Fix binding method without body inside of interface wrongly assumed t…

…o not be abstract in BindsMethodValidator

compiler-utils/src/main/java/com/squareup/anvil/compiler/internal/reference/ClassReference.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.Modality.ABSTRACT
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
+import org.jetbrains.kotlin.descriptors.findClassAcrossModuleDependencies
 import org.jetbrains.kotlin.lexer.KtTokens.ABSTRACT_KEYWORD
 import org.jetbrains.kotlin.lexer.KtTokens.INTERNAL_KEYWORD
 import org.jetbrains.kotlin.lexer.KtTokens.PRIVATE_KEYWORD
@@ -40,6 +41,9 @@ import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.parents
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.resolve.scopes.getDescriptorsFiltered
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.TypeUtils
+import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import kotlin.LazyThreadSafetyMode.NONE
 
 /**
@@ -85,6 +89,8 @@ public sealed class ClassReference : Comparable<ClassReference>, AnnotatedRefere
  */
  public abstract fun enclosingClassesWithSelf(): List<ClassReference>
 
+ internal abstract fun getDescriptor(): ClassDescriptor
+
  public fun enclosingClass(): ClassReference? {
  val classes = enclosingClassesWithSelf()
  val index = classes.indexOf(this)
@@ -220,6 +226,14 @@ public sealed class ClassReference : Comparable<ClassReference>, AnnotatedRefere
 
  override fun enclosingClassesWithSelf(): List<Psi> = enclosingClassesWithSelf
 
+ override fun getDescriptor(): ClassDescriptor {
+ return module.findClassAcrossModuleDependencies(this.classId)
+ ?: throw AnvilCompilationException(
+ element = clazz,
+ message = "Couldn't find descriptor for class $fqName.",
+ )
+ }
+
  @Suppress("UNCHECKED_CAST")
  override fun innerClasses(): List<Psi> =
  super.innerClasses() as List<Psi>
@@ -323,6 +337,10 @@ public sealed class ClassReference : Comparable<ClassReference>, AnnotatedRefere
 
  override fun enclosingClassesWithSelf(): List<Descriptor> = enclosingClassesWithSelf
 
+ override fun getDescriptor(): ClassDescriptor {
+ return clazz
+ }
+
  @Suppress("UNCHECKED_CAST")
  override fun innerClasses(): List<Descriptor> =
  super.innerClasses() as List<Descriptor>
@@ -433,9 +451,28 @@ public fun AnvilCompilationExceptionClassReference(
  message = message,
  cause = cause,
  )
+
  is Descriptor -> AnvilCompilationException(
  classDescriptor = classReference.clazz,
  message = message,
  cause = cause,
  )
 }
+
+fun TypeReference.isAssignableTo(
+ other: TypeReference
+): Boolean {
+ return KotlinTypeChecker.DEFAULT.isSubtypeOf(
+ getFullKotlinType(),
+ other.getFullKotlinType(),
+ )
+}
+
+fun TypeReference.getFullKotlinType(): KotlinType {
+ val descriptor = asClassReference().getDescriptor()
+ val typeArguments = this.unwrappedTypes.map { it.getFullKotlinType() }
+ return TypeUtils.substituteParameters(
+ descriptor,
+ typeArguments,
+ )
+}

compiler/src/main/java/com/squareup/anvil/compiler/codegen/dagger/BindsMethodValidator.kt

@@ -9,7 +9,6 @@ import com.google.devtools.ksp.symbol.KSClassDeclaration
 import com.google.devtools.ksp.symbol.KSFunctionDeclaration
 import com.google.devtools.ksp.symbol.KSType
 import com.google.devtools.ksp.symbol.KSTypeReference
-import com.google.devtools.ksp.symbol.Modifier
 import com.squareup.anvil.compiler.api.AnvilApplicabilityChecker
 import com.squareup.anvil.compiler.api.AnvilContext
 import com.squareup.anvil.compiler.api.CodeGenerator
@@ -59,7 +58,7 @@ internal object BindsMethodValidator : AnvilApplicabilityChecker {
  internal fun bindsParameterMustBeAssignable(
  paramSuperTypeNames: List<String>,
  returnTypeName: String,
- parameterName: String?,
+ parameterType: String?,
  ): String {
  val superTypesMessage = if (paramSuperTypeNames.isEmpty()) {
  "has no supertypes."
@@ -69,7 +68,7 @@ internal object BindsMethodValidator : AnvilApplicabilityChecker {
 
  return "@Binds methods' parameter type must be assignable to the return type. " +
  "Expected binding of type $returnTypeName but impl parameter of type " +
- "$parameterName $superTypesMessage"
+ "$parameterType $superTypesMessage"
  }
  }
 
