Python: nice locations for import aliases

These were computed wrongly before.

Author: yoff

python/ql/lib/analysis/DefinitionTracking.qll

@@ -492,9 +492,14 @@ class NiceLocationExpr extends Expr {
     // for `import xxx` or for `import xxx as yyy`.
     this.(ImportExpr).getLocation().hasLocationInfo(f, bl, bc, el, ec)
     or
-    /* Show y for `y` in `from xxx import y` */
-    exists(string name |
-      name = this.(ImportMember).getName() and
+    // Show y for `y` in `from xxx import y`
+    // and y for `yyy as y` in `from xxx import yyy as y`.
+    exists(string name, Alias alias |
+      // This alias will always exist, as `from xxx import y`
+      // is expanded to `from xxx imprt y as y`.
+      this = alias.getValue() and
+      name = alias.getAsname().(Name).getId()
+    |
       this.(ImportMember).getLocation().hasLocationInfo(f, _, _, el, ec) and
       bl = el and
       bc = ec - name.length() + 1

python/ql/test/library-tests/locations/imports/imports.expected

@@ -1,8 +1,6 @@
 | import_statements.py | 1 | 6 | 1 | 33 |
 | import_statements.py | 1 | 42 | 1 | 53 |
 | import_statements.py | 2 | 6 | 2 | 41 |
-| import_statements.py | 2 | 60 | 2 | 76 |
 | import_statements.py | 2 | 71 | 2 | 76 |
 | import_statements.py | 3 | 6 | 3 | 42 |
 | import_statements.py | 4 | 5 | 4 | 12 |
-| import_statements.py | 4 | -7 | 4 | 12 |