[Stubs] Fix stub inconsistency on unnamed setter parameters

If an unused setter parameter was replaced with an underscore ('_'),
it had a special name in the stub ('<anonymous parameter 0>'). The text
version of the stub inserted it as is, leading to an extra
'PsiErrorElement'.

^KTIJ-28194 Fixed

analysis/decompiled/decompiler-to-psi/src/org/jetbrains/kotlin/analysis/decompiler/psi/text/buildDecompiledText.kt

@@ -7,10 +7,12 @@ package org.jetbrains.kotlin.analysis.decompiler.psi.text
 
 import org.jetbrains.kotlin.analysis.decompiler.stub.COMPILED_DEFAULT_INITIALIZER
 import org.jetbrains.kotlin.analysis.decompiler.stub.COMPILED_DEFAULT_PARAMETER_VALUE
+import org.jetbrains.kotlin.analysis.decompiler.stub.computeParameterName
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.contracts.description.ContractProviderKey
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.psi.psiUtil.quoteIfNeeded
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
@@ -128,11 +130,8 @@ fun buildDecompiledText(
                             builder.append(descriptorRenderer.renderAnnotation(annotation))
                             builder.append(" ")
                         }
-                        val paramName = when (val name = parameterDescriptor.name) {
-                            SpecialNames.IMPLICIT_SET_PARAMETER -> StandardNames.DEFAULT_VALUE_PARAMETER
-                            else -> name
-                        }
-                        builder.append(paramName.asString()).append(": ")
+                        val parameterName = computeParameterName(parameterDescriptor.name)
+                        builder.append(parameterName.asString()).append(": ")
                             .append(descriptorRenderer.renderType(parameterDescriptor.type))
                         builder.append(")")
                         builder.append(" {").append(DECOMPILED_CODE_COMMENT).append(" }")

analysis/decompiled/decompiler-to-psi/tests/org/jetbrains/kotlin/analysis/decompiler/psi/ByDecompiledPsiStubBuilderK2CompilerTestGenerated.java

@@ -311,4 +311,10 @@ public class ByDecompiledPsiStubBuilderK2CompilerTestGenerated extends AbstractB
     public void testTypes() throws Exception {
         runTest("analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/Types/");
     }
+
+    @Test
+    @TestMetadata("UnderscoreParameterName")
+    public void testUnderscoreParameterName() throws Exception {
+        runTest("analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/UnderscoreParameterName/");
+    }
 }

analysis/decompiled/decompiler-to-psi/tests/org/jetbrains/kotlin/analysis/decompiler/psi/ByDecompiledPsiStubBuilderTestGenerated.java

@@ -311,4 +311,10 @@ public class ByDecompiledPsiStubBuilderTestGenerated extends AbstractByDecompile
     public void testTypes() throws Exception {
         runTest("analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/Types/");
     }
+
+    @Test
+    @TestMetadata("UnderscoreParameterName")
+    public void testUnderscoreParameterName() throws Exception {
+        runTest("analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/UnderscoreParameterName/");
+    }
 }