[FIR] Render backing fields by FirRenderer

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/backingFieldModifiers.fir.txt

@@ -5,24 +5,31 @@ FILE: backingFieldModifiers.kt
         }
 
         public final val a: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val b: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val c: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val d: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val e: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val f: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val g: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/backingFieldVisibility.fir.txt

@@ -6,15 +6,19 @@ FILE: A.kt
         }
 
         public final val a: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(1)
             public get(): R|kotlin/Number|
 
         public final val b: R|kotlin/Number|
+            internal <explicit backing field>: R|kotlin/Int| = Int(2)
             public get(): R|kotlin/Number|
 
         public final val c: R|kotlin/Number|
+            protected <explicit backing field>: R|kotlin/Int| = Int(3)
             public get(): R|kotlin/Number|
 
         public final val d: R|kotlin/Number|
+            public <explicit backing field>: R|kotlin/Int| = Int(5)
             public get(): R|kotlin/Number|
 
         public final fun rest(): R|kotlin/Unit| {

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/backingFieldWithSmartTypeParameters.fir.txt

@@ -1,5 +1,6 @@
 FILE: backingFieldWithSmartTypeParameters.kt
     public final val items: R|kotlin/collections/List<kotlin/String>|
+        private <explicit backing field>: R|kotlin/collections/MutableList<kotlin/String>| = R|kotlin/collections/mutableListOf|<R|kotlin/String|>()
         public get(): R|kotlin/collections/List<kotlin/String>|
     public final fun test(): R|kotlin/Unit| {
         R|/items|.R|SubstitutionOverride<kotlin/collections/MutableList.add: R|kotlin/Boolean|>|(String(one more item))

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/explicitBackingFieldInInterface.fir.txt

@@ -1,6 +1,7 @@
 FILE: explicitBackingFieldInInterface.kt
     public abstract interface I : R|kotlin/Any| {
         public abstract val it: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(10)
             public get(): R|kotlin/Number|
 
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/explicitBackingFieldType.fir.txt

@@ -8,31 +8,39 @@ FILE: explicitBackingFieldType.kt
             public get(): R|kotlin/Int|
 
         public final val it: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(4)
             public get(): R|kotlin/Number|
 
         public final val joke: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/String| = String(Haha)
             public get(): R|kotlin/Number|
 
         public final val incompatible: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Any?| = Int(42)
             public get(): R|kotlin/Number|
 
         public final val customGetterNeeded: R|kotlin/Int|
+            private <explicit backing field>: R|kotlin/Number| = Int(42)
             public get(): R|kotlin/Int|
 
         public final val invertedTypes: R|kotlin/Int|
+            private <explicit backing field>: R|kotlin/Number| = Int(42)
             public get(): R|kotlin/Int| {
                 ^ Int(30)
             }
 
         public final val uninitialized: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int|
             public get(): R|kotlin/Number|
 
         public final val uninitializedWithGetter: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int|
             public get(): R|kotlin/Number| {
                 ^ Int(2)
             }
 
         public final val initiaizedWithExplicitBackingField: R|kotlin/collections/List<kotlin/Int>| = R|kotlin/collections/listOf|<R|kotlin/Int|>(vararg(Int(1), Int(2)))
+            private <explicit backing field>: R|kotlin/collections/MutableList<kotlin/Int>|
             public get(): R|kotlin/collections/List<kotlin/Int>|
 
         public final val p: R|kotlin/Int| = Int(5)
@@ -41,6 +49,7 @@ FILE: explicitBackingFieldType.kt
             }
 
         public final var setterNeeded: R|kotlin/Int|
+            private <explicit backing field>: R|kotlin/String| = String(test)
             public get(): R|kotlin/Int| {
                 ^ this@R|/A|.F|/A.setterNeeded|.R|kotlin/String.length|
             }

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/explicitBackingFieldsWithDelegates.fir.txt

