From 004f4be5fb43ad3ef9dc427c6deb6ecdca2fa3ed Mon Sep 17 00:00:00 2001
From: Chris Smowton <smowton@github.com>
Date: Tue, 25 Oct 2022 17:09:05 +0100
Subject: [PATCH] Kotlin: don't try to call nonexistent `j.l.Number.toChar`

Previously we thought this could be callable because Kotlin's view of `j.l.Integer` inherits `k.Number` which defines `toChar`.
---
 java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt  | 1 +
 .../call-int-to-char/CONSISTENCY/javaEquivalent.expected      | 1 +
 .../test/kotlin/library-tests/call-int-to-char/test.expected  | 1 +
 java/ql/test/kotlin/library-tests/call-int-to-char/test.kt    | 1 +
 java/ql/test/kotlin/library-tests/call-int-to-char/test.ql    | 4 ++++
 5 files changed, 8 insertions(+)
 create mode 100644 java/ql/test/kotlin/library-tests/call-int-to-char/CONSISTENCY/javaEquivalent.expected
 create mode 100644 java/ql/test/kotlin/library-tests/call-int-to-char/test.expected
 create mode 100644 java/ql/test/kotlin/library-tests/call-int-to-char/test.kt
 create mode 100644 java/ql/test/kotlin/library-tests/call-int-to-char/test.ql

diff --git a/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt b/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt
index fd9ec136104..613c973f3c3 100644
--- a/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt
+++ b/java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt
@@ -1281,6 +1281,7 @@ open class KotlinUsesExtractor(
                         }
                         // Look for an exact type match...
                         javaClass.declarations.findSubType<IrFunction> { decl ->
+                            !decl.isFakeOverride &&
                             decl.name.asString() == jvmName &&
                             decl.valueParameters.size == f.valueParameters.size &&
                             decl.valueParameters.zip(f.valueParameters).all { p -> erase(p.first.type).classifierOrNull == erase(p.second.type).classifierOrNull }
diff --git a/java/ql/test/kotlin/library-tests/call-int-to-char/CONSISTENCY/javaEquivalent.expected b/java/ql/test/kotlin/library-tests/call-int-to-char/CONSISTENCY/javaEquivalent.expected
new file mode 100644
index 00000000000..02fc2a94b39
--- /dev/null
+++ b/java/ql/test/kotlin/library-tests/call-int-to-char/CONSISTENCY/javaEquivalent.expected
@@ -0,0 +1 @@
+| file://:0:0:0:0 | Couldn't find a Java equivalent function to kotlin.Int.toChar in java.lang.Integer |
diff --git a/java/ql/test/kotlin/library-tests/call-int-to-char/test.expected b/java/ql/test/kotlin/library-tests/call-int-to-char/test.expected
new file mode 100644
index 00000000000..c3ee02d7bd6
--- /dev/null
+++ b/java/ql/test/kotlin/library-tests/call-int-to-char/test.expected
@@ -0,0 +1 @@
+| test.kt:1:19:1:26 | toChar(...) |
diff --git a/java/ql/test/kotlin/library-tests/call-int-to-char/test.kt b/java/ql/test/kotlin/library-tests/call-int-to-char/test.kt
new file mode 100644
index 00000000000..d602aeb0992
--- /dev/null
+++ b/java/ql/test/kotlin/library-tests/call-int-to-char/test.kt
@@ -0,0 +1 @@
+fun f(x: Int) = x.toChar()
diff --git a/java/ql/test/kotlin/library-tests/call-int-to-char/test.ql b/java/ql/test/kotlin/library-tests/call-int-to-char/test.ql
new file mode 100644
index 00000000000..ab60ba2525d
--- /dev/null
+++ b/java/ql/test/kotlin/library-tests/call-int-to-char/test.ql
@@ -0,0 +1,4 @@
+import java
+
+from MethodAccess ma
+select ma