[FIR] Don't create backing field for property without explicit type

#KT-41977 Fixed

compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldInProperty.kt

@@ -0,0 +1,15 @@
+// ISSUE: KT-41977
+
+class A {
+    val field: String = "" // (1)
+
+    val x
+        get() = field.length // should be ok, resolve to (1)
+}
+
+class B {
+    val field: String = ""
+
+    val x: Int
+        get() = field.<!UNRESOLVED_REFERENCE!>length<!> // should be an error
+}

compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldInProperty.txt

@@ -0,0 +1,29 @@
+FILE: noBackingFieldInProperty.kt
+    public final class A : R|kotlin/Any| {
+        public constructor(): R|A| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final val field: R|kotlin/String| = String()
+            public get(): R|kotlin/String|
+
+        public final val x: R|kotlin/Int|
+            public get(): R|kotlin/Int| {
+                ^ this@R|/A|.R|/A.field|.R|kotlin/String.length|
+            }
+
+    }
+    public final class B : R|kotlin/Any| {
+        public constructor(): R|B| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final val field: R|kotlin/String| = String()
+            public get(): R|kotlin/String|
+
+        public final val x: R|kotlin/Int|
+            public get(): R|kotlin/Int| {
+                ^ this@R|/B|.F|/B.x|.<Unresolved name: length>#
+            }
+
+    }

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirDiagnosticsTestGenerated.java

@@ -2062,6 +2062,11 @@ public class FirDiagnosticsTestGenerated extends AbstractFirDiagnosticsTest {
             runTest("compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldForExtension.kt");
         }
 
+        @TestMetadata("noBackingFieldInProperty.kt")
+        public void testNoBackingFieldInProperty() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldInProperty.kt");
+        }
+
         @TestMetadata("syntheticPropertiesForJavaAnnotations.kt")
         public void testSyntheticPropertiesForJavaAnnotations() throws Exception {
             runTest("compiler/fir/analysis-tests/testData/resolve/properties/syntheticPropertiesForJavaAnnotations.kt");

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirDiagnosticsWithLightTreeTestGenerated.java

@@ -2062,6 +2062,11 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
             runTest("compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldForExtension.kt");
         }
 
+        @TestMetadata("noBackingFieldInProperty.kt")
+        public void testNoBackingFieldInProperty() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldInProperty.kt");
+        }
+
         @TestMetadata("syntheticPropertiesForJavaAnnotations.kt")
         public void testSyntheticPropertiesForJavaAnnotations() throws Exception {
             runTest("compiler/fir/analysis-tests/testData/resolve/properties/syntheticPropertiesForJavaAnnotations.kt");

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirDeclarationsResolveTransformer.kt

@@ -143,7 +143,7 @@ open class FirDeclarationsResolveTransformer(transformer: FirBodyResolveTransfor
                                 storeVariableReturnType(property)
                             }
                             withLocalScopeCleanup {
-                                if (property.receiverTypeRef == null) {
+                                if (property.receiverTypeRef == null && property.returnTypeRef !is FirImplicitTypeRef) {
                                     addLocalScope(FirLocalScope().storeBackingField(property))
                                 }
                                 property.transformAccessors()

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/explicitGetterType.fir.kt

@@ -5,7 +5,7 @@ val z get(): List<Int> {
     return bar()
 }
 
-val u get(): String = field
+val u get(): String = <!UNRESOLVED_REFERENCE!>field<!>
 
 fun <E> foo(): E = null!!
 fun <E> bar(): List<E> = null!!

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/recursiveGetter.fir.kt

@@ -13,7 +13,7 @@ class A {
     val z1 get() = <!INAPPLICABLE_CANDIDATE!>id<!>(z1)
     val z2 get() = <!INAPPLICABLE_CANDIDATE!>l<!>(z2)
 
-    val u get() = field
+    val u get() = <!UNRESOLVED_REFERENCE!>field<!>
 }
 
 fun <E> id(x: E) = x

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/unsupportedInferenceFromGetters.fir.kt

@@ -21,7 +21,7 @@ val z2 get(): List<Int> {
     return bar()
 }
 
-val u get(): String = field
+val u get(): String = <!UNRESOLVED_REFERENCE!>field<!>
 
 // members.kt
 class A {