Rust: Exclude data flow inconsistencies that stem from other inconsistencies

Author: paldepind

rust/ql/consistency-queries/DataFlowConsistency.ql

@@ -5,12 +5,4 @@
  * @id rust/diagnostics/data-flow-consistency
  */
 
-import codeql.rust.dataflow.DataFlow::DataFlow as DataFlow
-private import rust
-private import codeql.rust.dataflow.internal.DataFlowImpl
-private import codeql.rust.dataflow.internal.TaintTrackingImpl
-private import codeql.dataflow.internal.DataFlowImplConsistency
-
-private module Input implements InputSig<Location, RustDataFlow> { }
-
-import MakeConsistency<Location, RustDataFlow, RustTaintTracking, Input>
+import codeql.rust.dataflow.internal.DataFlowConsistency

rust/ql/lib/codeql/rust/AstConsistency.qll

@@ -21,6 +21,11 @@ query predicate multipleToStrings(Element e, string cls, string s) {
  */
 query predicate multipleLocations(Locatable e) { strictcount(e.getLocation()) > 1 }
 
+/**
+ * Holds if `e` does not have a `Location`.
+ */
+query predicate noLocation(Locatable e) { not exists(e.getLocation()) }
+
 private predicate multiplePrimaryQlClasses(Element e) {
   strictcount(string cls | cls = e.getAPrimaryQlClass() and cls != "VariableAccess") > 1
 }
@@ -58,6 +63,9 @@ int getAstInconsistencyCounts(string type) {
   type = "Multiple locations" and
   result = count(Element e | multipleLocations(e) | e)
   or
+  type = "No location" and
+  result = count(Element e | noLocation(e) | e)
+  or
   type = "Multiple primary QL classes" and
   result = count(Element e | multiplePrimaryQlClasses(e) | e)
   or

rust/ql/lib/codeql/rust/dataflow/internal/DataFlowConsistency.qll

@@ -0,0 +1,17 @@
+import codeql.rust.dataflow.DataFlow::DataFlow as DataFlow
+private import rust
+private import codeql.rust.dataflow.internal.DataFlowImpl
+private import codeql.rust.dataflow.internal.TaintTrackingImpl
+private import codeql.dataflow.internal.DataFlowImplConsistency
+
+private module Input implements InputSig<Location, RustDataFlow> {
+  predicate uniqueNodeLocationExclude(RustDataFlow::Node n) {
+    // Exclude nodes where the missing location can be explained by the
+    // underlying AST node not having a location.
+    not exists(n.asExpr().getLocation())
+  }
+
+  predicate missingLocationExclude(RustDataFlow::Node n) { not exists(n.asExpr().getLocation()) }
+}
+
+import MakeConsistency<Location, RustDataFlow, RustTaintTracking, Input>

rust/ql/src/queries/diagnostics/DataFlowConsistencyCounts.ql

@@ -5,17 +5,10 @@
  * @id rust/diagnostics/data-flow-consistency-counts
  */
 
-private import rust
-private import codeql.rust.dataflow.internal.DataFlowImpl
-private import codeql.rust.dataflow.internal.TaintTrackingImpl
-private import codeql.dataflow.internal.DataFlowImplConsistency
-
-private module Input implements InputSig<Location, RustDataFlow> { }
+import codeql.rust.dataflow.internal.DataFlowConsistency as Consistency
 
 // see also `rust/diagnostics/data-flow-consistency`, which lists the
 // individual inconsistency results.
 from string type, int num
-where
-  num =
-    MakeConsistency<Location, RustDataFlow, RustTaintTracking, Input>::getInconsistencyCounts(type)
+where num = Consistency::getInconsistencyCounts(type)
 select type, num

rust/ql/test/extractor-tests/generated/MacroItems/CONSISTENCY/AstConsistency.expected

@@ -0,0 +1,42 @@
+noLocation
+| file://:0:0:0:0 | ... .parent(...) |
+| file://:0:0:0:0 | ... .unwrap(...) |
+| file://:0:0:0:0 | ...: ... |
+| file://:0:0:0:0 | ...::Path |
+| file://:0:0:0:0 | ...::path |
+| file://:0:0:0:0 | ArgList |
+| file://:0:0:0:0 | ArgList |
+| file://:0:0:0:0 | MacroItems |
+| file://:0:0:0:0 | ParamList |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | Path |
+| file://:0:0:0:0 | RefType |
+| file://:0:0:0:0 | RefType |
+| file://:0:0:0:0 | RetType |
+| file://:0:0:0:0 | StmtList |
+| file://:0:0:0:0 | Use |
+| file://:0:0:0:0 | UseTree |
+| file://:0:0:0:0 | fn get_parent |
+| file://:0:0:0:0 | get_parent |
+| file://:0:0:0:0 | parent |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | path |
+| file://:0:0:0:0 | std |
+| file://:0:0:0:0 | std |
+| file://:0:0:0:0 | std |
+| file://:0:0:0:0 | unwrap |
+| file://:0:0:0:0 | { ... } |

rust/ql/test/extractor-tests/generated/MacroItems/CONSISTENCY/DataFlowConsistency.expected

@@ -2,3 +2,4 @@
 | Multiple parents | 0 |
 | Multiple primary QL classes | 0 |
 | Multiple toStrings | 0 |
+| No location | 0 |