FIR: Do not build synthetic property named with first capital character

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -41760,6 +41760,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/syntheticExtensions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @Test
+        @TestMetadata("firstCapitalizedProperty.kt")
+        public void testFirstCapitalizedProperty() throws Exception {
+            runTest("compiler/testData/codegen/box/syntheticExtensions/firstCapitalizedProperty.kt");
+        }
+
         @Test
         @TestMetadata("fromTwoBases.kt")
         public void testFromTwoBases() throws Exception {

compiler/fir/jvm/src/org/jetbrains/kotlin/fir/resolve/FirJavaSyntheticNamesProvider.kt

@@ -28,6 +28,8 @@ object FirJavaSyntheticNamesProvider : FirSyntheticNamesProvider() {
         if (name.isSpecial) return emptyList()
         val identifier = name.identifier
         if (identifier.isEmpty()) return emptyList()
+        val firstChar = identifier[0]
+        if (!firstChar.isJavaIdentifierStart() || firstChar in 'A'..'Z') return emptyList()
         val result = ArrayList<Name>(3)
         val standardName = Name.identifier(GETTER_PREFIX + identifier.capitalizeAsciiOnly())
         val length = identifier.length

compiler/testData/codegen/box/syntheticExtensions/firstCapitalizedProperty.kt

@@ -0,0 +1,29 @@
+// TARGET_BACKEND: JVM
+
+// MODULE: lib
+
+// FILE: test/UI.java
+package test;
+public class UI {
+    public static String foo() {
+        return "OK";
+    }
+}
+
+// FILE: Parent.java
+public class Parent {
+    public String getUI() { return "fail"; }
+}
+
+// MODULE: main(lib)
+// FILE: main.kt
+
+import test.UI;
+
+class Derived : Parent() {
+    fun bar(): String = UI.foo()
+}
+
+fun box(): String {
+    return Derived().bar()
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java

@@ -41586,6 +41586,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/syntheticExtensions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM, true);
         }
 
+        @Test
+        @TestMetadata("firstCapitalizedProperty.kt")
+        public void testFirstCapitalizedProperty() throws Exception {
+            runTest("compiler/testData/codegen/box/syntheticExtensions/firstCapitalizedProperty.kt");
+        }
+
         @Test
         @TestMetadata("fromTwoBases.kt")
         public void testFromTwoBases() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -41760,6 +41760,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/syntheticExtensions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
         }
 
+        @Test
+        @TestMetadata("firstCapitalizedProperty.kt")
+        public void testFirstCapitalizedProperty() throws Exception {
+            runTest("compiler/testData/codegen/box/syntheticExtensions/firstCapitalizedProperty.kt");
+        }
+
         @Test
         @TestMetadata("fromTwoBases.kt")
         public void testFromTwoBases() throws Exception {

compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -33454,6 +33454,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/syntheticExtensions"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM, true);
         }
 
+        @TestMetadata("firstCapitalizedProperty.kt")
+        public void testFirstCapitalizedProperty() throws Exception {
+            runTest("compiler/testData/codegen/box/syntheticExtensions/firstCapitalizedProperty.kt");
+        }
+
         @TestMetadata("fromTwoBases.kt")
         public void testFromTwoBases() throws Exception {
             runTest("compiler/testData/codegen/box/syntheticExtensions/fromTwoBases.kt");