remove nullable marker on KSValueParameter.type, add logic to retrieve type information from property for property setters' value parameter

Author: neetopia

api/src/main/kotlin/com/google/devtools/ksp/symbol/KSValueParameter.kt

@@ -30,8 +30,7 @@ interface KSValueParameter : KSAnnotated {
     /**
      *  The reference to the type of the parameter.
      */
-    // TODO: a setter doesn't have a type; However, it can be learned from the corresponding property declaration.
-    val type: KSTypeReference?
+    val type: KSTypeReference
 
     /**
      * True if it is a vararg.

compiler-plugin/src/main/kotlin/com/google/devtools/ksp/processor/ParameterTypeProcessor.kt

@@ -0,0 +1,25 @@
+package com.google.devtools.ksp.processor
+
+import com.google.devtools.ksp.processing.Resolver
+import com.google.devtools.ksp.symbol.KSNode
+import com.google.devtools.ksp.symbol.KSValueParameter
+import com.google.devtools.ksp.visitor.KSTopDownVisitor
+
+class ParameterTypeProcessor : AbstractTestProcessor() {
+    val result = mutableListOf<String>()
+
+    override fun toResult(): List<String> {
+        return result
+    }
+
+    override fun process(resolver: Resolver) {
+        resolver.getAllFiles().map { it.accept(object : KSTopDownVisitor<Unit, Unit>() {
+            override fun defaultHandler(node: KSNode, data: Unit) {
+            }
+
+            override fun visitValueParameter(valueParameter: KSValueParameter, data: Unit) {
+                result.add(valueParameter.type.resolve().toString())
+            }
+        }, Unit) }
+    }
+}

compiler-plugin/src/main/kotlin/com/google/devtools/ksp/symbol/impl/kotlin/KSValueParameterImpl.kt

@@ -20,10 +20,13 @@ package com.google.devtools.ksp.symbol.impl.kotlin
 
 import com.google.devtools.ksp.symbol.*
 import com.google.devtools.ksp.symbol.impl.KSObjectCache
+import com.google.devtools.ksp.symbol.impl.findParentDeclaration
+import com.google.devtools.ksp.symbol.impl.synthetic.KSTypeReferenceSyntheticImpl
 import com.google.devtools.ksp.symbol.impl.toLocation
 import org.jetbrains.kotlin.lexer.KtTokens.CROSSINLINE_KEYWORD
 import org.jetbrains.kotlin.lexer.KtTokens.NOINLINE_KEYWORD
 import org.jetbrains.kotlin.psi.KtParameter
+import org.jetbrains.kotlin.psi.KtProperty
 
 class KSValueParameterImpl private constructor(val ktParameter: KtParameter) : KSValueParameter {
     companion object : KSObjectCache<KtParameter, KSValueParameterImpl>() {
@@ -58,8 +61,8 @@ class KSValueParameterImpl private constructor(val ktParameter: KtParameter) : K
         }
     }
 
-    override val type: KSTypeReference? by lazy {
-        ktParameter.typeReference?.let { KSTypeReferenceImpl.getCached(it) }
+    override val type: KSTypeReference by lazy {
+        ktParameter.typeReference?.let { KSTypeReferenceImpl.getCached(it) } ?: findPropertyForAccessor()?.type ?: KSTypeReferenceSyntheticImpl.getCached(KSErrorType)
     }
 
     override val hasDefault: Boolean = ktParameter.hasDefaultValue()
@@ -71,4 +74,8 @@ class KSValueParameterImpl private constructor(val ktParameter: KtParameter) : K
     override fun toString(): String {
         return name?.asString() ?: "_"
     }
+
+    private fun findPropertyForAccessor(): KSPropertyDeclaration? {
+        return (ktParameter.parent?.parent?.parent as? KtProperty)?.let { KSPropertyDeclarationImpl.getCached(it) }
+    }
 }

compiler-plugin/src/test/java/com/google/devtools/ksp/test/KotlinKSPTestGenerated.java

@@ -137,6 +137,11 @@ public void testMultipleModules() throws Exception {
         runTest("testData/api/multipleModules.kt");
     }
 
+    @TestMetadata("parameterTypes.kt")
+    public void testParameterTypes() throws Exception {
+        runTest("testData/api/parameterTypes.kt");
+    }
+
     @TestMetadata("platformDeclaration.kt")
     public void testPlatformDeclaration() throws Exception {
         runTest("testData/api/platformDeclaration.kt");

compiler-plugin/testData/api/parameterTypes.kt

@@ -0,0 +1,20 @@
+// TEST PROCESSOR: ParameterTypeProcessor
+// EXPECTED:
+// <ERROR TYPE>
+// Int
+// Int
+// <ERROR TYPE>
+// <ERROR TYPE>
+// END
+
+class Foo {
+    var a: ErrorType
+    set(value) {
+        a = value
+    }
+    var a:Int
+    get() = a
+    set(value) { a = value }
+
+    fun foo(a: Int, b: NonExist, c)
+}