Always consider container's experimentality in ExperimentalUsageChecker

This results in more diagnostics usually, but allows library authors to
avoid annotating everything in each experimental class with the marker
(only the class needs to be annotated now)

 #KT-22759

compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExperimentalUsageChecker.kt

@@ -142,9 +142,7 @@ class ExperimentalUsageChecker(project: Project) : CallChecker {
 
             val container = containingDeclaration
             if (container is ClassDescriptor && this !is ConstructorDescriptor) {
-                for (annotation in container.annotations) {
-                    result.addIfNotNull(annotation.annotationClass?.loadExperimentalityForMarkerAnnotation())
-                }
+                result.addAll(container.loadExperimentalities(moduleAnnotationsResolver))
             }
 
             for (moduleAnnotationClassId in moduleAnnotationsResolver.getAnnotationsOnContainingModule(this)) {

compiler/testData/diagnostics/testsWithStdLib/experimental/deeplyNestedClass.kt

@@ -0,0 +1,61 @@
+// !API_VERSION: 1.3
+// MODULE: api
+// FILE: api.kt
+
+package api
+
+@Experimental(Experimental.Level.WARNING, [Experimental.Impact.COMPILATION])
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
+annotation class ExperimentalAPI
+
+@ExperimentalAPI
+class C {
+    class D {
+        class E {
+            class F
+        }
+    }
+}
+
+// MODULE: usage1(api)
+// FILE: usage-propagate.kt
+
+package usage1
+
+import api.*
+
+@ExperimentalAPI
+fun use1() {
+    C.D.E.F()
+}
+
+@ExperimentalAPI
+fun use2(f: C.D.E.F) = f.hashCode()
+
+// MODULE: usage2(api)
+// FILE: usage-use.kt
+
+package usage2
+
+import api.*
+
+@UseExperimental(ExperimentalAPI::class)
+fun use1() {
+    C.D.E.F()
+}
+
+@UseExperimental(ExperimentalAPI::class)
+fun use2(f: <!EXPERIMENTAL_API_USAGE!>C<!>.<!EXPERIMENTAL_API_USAGE!>D<!>.<!EXPERIMENTAL_API_USAGE!>E<!>.<!EXPERIMENTAL_API_USAGE!>F<!>) = f.hashCode()
+
+// MODULE: usage3(api)
+// FILE: usage-none.kt
+
+package usage3
+
+import api.*
+
+fun use1() {
+    <!EXPERIMENTAL_API_USAGE!>C<!>.<!EXPERIMENTAL_API_USAGE!>D<!>.<!EXPERIMENTAL_API_USAGE!>E<!>.<!EXPERIMENTAL_API_USAGE!>F<!>()
+}
+
+fun use2(f: <!EXPERIMENTAL_API_USAGE!>C<!>.<!EXPERIMENTAL_API_USAGE!>D<!>.<!EXPERIMENTAL_API_USAGE!>E<!>.<!EXPERIMENTAL_API_USAGE!>F<!>) = f.<!EXPERIMENTAL_API_USAGE!>hashCode<!>()

compiler/testData/diagnostics/testsWithStdLib/experimental/deeplyNestedClass.txt

@@ -0,0 +1,76 @@
+// -- Module: <api> --
+package
+
+package api {
+
+    @api.ExperimentalAPI public final class C {
+        public constructor C()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        public final class D {
+            public constructor D()
+            public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+            public final class E {
+                public constructor E()
+                public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+                public final class F {
+                    public constructor F()
+                    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+                    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+                    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+                }
+            }
+        }
+    }
+
+    @kotlin.Experimental(changesMayBreak = {Impact.COMPILATION}, level = Level.WARNING) @kotlin.annotation.Target(allowedTargets = {AnnotationTarget.CLASS, AnnotationTarget.FUNCTION}) public final annotation class ExperimentalAPI : kotlin.Annotation {
+        public constructor ExperimentalAPI()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+
+// -- Module: <usage1> --
+package
+
+package api {
+}
+
+package usage1 {
+    @api.ExperimentalAPI public fun use1(): kotlin.Unit
+    @api.ExperimentalAPI public fun use2(/*0*/ f: api.C.D.E.F): kotlin.Int
+}
+
+
+// -- Module: <usage2> --
+package
+
+package api {
+}
+
+package usage2 {
+    @kotlin.UseExperimental(markerClass = {api.ExperimentalAPI::class}) public fun use1(): kotlin.Unit
+    @kotlin.UseExperimental(markerClass = {api.ExperimentalAPI::class}) public fun use2(/*0*/ f: api.C.D.E.F): kotlin.Int
+}
+
+
+// -- Module: <usage3> --
+package
+
+package api {
+}
+
+package usage3 {
+    public fun use1(): kotlin.Unit
+    public fun use2(/*0*/ f: api.C.D.E.F): kotlin.Int
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java

@@ -1839,6 +1839,12 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
             doTest(fileName);
         }
 
+        @TestMetadata("deeplyNestedClass.kt")
+        public void testDeeplyNestedClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithStdLib/experimental/deeplyNestedClass.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("errors.kt")
         public void testErrors() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithStdLib/experimental/errors.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java

@@ -1839,6 +1839,12 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
             doTest(fileName);
         }
 
+        @TestMetadata("deeplyNestedClass.kt")
+        public void testDeeplyNestedClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithStdLib/experimental/deeplyNestedClass.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("errors.kt")
         public void testErrors() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/testsWithStdLib/experimental/errors.kt");