From 981c28e7903bac6d922d35d5ee5726ce398e7ef6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Povi=C5=A1er?= <povik@cutebit.org>
Date: Thu, 14 Nov 2024 23:28:49 +0100
Subject: [PATCH] Fix a case of false type equivalency (#1175)

---
 source/ast/types/Type.cpp         |  5 ++---
 tests/unittests/ast/TypeTests.cpp | 28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/source/ast/types/Type.cpp b/source/ast/types/Type.cpp
index abf00af64..fab0de8e1 100644
--- a/source/ast/types/Type.cpp
+++ b/source/ast/types/Type.cpp
@@ -426,10 +426,9 @@ bool Type::isMatching(const Type& rhs) const {
     if (l == r)
         return true;
 
-    if (l->getSyntax() && l->getSyntax() == r->getSyntax() &&
-        l->getParentScope() == r->getParentScope()) {
+    if (l->getSyntax() && l->getSyntax() == r->getSyntax() && l->getParentScope() &&
+        l->getParentScope() == r->getParentScope())
         return true;
-    }
 
     // Special casing for type synonyms: real/realtime
     if (l->isFloating() && r->isFloating()) {
diff --git a/tests/unittests/ast/TypeTests.cpp b/tests/unittests/ast/TypeTests.cpp
index eb6a51356..29aa2d84a 100644
--- a/tests/unittests/ast/TypeTests.cpp
+++ b/tests/unittests/ast/TypeTests.cpp
@@ -2244,3 +2244,31 @@ TEST_CASE("Virtual interface element select of member") {
     compilation.addSyntaxTree(tree);
     NO_COMPILATION_ERRORS;
 }
+
+TEST_CASE("Hierarchy-dependent type equivalence") {
+    auto tree = SyntaxTree::fromText(R"(
+    interface iface #(parameter int WIDTH = 1)();
+        typedef struct packed {
+            bit [3:0] op;
+        } t;
+        t [WIDTH-1:0] ready;
+    endinterface
+
+    module top();
+        iface #(.WIDTH(1)) if1();
+        iface #(.WIDTH(2)) if2();
+    endmodule
+)");
+
+    Compilation compilation;
+    compilation.addSyntaxTree(tree);
+    NO_COMPILATION_ERRORS;
+
+    const InstanceBodySymbol& top = compilation.getRoot().lookupName<InstanceSymbol>("top").body;
+    const Type* type1 =
+        &top.lookupName<InstanceSymbol>("if1").body.lookupName<VariableSymbol>("ready").getType();
+    const Type* type2 =
+        &top.lookupName<InstanceSymbol>("if2").body.lookupName<VariableSymbol>("ready").getType();
+
+    CHECK(!type1->isEquivalent(*type2));
+}