From 689abf3e87f82f253b2498b055f2cc844ad95f2c Mon Sep 17 00:00:00 2001
From: Evan Typanski <evan.typanski@corelight.com>
Date: Thu, 6 Mar 2025 15:00:30 -0500
Subject: [PATCH] Reject equivalent functions.

Fixes #1982
---
 hilti/toolchain/src/ast/types/function.cc          |  3 +++
 tests/Baseline/hilti.validation.duplicate-6/output |  4 ++++
 tests/hilti/validation/duplicate.hlt               | 13 +++++++++++++
 3 files changed, 20 insertions(+)
 create mode 100644 tests/Baseline/hilti.validation.duplicate-6/output

diff --git a/hilti/toolchain/src/ast/types/function.cc b/hilti/toolchain/src/ast/types/function.cc
index dcf9d914f..488bc43a2 100644
--- a/hilti/toolchain/src/ast/types/function.cc
+++ b/hilti/toolchain/src/ast/types/function.cc
@@ -28,6 +28,9 @@ bool type::Function::isResolved(node::CycleDetector* cd) const {
 }
 
 bool type::isValidOverload(Function* f1, Function* f2) {
+    if ( f1->flavor() != function::Flavor::Hook && areEquivalent(f1, f2) )
+        return false;
+
     const auto& params1 = f1->parameters();
     const auto& params2 = f2->parameters();
 
diff --git a/tests/Baseline/hilti.validation.duplicate-6/output b/tests/Baseline/hilti.validation.duplicate-6/output
new file mode 100644
index 000000000..38e9fa727
--- /dev/null
+++ b/tests/Baseline/hilti.validation.duplicate-6/output
@@ -0,0 +1,4 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+[error] <...>/duplicate.hlt:6:1-6:33: 'fail1' is not a valid overload; previous definition in <...>/duplicate.hlt:5:1-5:33
+[error] <...>/duplicate.hlt:9:1-9:72: 'fail2' is not a valid overload; previous definition in <...>/duplicate.hlt:8:1-8:60
+[error] hiltic: aborting after errors
diff --git a/tests/hilti/validation/duplicate.hlt b/tests/hilti/validation/duplicate.hlt
index 427496f1c..2bdacada5 100644
--- a/tests/hilti/validation/duplicate.hlt
+++ b/tests/hilti/validation/duplicate.hlt
@@ -70,3 +70,16 @@ function uint<16> fun(uint<8> a, uint<8> b = uint8(0)) {
 hilti::print(fun(uint8(1)));
 
 }
+
+# @TEST-START-NEXT
+
+module Foo {
+
+# Equivalent functions signatures should not be allowed.
+function void fail1() { return; }
+function void fail1() { return; }
+
+function string fail2(uint<8> x, string y) { return "hi!"; }
+function string fail2(uint<8> different, string names) { return "hi!"; }
+
+}