repro for #881

(cherry picked from commit 99518cb)

compiler-plugin/testData/api/typeAlias.kt

@@ -22,6 +22,13 @@
 // A = String
 // B = String
 // C = A = String
+// Int
+// List<Int>
+// ListOfInt = List<Int>
+// ListOfInt = List<Int>
+// ListOfInt_B = ListOfInt = List<Int>
+// ListOfInt_B = ListOfInt = List<Int>
+// ListOfInt_C = ListOfInt_B = ListOfInt = List<Int>
 // String
 // String
 // String
@@ -30,7 +37,13 @@
 typealias A = String
 typealias B = String
 typealias C = A
+typealias ListOfInt = List<Int>
+typealias ListOfInt_B = ListOfInt
+typealias ListOfInt_C = ListOfInt_B
 val a: A = ""
 val b: B = ""
 val c: C = ""
 val d: String = ""
+val listOfInt: ListOfInt = TODO()
+val listOfInt_B: ListOfInt_B = TODO()
+val listOfInt_C: ListOfInt_C = TODO()

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

@@ -33,25 +33,47 @@ open class TypeAliasProcessor : AbstractTestProcessor() {
         }
 
         val sortedTypes = types.sortedBy { it.declaration.simpleName.asString() }
-
+        val byFinalSignature = mutableMapOf<String, MutableList<KSType>>()
         for (i in sortedTypes) {
             val r = mutableListOf<String>()
             var a: KSType? = i
-            do {
-                r.add(a!!.declaration.simpleName.asString())
+            while(a != null) {
+                r.add(a.toSignature())
                 a = (a.declaration as? KSTypeAlias)?.type?.resolve()
-            } while (a != null)
+            }
             results.add(r.joinToString(" = "))
+            byFinalSignature.getOrPut(r.last()) {
+                mutableListOf()
+            }.add(i)
         }
-
-        for (i in types) {
-            for (j in types) {
-                assert(i == j)
+        byFinalSignature.forEach { (signature, sameTypeAliases) ->
+            for (i in sameTypeAliases) {
+                for (j in sameTypeAliases) {
+                    assert(i == j) {
+                        "$i and $j both map to $signature, equals should return true"
+                    }
+                }
+            }
+            assert(sameTypeAliases.map { it.hashCode() }.distinct().size == 1) {
+                "different hashcodes for members of $signature"
             }
         }
+
+
         return emptyList()
     }
 
+    private fun KSType.toSignature(): String = buildString {
+        append(declaration.simpleName.asString())
+        if (arguments.isNotEmpty()) {
+            append("<")
+            arguments.map {
+                it.type?.resolve()?.toSignature() ?: "<error>"
+            }.forEach(this::append)
+            append(">")
+        }
+    }
+
     override fun toResult(): List<String> {
         return results
     }