Rust: Add logic for Vecs and slices.

Author: geoffw0

rust/ql/lib/codeql/rust/internal/TypeInference.qll

@@ -1140,10 +1140,17 @@ private Type inferForLoopExprType(AstNode n, TypePath path) {
   exists(ForExpr fe, Type iterableType, TypePath iterablePath |
     n = fe.getPat() and
     iterableType = inferType(fe.getIterable(), iterablePath) and
+    result = iterableType and
     (
-      iterablePath.isCons(any(ArrayTypeParameter tp), path) and
-      result = iterableType
-      // TODO: iterables (containers, ranges etc)
+      iterablePath.isCons(any(Vec v).getElementTypeParameter(), path)
+      or
+      iterablePath.isCons(any(ArrayTypeParameter tp), path)
+      or
+      exists(TypePath path0 |
+        iterablePath.isCons(any(RefTypeParameter tp), path0) and
+        path0.isCons(any(SliceTypeParameter tp), path)
+      )
+      // TODO: iterables (general case for containers, ranges etc)
     )
   )
 }

rust/ql/test/library-tests/type-inference/type-inference.expected

@@ -2792,6 +2792,8 @@ inferType
 | main.rs:1875:40:1875:40 | 2 |  | {EXTERNAL LOCATION} | u64 |
 | main.rs:1875:43:1875:43 | 3 |  | {EXTERNAL LOCATION} | i32 |
 | main.rs:1875:43:1875:43 | 3 |  | {EXTERNAL LOCATION} | u64 |
+| main.rs:1876:13:1876:13 | u |  | file://:0:0:0:0 | & |
+| main.rs:1876:13:1876:13 | u | &T | {EXTERNAL LOCATION} | u64 |
 | main.rs:1876:18:1876:22 | vals4 |  | {EXTERNAL LOCATION} | Vec |
 | main.rs:1876:18:1876:22 | vals4 | T | file://:0:0:0:0 | & |
 | main.rs:1876:18:1876:22 | vals4 | T.&T | {EXTERNAL LOCATION} | u64 |