@@ -3,6 +3,7 @@ FILE: explicitBackingFieldsWithDelegates.kt
         ^ (Int(2) as R|kotlin/Number|)
     }
     )
+        private <explicit backing field>: R|kotlin/Int| = Int(10)
         public get(): R|kotlin/Number| {
             ^ D|/thingWithDelefate|.R|kotlin/getValue|<R|kotlin/Number|>(Null(null), ::R|/thingWithDelefate|)
         }

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/filePrivateBackingFieldAccess.fir.txt

@@ -1,5 +1,6 @@
 FILE: filePrivateBackingFieldAccess.kt
     public final val list: R|kotlin/collections/List<kotlin/String>|
+        private <explicit backing field>: R|kotlin/collections/MutableList<kotlin/String>| = R|kotlin/collections/mutableListOf|<R|kotlin/String|>()
         public get(): R|kotlin/collections/List<kotlin/String>|
     public final fun add(s: R|kotlin/String|): R|kotlin/Unit| {
         R|/list|.R|SubstitutionOverride<kotlin/collections/MutableList.add: R|kotlin/Boolean|>|(R|<local>/s|)

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/lateinitBackingFields.fir.txt

@@ -1,5 +1,6 @@
 FILE: lateinitBackingFields.kt
     public final var that: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/String|
         public get(): R|kotlin/Int| {
             ^ F|/that|.R|kotlin/String.length|
         }
@@ -11,18 +12,22 @@ FILE: lateinitBackingFields.kt
         R|kotlin/io/println|(R|/that|)
     }
     public final lateinit var number: R|kotlin/Number|
+        private <explicit backing field>: R|kotlin/Int| = Int(4)
         public get(): R|kotlin/Number|
         public set(value: R|kotlin/Number|): R|kotlin/Unit| {
             F|/number| = Int(10)
         }
     public final val something: R|kotlin/Number|
+        private <explicit backing field>: R|kotlin/Int| = Int(4)
         public get(): R|kotlin/Number|
     public final lateinit var oneMore: R|kotlin/Number|
+        private <explicit backing field>: R|kotlin/Int| = Int(4)
         public get(): R|kotlin/Number|
         public set(value: R|kotlin/Number|): R|kotlin/Unit| {
             F|/oneMore| = Int(10)
         }
     public final var thingWithNullableField: R|kotlin/Number|
+        private <explicit backing field>: R|kotlin/String?|
         public get(): R|kotlin/Number| {
             ^ Int(20)
         }

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/localVariablesWithBackingFields.fir.txt

@@ -1,5 +1,6 @@
 FILE: localVariablesWithBackingFields.kt
     public final val that: R|kotlin/Number|
+        private <explicit backing field>: R|kotlin/Int| = Int(239)
         public get(): R|kotlin/Number|
     public final fun test(): R|kotlin/Unit| {
         lval a: R|kotlin/Number|
@@ -19,12 +20,14 @@ FILE: localVariablesWithBackingFields.kt
             ^ Int(2)
         }
         )
+            private <explicit backing field>: R|kotlin/Int| = Int(10)
             public get(): R|kotlin/Number| {
                 ^ this@R|/A|.D|/A.c|.R|kotlin/getValue|<R|kotlin/Int|>(this@R|/A|, ::R|/A.c|)
             }
 
     }
     public final val R|A|.cc: R|kotlin/Number|
+        private <explicit backing field>: R|kotlin/Int| = Int(10)
         public get(): R|kotlin/Number|
     public final fun R|A|.cc(): R|kotlin/Unit| {
         lval it: <ERROR TYPE REF: Ambiguity: plus, [kotlin/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/sequences/plus]> = <Unresolved name: a>#.<Ambiguity: plus, [kotlin/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/collections/plus, kotlin/sequences/plus]>#(Int(2))

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/overriddenPropertiesWithExplicitBackingFields.fir.txt

@@ -5,6 +5,7 @@ FILE: overriddenPropertiesWithExplicitBackingFields.kt
         }
 
         public open var it: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(3)
             public get(): R|kotlin/Number|
             public set(value: R|kotlin/Number|): R|kotlin/Unit| {
                 this@R|/A|.F|/A.it| = R|<local>/value|.R|kotlin/Number.toInt|()

