Pull request overview

Refactors the C# QL libraries to simplify the SwitchStmt / CaseStmt AST surface and move prior switch/case “shape” handling into CFG construction, aiming to preserve overall behavior while reducing AST complexity.

Changes:

• Moves switch/case reordering and “case body” lookup logic into ControlFlowGraphImpl.qll.
• Simplifies SwitchStmt.getCase / SwitchStmt.getStmt to reflect direct child statement ordering.
• Removes the CaseStmt.getBody override and the prior SwithStmtInternal helper module from Stmt.qll.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

csharp/ql/lib/semmle/code/csharp/controlflow/internal/ControlFlowGraphImpl.qll:353

• The doc comment for SwithStmtInternal::getStmt (example indices + note about the statement after a case being a child of the labeled statement) appears to describe the old AST shape. After this refactor, switch section labels and section statements are separate children (see SwitchStmt.getStmt now delegating to getChildStmt), so this example/explanation is likely misleading and should be updated to reflect the current structure and what getStmt returns here.

  /**
   * Gets the `i`th statement in the body of this `switch` statement.
   *
   * Example:
   *
   * ```csharp
   * switch (x) {
   *   case "abc":              // i = 0
   *     return 0;
   *   case int i when i > 0:   // i = 1
   *     return 1;
   *   case string s:           // i = 2
   *     Console.WriteLine(s);
   *     return 2;              // i = 3
   *   default:                 // i = 4
   *     return 3;              // i = 5
   * }
   * ```
   *
   * Note that each non-`default` case is a labeled statement, so the statement
   * that follows is a child of the labeled statement, and not the `switch` block.
   */

You can also share your feedback on Copilot code review. Take the survey.

Looks plausible to me!