unified: Handle string segments in Expr.getStringValue()

Author: asgerf

unified/ql/lib/codeql/unified/internal/FacadeAst.qll

@@ -53,7 +53,13 @@ module Unified {
     string getStringValue() {
       // TODO: we'll want to cook the string literals extractor-side, but for now
       // just strip the quotes here and ignore escape sequences.
-      result = this.(StringLiteral).getValue().regexpCapture("\"(.*)\"", 1)
+      exists(string text | text = this.(StringLiteral).getValue() |
+        result = text.regexpCapture("\"(.*)\"", 1)
+        or
+        // Constant-segments of string interpolations are represented as string literals, but their raw text does not have quotes
+        not exists(text.regexpCapture("\"(.*)\"", 1)) and
+        result = text
+      )
     }
 
     /** Gets the immediately-enclosing expression, skipping over intermediate sub-nodes like `Argument`, and without crossing a function boundary. */

unified/ql/test/library-tests/BasicTest/test.expected

@@ -165,3 +165,9 @@ rawStringValue
 | strings.swift:4:27:4:32 |  world |  world |
 exprStringValue
 | strings.swift:1:10:1:16 | "hello" | hello |
+| strings.swift:2:11:2:16 | hello  | hello  |
+| strings.swift:2:23:2:28 |  world |  world |
+| strings.swift:3:11:3:16 | hello  | hello  |
+| strings.swift:3:28:3:33 |  world |  world |
+| strings.swift:4:11:4:16 | hello  | hello  |
+| strings.swift:4:27:4:32 |  world |  world |