Fix complex alias handling in KsTypes (#1929)

Author: ZacSweers

docs/changelog.md

@@ -5,6 +5,7 @@ Change Log
 
 * **Fix**: Don't expand typealiases of function types to `LambdaTypeName`s in `KSTypeReference.toTypeName()`.
 * **Fix**: Small double and float values were set to 0.0 in %L translation (#1919)
+* **Fix**: Fix typealias type argument resolution in KSP2.
 * **Enhancement**: Make enum entry references in `KSAnnotation.toAnnotationSpec()` and `KSClassDeclaration.toClassName()` more robust.
 * Migrate `kotlinpoet-metadata` to stable `org.jetbrains.kotlin:kotlin-metadata-jvm` artifact for Metadata parsing.
 * Promote `kotlinpoet-metadata` out of preview to stable.

interop/ksp/src/main/kotlin/com/squareup/kotlinpoet/ksp/KsTypes.kt

@@ -199,6 +199,6 @@ public fun KSTypeReference.toTypeName(
  returnType = elem.returnType.toTypeName(typeParamResolver),
  ).copy(nullable = type.isMarkedNullable, suspending = type.isSuspendFunctionType)
  } else {
- type.toTypeName(typeParamResolver, element?.typeArguments.orEmpty())
+ type.toTypeName(typeParamResolver, type.arguments)
  }
 }

interop/ksp/test-processor/src/test/kotlin/com/squareup/kotlinpoet/ksp/test/processor/TestProcessorTest.kt

@@ -911,6 +911,49 @@ class TestProcessorTest(private val useKsp2: Boolean) {
  )
  }
 
+ @Test
+ fun complexAliasing() {
+ val compilation = prepareCompilation(
+ kotlin(
+ "Example.kt",
+ """
+ package test
+
+ import javax.inject.Provider
+ import com.squareup.kotlinpoet.ksp.test.processor.ExampleAnnotation
+
+ typealias DaggerProvider<T> = @JvmSuppressWildcards Provider<T>
+ interface SelectOptions
+ interface SelectHandler<T>
+
+ @ExampleAnnotation
+ class Example(
+ private val handlers: Map<Class<out SelectOptions>, DaggerProvider<SelectHandler<*>>>,
+ )
+ """,
+ ),
+ )
+
+ val result = compilation.compile()
+ assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+ val generatedFileText = File(compilation.kspSourcesDir, "kotlin/test/TestExample.kt")
+ .readText()
+
+ assertThat(generatedFileText).isEqualTo(
+ """
+ package test
+
+ import java.lang.Class
+ import kotlin.collections.Map
+
+ public class TestExample {
+ private val handlers: Map<Class<out SelectOptions>, DaggerProvider<SelectHandler<*>>> = TODO()
+ }
+
+ """.trimIndent(),
+ )
+ }
+
  private fun prepareCompilation(vararg sourceFiles: SourceFile): KotlinCompilation {
  return KotlinCompilation()
  .apply {