Merge pull request #10313 from tamasvajk/kotlin-fix-vararg

Kotlin: Fix `vararg` extraction outside of method call

Author: tamasvajk

java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt

@@ -3105,7 +3105,13 @@ open class KotlinFileExtractor(
                     extractTypeOperatorCall(e, callable, exprParent.parent, exprParent.idx, exprParent.enclosingStmt)
                 }
                 is IrVararg -> {
-                    logger.errorElement("Unexpected IrVararg", e)
+                    if (e.elements.size != 1 || e.elements[0] !is IrSpreadElement) {
+                        logger.errorElement("Unexpected IrVararg", e)
+                        return
+                    }
+                    // There are lowered IR cases when the vararg expression is not within a call, such as
+                    // val temp0 = [*expr]
+                    extractExpression((e.elements[0] as IrSpreadElement).expression, callable, parent)
                 }
                 is IrGetObjectValue -> {
                     // For `object MyObject { ... }`, the .class has an

java/ql/test/kotlin/library-tests/vararg/args.expected

@@ -1,16 +1,19 @@
+diag
 varargsParams
 | test.kt:8:15:8:28 | xs | file://:0:0:0:0 | int[] |
 | test.kt:12:26:12:39 | xs | file://:0:0:0:0 | int[] |
 | test.kt:20:24:20:37 | xs | file://:0:0:0:0 | int[] |
 | test.kt:24:50:24:63 | xs | file://:0:0:0:0 | int[] |
 | test.kt:28:37:28:50 | xs | file://:0:0:0:0 | int[] |
+| test.kt:50:5:50:31 | s | file://:0:0:0:0 | String[] |
 explicitVarargsArguments
 | test.kt:12:50:12:51 | xs | test.kt:12:44:12:52 | this(...) |
 | test.kt:38:25:38:29 | array | test.kt:38:5:38:30 | funWithOnlyVarArgs(...) |
 | test.kt:39:41:39:45 | array | test.kt:39:5:39:46 | funWithArgsAndVarArgs(...) |
 | test.kt:40:34:40:38 | array | test.kt:40:5:40:49 | funWithMiddleVarArgs(...) |
 | test.kt:44:27:44:31 | array | test.kt:44:5:44:32 | new HasVarargConstructor(...) |
 | test.kt:45:34:45:38 | array | test.kt:45:5:45:39 | new HasVarargConstructor(...) |
+| test.kt:55:15:55:35 | tmp0_s | test.kt:55:13:55:43 | new X(...) |
 implicitVarargsArguments
 | intList.kt:3:21:3:22 | 10 | intList.kt:3:14:3:31 | listOf(...) | 0 |
 | intList.kt:3:25:3:26 | 11 | intList.kt:3:14:3:31 | listOf(...) | 1 |
@@ -78,3 +81,6 @@ implicitVarargsArguments
 | test.kt:44:5:44:32 | new HasVarargConstructor(...) | 0 | test.kt:44:27:44:31 | array |
 | test.kt:45:5:45:39 | new HasVarargConstructor(...) | 0 | test.kt:45:27:45:29 | foo |
 | test.kt:45:5:45:39 | new HasVarargConstructor(...) | 1 | test.kt:45:34:45:38 | array |
+| test.kt:55:13:55:43 | new X(...) | 0 | test.kt:55:42:55:42 | 1 |
+| test.kt:55:13:55:43 | new X(...) | 1 | test.kt:55:15:55:35 | tmp0_s |
+| test.kt:55:22:55:35 | toTypedArray(...) | 0 | test.kt:55:19:55:20 | sl |

java/ql/test/kotlin/library-tests/vararg/args.ql

@@ -1,4 +1,7 @@
 import java
+import semmle.code.java.Diagnostics
+
+query predicate diag(Diagnostic d) { d.getMessage() = "Unexpected IrVararg" }
 
 query predicate varargsParams(Parameter p, Type t) {
   p.getCallable().fromSource() and

java/ql/test/kotlin/library-tests/vararg/test.kt

@@ -1,6 +1,6 @@
 
 fun sink(sunk: Int) {
-    
+
 }
 
 open class HasVarargConstructor {
@@ -44,3 +44,13 @@ fun myFun() {
     HasVarargConstructor(*array)
     HasVarargConstructor("foo", *array)
 }
+
+open class X(
+    i: Int,
+    public vararg val s: String
+) { }
+
+fun fn(sl: List<String>) {
+    // reordered args:
+    val x = X(s = sl.toTypedArray(), i = 1)
+}