@@ -102,7 +101,7 @@ internal object BindsMethodValidator : AnvilApplicabilityChecker {
  private val resolver: Resolver
  ) {
  internal fun validateBindsFunction(function: KSFunctionDeclaration) {
- if (!function.modifiers.contains(Modifier.ABSTRACT)) {
+ if (!function.isAbstract) {
  throw KspAnvilException(
  message = Errors.BINDS_MUST_BE_ABSTRACT,
  node = function,
@@ -129,31 +128,32 @@ internal object BindsMethodValidator : AnvilApplicabilityChecker {
  node = function,
  )
 
+ val parameterSuperTypes = function.parameterSuperTypes()
+ val receiverSuperTypes = function.receiverSuperTypes()
  when (returnType) {
- in function.parameterSuperTypes() -> return
- in function.receiverSuperTypes() -> return
+ in parameterSuperTypes -> return
+ in receiverSuperTypes -> return
  }
 
  val returnTypeRef = returnType.declaration.simpleName.asString()
- val paramSuperTypes =
- function
- .parameterSuperTypes()
- .ifEmpty { function.receiverSuperTypes() }
+ val actualParameterSuperTypes =
+ parameterSuperTypes
+ .ifEmpty { receiverSuperTypes }
 
  val lastParameterType = function.parameters.lastOrNull()?.type
  val parameterRef = lastParameterType ?: function.extensionReceiver
  val param = parameterRef?.resolve()
 
- val paramSuperTypeNames =
- paramSuperTypes
+ val actualParameterSuperTypeNames =
+ actualParameterSuperTypes
  .map { it.declaration.simpleName.asString() }
  .toList()
 
  throw KspAnvilException(
  message = Errors.bindsParameterMustBeAssignable(
- paramSuperTypeNames = paramSuperTypeNames,
+ paramSuperTypeNames = actualParameterSuperTypeNames,
  returnTypeName = returnTypeRef,
- parameterName = param?.declaration?.simpleName?.getShortName(),
+ parameterType = param?.declaration?.simpleName?.getShortName(),
  ),
  node = function,
  )
@@ -232,7 +232,7 @@ internal object BindsMethodValidator : AnvilApplicabilityChecker {
 
  if (!function.parameterMatchesReturnType() && !function.receiverMatchesReturnType()) {
  val returnType = function.returnType().asClassReference().shortName
- val paramSuperTypes =
+ val actualParameterSuperTypes =
  function
  .parameterSuperTypes()
  .ifEmpty { function.receiverSuperTypes() }
@@ -241,9 +241,9 @@ internal object BindsMethodValidator : AnvilApplicabilityChecker {
 
  throw AnvilCompilationExceptionFunctionReference(
  message = Errors.bindsParameterMustBeAssignable(
- paramSuperTypeNames = paramSuperTypes.drop(1),
+ paramSuperTypeNames = actualParameterSuperTypes.drop(1),
  returnTypeName = returnType,
- parameterName = paramSuperTypes.first(),
+ parameterType = actualParameterSuperTypes.first(),
  ),
  functionReference = function,
  )

compiler/src/test/java/com/squareup/anvil/compiler/dagger/BindsMethodValidatorTest.kt

@@ -379,6 +379,30 @@ class BindsMethodValidatorTest(
  }
  }
 
+ @Test
+ fun `binding inside interface is valid`() {
+ compile(
+ """
+ package com.squareup.test
+
+ import dagger.Binds
+ import dagger.Module
+ import javax.inject.Inject
+
+ interface Foo : Bar
+ interface Bar
+
+ @Module
+ interface BarModule {
+ @Binds
+ fun bindsBar(foo: Foo): Bar
+ }
+ """,
+ ) {
+ assertThat(exitCode).isEqualTo(OK)
+ }
+ }
+
  private fun compile(
  @Language("kotlin") vararg sources: String,
  previousCompilationResult: JvmCompilationResult? = null,