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/propertyTypeNarrowing.fir.txt

@@ -5,6 +5,7 @@ FILE: propertyTypeNarrowing.kt
         }
 
         public final val it: R|kotlin/Number|
+            private <explicit backing field>: R|kotlin/Int| = Int(4)
             public get(): R|kotlin/Number|
 
         public final fun test(): R|kotlin/Int| {

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/randomWeirdBackingFields.fir.txt

@@ -5,6 +5,7 @@ FILE: randomWeirdBackingFields.kt
         }
 
         public abstract val foo: R|kotlin/collections/List<kotlin/Int>|
+            internal <explicit backing field>: R|kotlin/collections/MutableList<kotlin/Int>| = R|kotlin/collections/mutableListOf|<R|kotlin/Int|>()
             public get(): R|kotlin/collections/List<kotlin/Int>|
 
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/redundantExplicitBackingField.fir.txt

@@ -1,3 +1,4 @@
 FILE: redundantExplicitBackingField.kt
     public final val it: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Int| = Int(42)
         public get(): R|kotlin/Int|

compiler/fir/analysis-tests/testData/resolveWithStdlib/properties/backingField/untypedPropertyWithBackingFieldUsage.fir.txt

@@ -16,38 +16,48 @@ FILE: untypedPropertyWithBackingFieldUsage.kt
             ^ F|/simpleTypeExpression|
         }
     public final val withFieldNoTypeBlock: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ <Unresolved name: field>#.R|kotlin/text/toInt|()
         }
     public final val withFieldNoTypeExpression: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ <Unresolved name: field>#.R|kotlin/text/toInt|()
         }
     public final val withFieldTypeBlock: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ F|/withFieldTypeBlock|.R|kotlin/Double.toInt|()
         }
     public final val withFieldTypeExpression: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ F|/withFieldTypeExpression|.R|kotlin/Double.toInt|()
         }
     public final val minimalFieldWithInitializer: <ERROR TYPE REF: Cannot infer variable type without initializer / getter / delegate>
+        private <explicit backing field>: R|kotlin/Int| = Int(1)
         public get(): <ERROR TYPE REF: Cannot infer variable type without initializer / getter / delegate>
     public final val minimalFieldWithNoInitializer: <ERROR TYPE REF: Cannot infer variable type without initializer / getter / delegate>
+        private <explicit backing field>: R|kotlin/Int|
         public get(): <ERROR TYPE REF: Cannot infer variable type without initializer / getter / delegate>
     public final val constWithFieldNoTypeBlock: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ Int(10)
         }
     public final val constWithFieldNoTypeExpression: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ Int(10)
         }
     public final val constWithFieldTypeBlock: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ Int(10)
         }
     public final val constWithFieldTypeExpression: R|kotlin/Int|
+        private <explicit backing field>: R|kotlin/Double| = Double(3.14)
         public get(): R|kotlin/Int| {
             ^ Int(10)
         }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirRenderer.kt

@@ -518,6 +518,12 @@ class FirRenderer(builder: StringBuilder, private val mode: RenderMode = RenderM
         if (!mode.renderPropertyAccessors) return
         println()
         pushIndent()
+
+        if (property.hasExplicitBackingField) {
+            property.backingField?.accept(this)
+            println()
+        }
+
         property.getter?.accept(this)
         if (property.getter?.body == null) {
             println()
@@ -531,6 +537,17 @@ class FirRenderer(builder: StringBuilder, private val mode: RenderMode = RenderM
         popIndent()
     }
 
+    override fun visitBackingField(backingField: FirBackingField) {
+        print(backingField.visibility.asString() + " ")
+        print("<explicit backing field>: ")
+        backingField.returnTypeRef.accept(this)
+
+        backingField.initializer?.let {
+            print(" = ")
+            it.accept(this)
+        }
+    }
+
     override fun visitSimpleFunction(simpleFunction: FirSimpleFunction) {
         visitCallableDeclaration(simpleFunction)
         simpleFunction.body?.renderBody()