Kotlin: don't emit synthetic parameter names

The QL library already expects these to be missing in some cases and generates its own names when they are absent. Writing synthetic names to the database can produce inconsistencies if the true name is seen later.

Author: smowton

java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt

@@ -507,6 +507,9 @@ open class KotlinFileExtractor(
         return FieldResult(instanceId, instanceName)
     }
 
+    @OptIn(ObsoleteDescriptorBasedAPI::class)
+    private fun hasSynthesizedParameterNames(f: IrFunction) = f.descriptor.hasSynthesizedParameterNames()
+
     private fun extractValueParameter(vp: IrValueParameter, parent: Label<out DbCallable>, idx: Int, typeSubstitution: TypeSubstitution?, parentSourceDeclaration: Label<out DbCallable>, classTypeArgsIncludingOuterClasses: List<IrTypeArgument>?, extractTypeAccess: Boolean, locOverride: Label<DbLocation>? = null): TypeResults {
         with("value parameter", vp) {
             val location = locOverride ?: getLocation(vp, classTypeArgsIncludingOuterClasses)
@@ -523,16 +526,19 @@ open class KotlinFileExtractor(
             if (extractTypeAccess) {
                 extractTypeAccessRecursive(substitutedType, location, id, -1)
             }
-            return extractValueParameter(id, substitutedType, vp.name.asString(), location, parent, idx, useValueParameter(vp, parentSourceDeclaration), vp.isVararg)
+            val syntheticParameterNames = (vp.parent as? IrFunction)?.let { hasSynthesizedParameterNames(it) } ?: true
+            return extractValueParameter(id, substitutedType, vp.name.asString(), location, parent, idx, useValueParameter(vp, parentSourceDeclaration), vp.isVararg, syntheticParameterNames)
         }
     }
 
-    private fun extractValueParameter(id: Label<out DbParam>, t: IrType, name: String, locId: Label<DbLocation>, parent: Label<out DbCallable>, idx: Int, paramSourceDeclaration: Label<out DbParam>, isVararg: Boolean): TypeResults {
+    private fun extractValueParameter(id: Label<out DbParam>, t: IrType, name: String, locId: Label<DbLocation>, parent: Label<out DbCallable>, idx: Int, paramSourceDeclaration: Label<out DbParam>, isVararg: Boolean, syntheticParameterNames: Boolean): TypeResults {
         val type = useType(t)
         tw.writeParams(id, type.javaResult.id, idx, parent, paramSourceDeclaration)
         tw.writeParamsKotlinType(id, type.kotlinResult.id)
         tw.writeHasLocation(id, locId)
-        tw.writeParamName(id, name)
+        if (!syntheticParameterNames) {
+            tw.writeParamName(id, name)
+        }
         if (isVararg) {
             tw.writeIsVarargsParam(id)
         }
@@ -2952,7 +2958,7 @@ open class KotlinFileExtractor(
             stmtIdx: Int
         ) {
             val paramId = tw.getFreshIdLabel<DbParam>()
-            val paramTypeRes = extractValueParameter(paramId, paramType, paramName, locId, ids.constructor, paramIdx, paramId, false)
+            val paramTypeRes = extractValueParameter(paramId, paramType, paramName, locId, ids.constructor, paramIdx, paramId, isVararg = false, syntheticParameterNames = false)
 
             val assignmentStmtId = tw.getFreshIdLabel<DbExprstmt>()
             tw.writeStmts_exprstmt(assignmentStmtId, ids.constructorBlock, stmtIdx, ids.constructor)
@@ -3588,7 +3594,7 @@ open class KotlinFileExtractor(
 
         val parameters = parameterTypes.mapIndexed { idx, p ->
             val paramId = tw.getFreshIdLabel<DbParam>()
-            val paramType = extractValueParameter(paramId, p, "a$idx", locId, methodId, idx, paramId, false)
+            val paramType = extractValueParameter(paramId, p, "a$idx", locId, methodId, idx, paramId, isVararg = false, syntheticParameterNames = false)
 
             Pair(paramId, paramType)
         }