KSFunction: return type aliases if possible

AA expands types by default. Luckily, the abbreviations are handily
available. This change makes KSFunction behave the same as other parts
that return KSType in the API.

Author: ting-yuan

kotlin-analysis-api/src/main/kotlin/com/google/devtools/ksp/impl/symbol/kotlin/KSFunctionImpl.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.analysis.api.symbols.KaFunctionSymbol
 import org.jetbrains.kotlin.analysis.api.symbols.typeParameters
 import org.jetbrains.kotlin.analysis.api.types.KaSubstitutor
 import org.jetbrains.kotlin.analysis.api.types.KaType
+import org.jetbrains.kotlin.analysis.api.types.abbreviationOrSelf
 import org.jetbrains.kotlin.utils.addToStdlib.ifNotEmpty
 import java.util.*
 
@@ -35,11 +36,11 @@ class KSFunctionImpl @OptIn(KaExperimentalApi::class) constructor(
 ) : KSFunction {
 
     override val returnType: KSType? by lazy {
-        functionSignature.returnType.let { KSTypeImpl.getCached(it) }
+        functionSignature.returnType.abbreviationOrSelf.let { KSTypeImpl.getCached(it) }
     }
 
     override val parameterTypes: List<KSType?> by lazy {
-        functionSignature.valueParameters.map { it.returnType.let { KSTypeImpl.getCached(it) } }
+        functionSignature.valueParameters.map { it.returnType.abbreviationOrSelf.let { KSTypeImpl.getCached(it) } }
     }
 
     @OptIn(KaExperimentalApi::class)
@@ -69,7 +70,7 @@ class KSFunctionImpl @OptIn(KaExperimentalApi::class) constructor(
     }
 
     override val extensionReceiverType: KSType? by lazy {
-        functionSignature.receiverType?.let { KSTypeImpl.getCached(it) }
+        functionSignature.receiverType?.abbreviationOrSelf?.let { KSTypeImpl.getCached(it) }
     }
 
     override val isError: Boolean = false

kotlin-analysis-api/testData/typeAlias.kt

@@ -34,6 +34,8 @@
 // viewBinderProviders : Map<Class<BaseViewHolder>, @JvmSuppressWildcards Provider<BaseEmbedViewBinder>> = (expanded) Map<Class<BaseViewHolder>, Provider<ViewBinder<BaseViewHolder, SpaceshipEmbedModel>>>
 // nested1 : MyList<ListOfInt> = List<T> = (expanded) List<List<Int>>
 // nested2 : List<ListOfInt> = (expanded) List<List<Int>>
+// param w.o. asMemberOf: MyAlias<String> = Foo<Bar<T>, Baz<T>> = (expanded) Foo<Bar<String>, Baz<String>>
+// param with asMemberOf: MyAlias<String> = Foo<Bar<T>, Baz<T>> = (expanded) Foo<Bar<String>, Baz<String>>
 // END
 
 // MODULE: module1
@@ -78,3 +80,9 @@ typealias BaseEmbedViewBinder = ViewBinder<out BaseViewHolder, out SpaceshipEmbe
 val viewBinderProviders: Map<Class<out BaseViewHolder>, @JvmSuppressWildcards Provider<BaseEmbedViewBinder>> = TODO()
 val nested1: MyList<ListOfInt>
 val nested2: List<ListOfInt>
+
+class Subject(val param: MyAlias<String>)
+typealias MyAlias<T> = Foo<Bar<T>, Baz<T>>
+class Foo<T1, T2>
+class Bar<T>
+class Baz<T>

test-utils/src/main/kotlin/com/google/devtools/ksp/processor/TypeAliasProcessor.kt

@@ -17,6 +17,7 @@
 
 package com.google.devtools.ksp.processor
 
+import com.google.devtools.ksp.getConstructors
 import com.google.devtools.ksp.processing.Resolver
 import com.google.devtools.ksp.symbol.*
 
@@ -57,6 +58,19 @@ open class TypeAliasProcessor : AbstractTestProcessor() {
                 }
             }
         }
+
+        val subjectName = resolver.getKSNameFromString("Subject")
+        val subject = resolver.getClassDeclarationByName(subjectName)!!
+        val constructor = subject.getConstructors().single()
+        val type1 = constructor.parameters.single().type.resolve()
+        val type2 = constructor.asMemberOf(subject.asType(emptyList())).parameterTypes.single()!!
+        val type1Signatures = type1.typeAliasSignatures().joinToString(" = ")
+        val type2Signatures = type2.typeAliasSignatures().joinToString(" = ")
+        val type1Expanded = resolver.expandType(type1).toSignature()
+        val type2Expanded = resolver.expandType(type2).toSignature()
+
+        results.add("param w.o. asMemberOf: $type1Signatures = (expanded) $type1Expanded")
+        results.add("param with asMemberOf: $type2Signatures = (expanded) $type2Expanded")
         return emptyList()
     }
 

test-utils/testData/api/typeAlias.kt

@@ -34,6 +34,8 @@
 // viewBinderProviders : Map<Class<BaseViewHolder>, @JvmSuppressWildcards Provider<BaseEmbedViewBinder>> = (expanded) Map<Class<BaseViewHolder>, Provider<ViewBinder<BaseViewHolder, SpaceshipEmbedModel>>>
 // nested1 : MyList<ListOfInt> = List<T> = (expanded) List<List<Int>>
 // nested2 : List<ListOfInt> = (expanded) List<List<Int>>
+// param w.o. asMemberOf: MyAlias<String> = Foo<Bar<T>, Baz<T>> = (expanded) Foo<Bar<String>, Baz<String>>
+// param with asMemberOf: MyAlias<String> = Foo<Bar<T>, Baz<T>> = (expanded) Foo<Bar<String>, Baz<String>>
 // END
 
 // MODULE: module1
@@ -79,3 +81,9 @@ typealias BaseEmbedViewBinder = ViewBinder<out BaseViewHolder, out SpaceshipEmbe
 val viewBinderProviders: Map<Class<out BaseViewHolder>, @JvmSuppressWildcards Provider<BaseEmbedViewBinder>> = TODO()
 val nested1: MyList<ListOfInt>
 val nested2: List<ListOfInt>
+
+class Subject(val param: MyAlias<String>)
+typealias MyAlias<T> = Foo<Bar<T>, Baz<T>>
+class Foo<T1, T2>
+class Bar<T>
+class Baz<T>