From a94601c8c0059ddad530f81852dfc91cf4799c3a Mon Sep 17 00:00:00 2001
From: Chris Smowton <chris@smowton.net>
Date: Tue, 3 Sep 2024 17:56:24 +0100
Subject: [PATCH] Add test checking for entity counts and def-use matches under
 aliasing

---
 .../semmle/go/aliases/defsuses.go             | 16 ++++++++
 .../semmle/go/aliases/test.expected           | 33 +++++++++++++++++
 .../library-tests/semmle/go/aliases/test.ql   | 37 +++++++++++++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 go/ql/test/library-tests/semmle/go/aliases/defsuses.go
 create mode 100644 go/ql/test/library-tests/semmle/go/aliases/test.expected
 create mode 100644 go/ql/test/library-tests/semmle/go/aliases/test.ql

diff --git a/go/ql/test/library-tests/semmle/go/aliases/defsuses.go b/go/ql/test/library-tests/semmle/go/aliases/defsuses.go
new file mode 100644
index 000000000000..9672b82504c9
--- /dev/null
+++ b/go/ql/test/library-tests/semmle/go/aliases/defsuses.go
@@ -0,0 +1,16 @@
+package aliases
+
+type IntAlias = int
+
+type S1 = struct{ x int }
+type S2 = struct{ x IntAlias }
+
+func Test1() int {
+	obj := S1{1}
+	obj.x = 2
+
+	var ptr *S2
+	ptr = &S1
+
+	return ptr.x
+}
diff --git a/go/ql/test/library-tests/semmle/go/aliases/test.expected b/go/ql/test/library-tests/semmle/go/aliases/test.expected
new file mode 100644
index 000000000000..92ffe12acdf1
--- /dev/null
+++ b/go/ql/test/library-tests/semmle/go/aliases/test.expected
@@ -0,0 +1,33 @@
+lowLevelDefs
+| defsuses.go:3:6:3:13 | IntAlias | defsuses.go:3:6:3:13 | IntAlias (1 declaration sites) |
+| defsuses.go:5:6:5:7 | S1 | defsuses.go:5:6:5:7 | S1 (1 declaration sites) |
+| defsuses.go:5:20:5:20 | x | defsuses.go:5:20:5:20 | x (2 declaration sites) |
+| defsuses.go:5:20:5:20 | x | defsuses.go:6:20:6:20 | x (2 declaration sites) |
+| defsuses.go:6:6:6:7 | S2 | defsuses.go:6:6:6:7 | S2 (1 declaration sites) |
+| defsuses.go:6:20:6:20 | x | defsuses.go:5:20:5:20 | x (2 declaration sites) |
+| defsuses.go:6:20:6:20 | x | defsuses.go:6:20:6:20 | x (2 declaration sites) |
+| defsuses.go:8:6:8:10 | Test1 | defsuses.go:8:6:8:10 | Test1 (1 declaration sites) |
+| defsuses.go:9:2:9:4 | obj | defsuses.go:9:2:9:4 | obj (1 declaration sites) |
+| defsuses.go:12:6:12:8 | ptr | defsuses.go:12:6:12:8 | ptr (1 declaration sites) |
+lowLevelUses
+| defsuses.go:3:17:3:19 | int | file://:0:0:0:0 | int (0 declaration sites) |
+| defsuses.go:5:22:5:24 | int | file://:0:0:0:0 | int (0 declaration sites) |
+| defsuses.go:6:22:6:29 | IntAlias | defsuses.go:3:6:3:13 | IntAlias (1 declaration sites) |
+| defsuses.go:8:14:8:16 | int | file://:0:0:0:0 | int (0 declaration sites) |
+| defsuses.go:9:9:9:10 | S1 | defsuses.go:5:6:5:7 | S1 (1 declaration sites) |
+| defsuses.go:10:2:10:4 | obj | defsuses.go:9:2:9:4 | obj (1 declaration sites) |
+| defsuses.go:10:6:10:6 | x | defsuses.go:5:20:5:20 | x (2 declaration sites) |
+| defsuses.go:10:6:10:6 | x | defsuses.go:6:20:6:20 | x (2 declaration sites) |
+| defsuses.go:12:11:12:12 | S2 | defsuses.go:6:6:6:7 | S2 (1 declaration sites) |
+| defsuses.go:13:2:13:4 | ptr | defsuses.go:12:6:12:8 | ptr (1 declaration sites) |
+| defsuses.go:13:9:13:10 | S1 | defsuses.go:5:6:5:7 | S1 (1 declaration sites) |
+| defsuses.go:15:9:15:11 | ptr | defsuses.go:12:6:12:8 | ptr (1 declaration sites) |
+| defsuses.go:15:13:15:13 | x | defsuses.go:5:20:5:20 | x (2 declaration sites) |
+| defsuses.go:15:13:15:13 | x | defsuses.go:6:20:6:20 | x (2 declaration sites) |
+distinctDefinedXs
+| 1 |
+distinctUsedXs
+| 1 |
+fieldUseUsePairs
+| defsuses.go:10:6:10:6 | x | defsuses.go:15:13:15:13 | x |
+| defsuses.go:15:13:15:13 | x | defsuses.go:10:6:10:6 | x |
diff --git a/go/ql/test/library-tests/semmle/go/aliases/test.ql b/go/ql/test/library-tests/semmle/go/aliases/test.ql
new file mode 100644
index 000000000000..8881baa7b4d5
--- /dev/null
+++ b/go/ql/test/library-tests/semmle/go/aliases/test.ql
@@ -0,0 +1,37 @@
+import go
+
+newtype TEntityWithDeclInfo = MkEntityWithDeclInfo(Entity e)
+
+class EntityWithDeclInfo extends TEntityWithDeclInfo {
+  string toString() {
+    exists(Entity e | this = MkEntityWithDeclInfo(e) |
+      result = e.toString() + " (" + count(e.getDeclaration()) + " declaration sites)"
+    )
+  }
+
+  predicate hasLocationInfo(
+    string filepath, int startline, int startcolumn, int endline, int endcolumn
+  ) {
+    exists(Entity e | this = MkEntityWithDeclInfo(e) |
+      e.hasLocationInfo(filepath, startline, startcolumn, endline, endcolumn)
+    )
+  }
+}
+
+query predicate lowLevelDefs(Ident i, EntityWithDeclInfo ewrapped) {
+  exists(Entity e | ewrapped = MkEntityWithDeclInfo(e) | defs(i, e))
+}
+
+query predicate lowLevelUses(Ident i, EntityWithDeclInfo ewrapped) {
+  exists(Entity e | ewrapped = MkEntityWithDeclInfo(e) | uses(i, e))
+}
+
+query predicate distinctDefinedXs(int ct) {
+  ct = count(Entity e | defs(_, e) and e.toString() = "x")
+}
+
+query predicate distinctUsedXs(int ct) { ct = count(Entity e | uses(_, e) and e.toString() = "x") }
+
+query predicate fieldUseUsePairs(Ident i1, Ident i2) {
+  exists(Field e | uses(i1, e) and uses(i2, e) and i1 != i2)
+}