FIR: Do not add "field" to accessor of a property with receiver

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

@@ -205,10 +205,6 @@ abstract class FirAbstractBodyResolveTransformer(phase: FirResolvePhase) : FirAb
             updateLastScope { storeVariable(variable) }
         }
 
-        fun storeBackingField(property: FirProperty) {
-            updateLastScope { storeBackingField(property) }
-        }
-
         override fun saveContextForAnonymousFunction(anonymousFunction: FirAnonymousFunction) {
             localContextForAnonymousFunctions[anonymousFunction.symbol] = FirLocalContext(localScopes, implicitReceiverStack.snapshot())
         }

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

@@ -114,7 +114,9 @@ class FirDeclarationsResolveTransformer(transformer: FirBodyResolveTransformer)
                                 storeVariableReturnType(property)
                             }
                             withLocalScopeCleanup {
-                                addLocalScope(FirLocalScope().storeBackingField(property))
+                                if (property.receiverTypeRef == null) {
+                                    addLocalScope(FirLocalScope().storeBackingField(property))
+                                }
                                 property.transformAccessors()
                             }
                         }

compiler/fir/resolve/testData/resolve/properties/noBackingFieldForExtension.kt

@@ -0,0 +1,11 @@
+interface B {
+    fun foo(): Int
+}
+
+class A {
+    val String.x: Int get() {
+        return field.foo()
+    }
+
+    val String.field: B get() = TODO()
+}

compiler/fir/resolve/testData/resolve/properties/noBackingFieldForExtension.txt

@@ -0,0 +1,21 @@
+FILE: noBackingFieldForExtension.kt
+    public abstract interface B : R|kotlin/Any| {
+        public abstract fun foo(): R|kotlin/Int|
+
+    }
+    public final class A : R|kotlin/Any| {
+        public constructor(): R|A| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final val R|kotlin/String|.x: R|kotlin/Int|
+            public get(): R|kotlin/Int| {
+                ^ (this@R|/A|, this@R|/A.x|).R|/A.field|.R|/B.foo|()
+            }
+
+        public final val R|kotlin/String|.field: R|B|
+            public get(): R|B| {
+                ^ R|kotlin/TODO|()
+            }
+
+    }

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsTestGenerated.java

@@ -1463,6 +1463,24 @@ public class FirDiagnosticsTestGenerated extends AbstractFirDiagnosticsTest {
         }
     }
 
+    @TestMetadata("compiler/fir/resolve/testData/resolve/properties")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class Properties extends AbstractFirDiagnosticsTest {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInProperties() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/fir/resolve/testData/resolve/properties"), Pattern.compile("^([^.]+)\\.kt$"), null, true);
+        }
+
+        @TestMetadata("noBackingFieldForExtension.kt")
+        public void testNoBackingFieldForExtension() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/properties/noBackingFieldForExtension.kt");
+        }
+    }
+
     @TestMetadata("compiler/fir/resolve/testData/resolve/references")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsWithLightTreeTestGenerated.java

@@ -1463,6 +1463,24 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
         }
     }
 
+    @TestMetadata("compiler/fir/resolve/testData/resolve/properties")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class Properties extends AbstractFirDiagnosticsWithLightTreeTest {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInProperties() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/fir/resolve/testData/resolve/properties"), Pattern.compile("^([^.]+)\\.kt$"), null, true);
+        }
+
+        @TestMetadata("noBackingFieldForExtension.kt")
+        public void testNoBackingFieldForExtension() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/properties/noBackingFieldForExtension.kt");
+        }
+    }
+
     @TestMetadata("compiler/fir/resolve/testData/resolve/references")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)

compiler/testData/diagnostics/tests/backingField/ExtensionProperty.fir.kt

@@ -8,10 +8,10 @@ val String.foo: Int
 
 val String.bar: Int = 13
     // Error
-    get() = field
+    get() = <!UNRESOLVED_REFERENCE!>field<!>
 
 class My {
     val String.x: Int = 7
         // Error
-        get() = field
+        get() = <!UNRESOLVED_REFERENCE!>field<!>
 }