ -139,6 +139,8 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NOT_AN_ANNOTATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NOT_A_LOOP_LABEL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NOT_A_SUPERTYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NO_ELSE_IN_WHEN
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NO_GET_METHOD
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NO_SET_METHOD
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NO_THIS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NULLABLE_TYPE_IN_CLASS_LITERAL_LHS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.NULLABLE_TYPE_OF_ANNOTATION_MEMBER
@@ -679,6 +681,10 @@ class FirDefaultErrorMessages : DefaultErrorMessages.Extension {
             // Function contracts
             map.put(ERROR_IN_CONTRACT_DESCRIPTION, "Error in contract description", TO_STRING)
 
+            // Conventions
+            map.put(NO_GET_METHOD, "No get method providing array access")
+            map.put(NO_SET_METHOD, "No set method providing array access")
+
             // Extended checkers group
             map.put(REDUNDANT_VISIBILITY_MODIFIER, "Redundant visibility modifier")
             map.put(REDUNDANT_MODALITY_MODIFIER, "Redundant modality modifier")

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategies.kt

@@ -415,6 +415,17 @@ object LightTreePositioningStrategies {
             return markElement(tree.ifKeyword(node) ?: node, startOffset, endOffset, tree, node)
         }
     }
+
+    val ARRAY_ACCESS = object : LightTreePositioningStrategy() {
+        override fun mark(
+            node: LighterASTNode,
+            startOffset: Int,
+            endOffset: Int,
+            tree: FlyweightCapableTreeStructure<LighterASTNode>
+        ): List<TextRange> {
+            return markElement(tree.findChildByType(node, KtNodeTypes.INDICES)!!, startOffset, endOffset, tree, node)
+        }
+    }
 }
 
 fun FirSourceElement.hasValOrVar(): Boolean =

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/SourceElementPositioningStrategies.kt

@@ -143,4 +143,8 @@ object SourceElementPositioningStrategies {
         PositioningStrategies.IF_EXPRESSION
     )
 
+    val ARRAY_ACCESS = SourceElementPositioningStrategy(
+        LightTreePositioningStrategies.ARRAY_ACCESS,
+        PositioningStrategies.ARRAY_ACCESS
+    )
 }