Rust: Add a test of flow sources reaching sinks as well.

Author: geoffw0

rust/ql/test/library-tests/dataflow/sources/InlineFlow.expected

@@ -0,0 +1,21 @@
+import rust
+import codeql.rust.dataflow.DataFlow
+import codeql.rust.Concepts
+import utils.InlineFlowTest
+
+/**
+ * Configuration for flow from any threat model source to an argument of a function called `sink`.
+ */
+module MyFlowConfig implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node source) { source instanceof ThreatModelSource }
+
+  predicate isSink(DataFlow::Node sink) {
+    any(CallExpr call | call.getExpr().(PathExpr).getPath().toString() = "sink")
+        .getArgList()
+        .getAnArg() = sink.asExpr()
+  }
+}
+
+module MyFlowTest = TaintFlowTest<MyFlowConfig>;
+
+import MyFlowTest