Rust: Fix variable access overlap

Author: hvitved

rust/ql/lib/codeql/rust/elements/internal/VariableImpl.qll

@@ -460,7 +460,12 @@ module Impl {
     VariableAccessCand cand, VariableScope scope, string name, int nestLevel, int ord
   ) {
     name = cand.getName() and
-    scope = [cand.(VariableScope), getEnclosingScope(cand)] and
+    (
+      scope = cand
+      or
+      not cand instanceof VariableScope and
+      scope = getEnclosingScope(cand)
+    ) and
     ord = getPreOrderNumbering(scope, cand) and
     nestLevel = 0
     or

rust/ql/test/library-tests/variables/CONSISTENCY/VariableConsistency.expected

@@ -283,7 +283,6 @@ read
 | main.rs:349:16:349:16 | x | main.rs:349:16:349:16 | x | main.rs:352:19:352:19 | x |
 | main.rs:354:20:354:20 | x | main.rs:354:20:354:20 | x | main.rs:357:19:357:19 | x |
 | main.rs:364:9:364:9 | x | main.rs:364:9:364:9 | x | main.rs:365:11:365:11 | x |
-| main.rs:364:9:364:9 | x | main.rs:364:9:364:9 | x | main.rs:367:20:367:20 | x |
 | main.rs:366:18:366:18 | x | main.rs:366:18:366:18 | x | main.rs:367:20:367:20 | x |
 | main.rs:373:5:373:6 | a8 | main.rs:373:5:373:6 | a8 | main.rs:379:15:379:16 | a8 |
 | main.rs:375:9:375:10 | b3 | main.rs:375:9:375:10 | b3 | main.rs:380:15:380:16 | b3 |
@@ -581,7 +580,6 @@ adjacentReads
 | main.rs:334:9:334:9 | x | main.rs:334:9:334:9 | x | main.rs:335:11:335:11 | x | main.rs:343:15:343:15 | x |
 | main.rs:348:9:348:9 | x | main.rs:348:9:348:9 | x | main.rs:350:7:350:7 | x | main.rs:355:7:355:7 | x |
 | main.rs:348:9:348:9 | x | main.rs:348:9:348:9 | x | main.rs:355:7:355:7 | x | main.rs:359:19:359:19 | x |
-| main.rs:364:9:364:9 | x | main.rs:364:9:364:9 | x | main.rs:365:11:365:11 | x | main.rs:367:20:367:20 | x |
 | main.rs:391:13:391:15 | a10 | main.rs:391:13:391:15 | a10 | main.rs:395:15:395:17 | a10 | main.rs:404:9:404:11 | a10 |
 | main.rs:392:13:392:14 | b4 | main.rs:392:13:392:14 | b4 | main.rs:396:15:396:16 | b4 | main.rs:405:9:405:10 | b4 |
 | main.rs:393:13:393:14 | c2 | main.rs:393:13:393:14 | c2 | main.rs:397:15:397:16 | c2 | main.rs:406:9:406:10 | c2 |

rust/ql/test/library-tests/variables/Ssa.expected

@@ -364,7 +364,7 @@ fn match_pattern15() {
     let x = Some(0); // x1
     match x { // $ read_access=x1
             Some(x) // x2
-                => x, // $ read_access=x2 $ SPURIOUS: read_access=x1
+                => x, // $ read_access=x2
             _ => 0
         };
 }

rust/ql/test/library-tests/variables/main.rs

@@ -232,7 +232,6 @@ variableAccess
 | main.rs:357:19:357:19 | x | main.rs:354:20:354:20 | x |
 | main.rs:359:19:359:19 | x | main.rs:348:9:348:9 | x |
 | main.rs:365:11:365:11 | x | main.rs:364:9:364:9 | x |
-| main.rs:367:20:367:20 | x | main.rs:364:9:364:9 | x |
 | main.rs:367:20:367:20 | x | main.rs:366:18:366:18 | x |
 | main.rs:379:15:379:16 | a8 | main.rs:373:5:373:6 | a8 |
 | main.rs:380:15:380:16 | b3 | main.rs:375:9:375:10 | b3 |
@@ -462,7 +461,6 @@ variableReadAccess
 | main.rs:357:19:357:19 | x | main.rs:354:20:354:20 | x |
 | main.rs:359:19:359:19 | x | main.rs:348:9:348:9 | x |
 | main.rs:365:11:365:11 | x | main.rs:364:9:364:9 | x |
-| main.rs:367:20:367:20 | x | main.rs:364:9:364:9 | x |
 | main.rs:367:20:367:20 | x | main.rs:366:18:366:18 | x |
 | main.rs:379:15:379:16 | a8 | main.rs:373:5:373:6 | a8 |
 | main.rs:380:15:380:16 | b3 | main.rs:375:9:375:10 | b3 |