Merge pull request github#20512 from geoffw0/stmtlist

Rust: Improve StmtList

Author: geoffw0

rust/ql/.generated.list

@@ -266,23 +266,16 @@ module ExprTrees {
     }
   }
 
-  private AstNode getBlockChildNode(BlockExpr b, int i) {
-    result = b.getStmtList().getStatement(i)
-    or
-    i = b.getStmtList().getNumberOfStatements() and
-    result = b.getStmtList().getTailExpr()
-  }
-
   class AsyncBlockExprTree extends StandardTree, PreOrderTree, PostOrderTree, AsyncBlockExpr {
-    override AstNode getChildNode(int i) { result = getBlockChildNode(this, i) }
+    override AstNode getChildNode(int i) { result = this.getStmtList().getStmtOrExpr(i) }
 
     override predicate propagatesAbnormal(AstNode child) { none() }
   }
 
   class BlockExprTree extends StandardPostOrderTree, BlockExpr {
     BlockExprTree() { not this.isAsync() }
 
-    override AstNode getChildNode(int i) { result = getBlockChildNode(this, i) }
+    override AstNode getChildNode(int i) { result = this.getStmtList().getStmtOrExpr(i) }
 
     override predicate propagatesAbnormal(AstNode child) { child = this.getChildNode(_) }
   }

rust/ql/.gitattributes

@@ -1,4 +1,3 @@
-// generated by codegen, remove this comment if you wish to edit this file
 /**
  * This module provides a hand-modifiable wrapper around the generated class `StmtList`.
  *
@@ -12,17 +11,48 @@ private import codeql.rust.elements.internal.generated.StmtList
  * be referenced directly.
  */
 module Impl {
+  // the following QLdoc is generated: if you need to edit it, do it in the schema file
   /**
-   * A list of statements in a block.
+   * A list of statements in a block, with an optional tail expression at the
+   * end that determines the block's value.
    *
    * For example:
    * ```rust
    * {
    *     let x = 1;
    *     let y = 2;
+   *     x + y
    * }
    * //  ^^^^^^^^^
    * ```
    */
-  class StmtList extends Generated::StmtList { }
+  class StmtList extends Generated::StmtList {
+    /**
+     * Gets the `index`th statement or expression of this statement list (0-based).
+     *
+     * This includes both the statements and any tail expression in the statement list. To access
+     * just the statements, use `getStatement`. To access just the tail expression, if any,
+     * use `getTailExpr`.
+     */
+    AstNode getStmtOrExpr(int index) {
+      result = this.getStatement(index)
+      or
+      index = this.getNumberOfStatements() and
+      result = this.getTailExpr()
+    }
+
+    /**
+     * Gets any of the statements or expressions of this statement list.
+     *
+     * This includes both the statements and any tail expression in the statement list. To access
+     * just the statements, use `getAStatement`. To access just the tail expression, if any,
+     * use `getTailExpr`.
+     */
+    final AstNode getAStmtOrExpr() { result = this.getStmtOrExpr(_) }
+
+    /**
+     * Gets the number of statements or expressions of this statement list.
+     */
+    final int getNumberOfStmtOrExpr() { result = count(int i | exists(this.getStmtOrExpr(i))) }
+  }
 }

rust/ql/lib/codeql/rust/controlflow/internal/ControlFlowGraphImpl.qll

@@ -1,9 +1,10 @@
 instances
-| gen_stmt_list.rs:3:27:12:1 | StmtList |
-| gen_stmt_list.rs:7:5:10:5 | StmtList |
+| gen_stmt_list.rs:3:27:14:1 | StmtList |
+| gen_stmt_list.rs:8:5:12:5 | StmtList |
 getAttr
 getStatement
-| gen_stmt_list.rs:7:5:10:5 | StmtList | 0 | gen_stmt_list.rs:8:9:8:18 | let ... = 1 |
-| gen_stmt_list.rs:7:5:10:5 | StmtList | 1 | gen_stmt_list.rs:9:9:9:18 | let ... = 2 |
+| gen_stmt_list.rs:8:5:12:5 | StmtList | 0 | gen_stmt_list.rs:9:9:9:18 | let ... = 1 |
+| gen_stmt_list.rs:8:5:12:5 | StmtList | 1 | gen_stmt_list.rs:10:9:10:18 | let ... = 2 |
 getTailExpr
-| gen_stmt_list.rs:3:27:12:1 | StmtList | gen_stmt_list.rs:7:5:10:5 | { ... } |
+| gen_stmt_list.rs:3:27:14:1 | StmtList | gen_stmt_list.rs:8:5:12:5 | { ... } |
+| gen_stmt_list.rs:8:5:12:5 | StmtList | gen_stmt_list.rs:11:9:11:13 | ... + ... |