[cls] write contracts information to cls stubs

^ KTIJ-24665
this information would be used to create resolved FirElements from stubs,
so no ProtoBuf would be kept in memory

analysis/decompiled/decompiler-to-stubs/src/org/jetbrains/kotlin/analysis/decompiler/stub/CallableClsStubBuilder.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.resolve.DataClassResolver
 import org.jetbrains.kotlin.serialization.deserialization.AnnotatedCallableKind
 import org.jetbrains.kotlin.serialization.deserialization.ProtoContainer
 import org.jetbrains.kotlin.serialization.deserialization.getName
+import org.jetbrains.kotlin.utils.addToStdlib.runIf
 
 fun createPackageDeclarationsStubs(
     parentStub: StubElement<out PsiElement>,
@@ -173,6 +174,7 @@ private class FunctionClsStubBuilder(
         // Note that arguments passed to stubs here and elsewhere are based on what stabs would be generated based on decompiled code
         // As functions are never decompiled to fun f() = 1 form, hasBlockBody is always true
         // This info is anyway irrelevant for the purposes these stubs are used
+        val hasContract = functionProto.hasContract()
         return KotlinFunctionStubImpl(
             parent,
             callableName.ref(),
@@ -182,7 +184,10 @@ private class FunctionClsStubBuilder(
             hasBlockBody = true,
             hasBody = Flags.MODALITY.get(functionProto.flags) != Modality.ABSTRACT,
             hasTypeParameterListBeforeFunctionName = functionProto.typeParameterList.isNotEmpty(),
-            mayHaveContract = functionProto.hasContract()
+            mayHaveContract = hasContract,
+            runIf(hasContract) {
+                ClsContractBuilder(c, typeStubBuilder).loadContract(functionProto)
+            }
         )
     }
 }

analysis/decompiled/decompiler-to-stubs/src/org/jetbrains/kotlin/analysis/decompiler/stub/ClsContractBuilder.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.analysis.decompiler.stub
+
+import org.jetbrains.kotlin.contracts.description.KtBooleanValueParameterReference
+import org.jetbrains.kotlin.contracts.description.KtConstantReference
+import org.jetbrains.kotlin.contracts.description.KtEffectDeclaration
+import org.jetbrains.kotlin.contracts.description.KtValueParameterReference
+import org.jetbrains.kotlin.metadata.ProtoBuf
+import org.jetbrains.kotlin.metadata.deserialization.isInstanceType
+import org.jetbrains.kotlin.name.StandardClassIds
+import org.jetbrains.kotlin.psi.stubs.impl.*
+import org.jetbrains.kotlin.psi.stubs.impl.KotlinContractEffectType.Companion.IGNORE_REFERENCE_PARAMETER_NAME
+import org.jetbrains.kotlin.serialization.deserialization.ProtoBufContractDeserializer
+import org.jetbrains.kotlin.serialization.deserialization.getClassId
+
+class ClsContractBuilder(private val c: ClsStubBuilderContext, private val typeStubBuilder: TypeClsStubBuilder) :
+    ProtoBufContractDeserializer<KotlinTypeBean, Nothing?, ProtoBuf.Function>() {
+
+    fun loadContract(proto: ProtoBuf.Function): List<KtEffectDeclaration<KotlinTypeBean, Nothing?>>? {
+        return proto.contract.effectList.map { loadPossiblyConditionalEffect(it, proto) ?: return null }
+    }
+
+    override fun extractVariable(valueParameterIndex: Int, owner: ProtoBuf.Function): KtValueParameterReference<KotlinTypeBean, Nothing?> {
+        val type = if (valueParameterIndex < 0) {
+            owner.receiverType
+        } else owner.valueParameterList[valueParameterIndex].type
+        return if (type.hasClassName() && c.nameResolver.getClassId(type.className) == StandardClassIds.Boolean) {
+            KtBooleanValueParameterReference(valueParameterIndex, name = IGNORE_REFERENCE_PARAMETER_NAME)
+        } else KtValueParameterReference(valueParameterIndex, name = IGNORE_REFERENCE_PARAMETER_NAME)
+    }
+
+    override fun extractType(proto: ProtoBuf.Expression): KotlinTypeBean? {
+        return typeStubBuilder.createKotlinTypeBean(proto.isInstanceType(c.typeTable))
+    }
+
+    override fun loadConstant(value: ProtoBuf.Expression.ConstantValue): KtConstantReference<KotlinTypeBean, Nothing?> {
+        return when (value) {
+            ProtoBuf.Expression.ConstantValue.TRUE -> KotlinContractConstantValues.TRUE
+            ProtoBuf.Expression.ConstantValue.FALSE -> KotlinContractConstantValues.FALSE
+            ProtoBuf.Expression.ConstantValue.NULL -> KotlinContractConstantValues.NULL
+        }
+    }
+
+    override fun getNotNull(): KtConstantReference<KotlinTypeBean, Nothing?> {
+        return KotlinContractConstantValues.NOT_NULL
+    }
+
+    override fun getWildcard(): KtConstantReference<KotlinTypeBean, Nothing?> {
+        return KotlinContractConstantValues.WILDCARD
+    }
+}

analysis/decompiled/decompiler-to-stubs/src/org/jetbrains/kotlin/analysis/decompiler/stub/TypeClsStubBuilder.kt

@@ -150,7 +150,7 @@ class TypeClsStubBuilder(private val c: ClsStubBuilderContext) {
         }
     }
 
-    private fun createKotlinTypeBean(
+    fun createKotlinTypeBean(
         type: Type?
     ): KotlinTypeBean? {
         if (type == null) return null