Merge pull request #21490 from aschackmull/csharp/enclosing-obinit

C#: Add ObjectInitMethod as enclosing callable for the instance initializers.

Author: aschackmull

csharp/ql/lib/semmle/code/csharp/Callable.qll

@@ -336,6 +336,22 @@ class ExtensionTypeExtensionMethod extends ExtensionMethodImpl {
   ExtensionTypeExtensionMethod() { this.isInExtension() }
 }
 
+/**
+ * A non-static member with an initializer, for example a field `int Field = 0`.
+ */
+private class InitializedInstanceMember extends Member {
+  private AssignExpr ae;
+
+  InitializedInstanceMember() {
+    not this.isStatic() and
+    expr_parent_top_level(ae, _, this) and
+    not ae = getExpressionBody(_)
+  }
+
+  /** Gets the initializer expression. */
+  AssignExpr getInitializer() { result = ae }
+}
+
 /**
  * An object initializer method.
  *
@@ -347,6 +363,17 @@ class ExtensionTypeExtensionMethod extends ExtensionMethodImpl {
  */
 class ObjectInitMethod extends Method {
   ObjectInitMethod() { this.getName() = "<object initializer>" }
+
+  /**
+   * Holds if this object initializer method performs the initialization
+   * of a member via assignment `init`.
+   */
+  predicate initializes(AssignExpr init) {
+    exists(InitializedInstanceMember m |
+      this.getDeclaringType().getAMember() = m and
+      init = m.getInitializer()
+    )
+  }
 }
 
 /**

csharp/ql/lib/semmle/code/csharp/ExprOrStmtParent.qll

@@ -214,6 +214,8 @@ private module Cached {
     parent*(enclosingStart(cfe), c.(Constructor).getInitializer())
     or
     parent*(cfe, c.(Constructor).getObjectInitializerCall())
+    or
+    parent*(cfe, any(AssignExpr init | c.(ObjectInitMethod).initializes(init)))
   }
 
   /** Holds if the enclosing statement of expression `e` is `s`. */

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

@@ -10,42 +10,15 @@ private import semmle.code.csharp.ExprOrStmtParent
 private import semmle.code.csharp.commons.Compilation
 
 private module Initializers {
-  /**
-   * A non-static member with an initializer, for example a field `int Field = 0`.
-   */
-  class InitializedInstanceMember extends Member {
-    private AssignExpr ae;
-
-    InitializedInstanceMember() {
-      not this.isStatic() and
-      expr_parent_top_level(ae, _, this) and
-      not ae = any(Callable c).getExpressionBody()
-    }
-
-    /** Gets the initializer expression. */
-    AssignExpr getInitializer() { result = ae }
-  }
-
-  /**
-   * Holds if `obinit` is an object initializer method that performs the initialization
-   * of a member via assignment `init`.
-   */
-  predicate obinitInitializes(ObjectInitMethod obinit, AssignExpr init) {
-    exists(InitializedInstanceMember m |
-      obinit.getDeclaringType().getAMember() = m and
-      init = m.getInitializer()
-    )
-  }
-
   /**
    * Gets the `i`th member initializer expression for object initializer method `obinit`
    * in compilation `comp`.
    */
   AssignExpr initializedInstanceMemberOrder(ObjectInitMethod obinit, CompilationExt comp, int i) {
-    obinitInitializes(obinit, result) and
+    obinit.initializes(result) and
     result =
       rank[i + 1](AssignExpr ae0, Location l |
-        obinitInitializes(obinit, ae0) and
+        obinit.initializes(ae0) and
         l = ae0.getLocation() and
         getCompilation(l.getFile()) = comp
       |
@@ -74,7 +47,7 @@ class CfgScope extends Element, @top_level_exprorstmt_parent {
         any(Callable c |
           c.(Constructor).hasInitializer()
           or
-          Initializers::obinitInitializes(c, _)
+          c.(ObjectInitMethod).initializes(_)
           or
           c.hasBody()
         )

csharp/ql/test/library-tests/dispatch/CallGraph.expected

@@ -24,6 +24,7 @@
 | ExactCallable.cs:15:25:15:35 | Run`2 | ExactCallable.cs:172:21:172:33 | MethodWithOut |
 | ExactCallable.cs:15:25:15:35 | Run`2 | ExactCallable.cs:177:21:177:34 | MethodWithOut2 |
 | ExactCallable.cs:182:21:182:22 | M1 | ExactCallable.cs:187:21:187:22 | M2 |
+| TypeFlow.cs:3:7:3:14 | <object initializer> | TypeFlow.cs:22:20:22:22 | set_Prop |
 | TypeFlow.cs:5:5:5:12 | TypeFlow | TypeFlow.cs:24:10:24:12 | Run |
 | TypeFlow.cs:24:10:24:12 | Run | TypeFlow.cs:12:29:12:34 | Method |
 | TypeFlow.cs:24:10:24:12 | Run | TypeFlow.cs:17:30:17:35 | Method |

csharp/ql/test/library-tests/structuralcomparison/structuralComparison.expected

@@ -56,11 +56,11 @@ gvn
 | StructuralComparison.cs:3:14:3:18 | this access | (kind:Expr(12),false,Class) |
 | StructuralComparison.cs:3:14:3:18 | {...} | (kind:Stmt(1)) |
 | StructuralComparison.cs:5:26:5:26 | access to field x | (kind:Expr(16),true,x) |
-| StructuralComparison.cs:5:26:5:26 | this access | (kind:Expr(12)) |
+| StructuralComparison.cs:5:26:5:26 | this access | (kind:Expr(12),false,Class) |
 | StructuralComparison.cs:5:26:5:30 | ... = ... | ((kind:Expr(16),true,x) :: (0 :: (kind:Expr(63)))) |
 | StructuralComparison.cs:5:30:5:30 | 0 | 0 |
 | StructuralComparison.cs:6:26:6:26 | access to field y | (kind:Expr(16),true,y) |
-| StructuralComparison.cs:6:26:6:26 | this access | (kind:Expr(12)) |
+| StructuralComparison.cs:6:26:6:26 | this access | (kind:Expr(12),false,Class) |
 | StructuralComparison.cs:6:26:6:30 | ... = ... | ((kind:Expr(16),true,y) :: (1 :: (kind:Expr(63)))) |
 | StructuralComparison.cs:6:30:6:30 | 1 | 1 |
 | StructuralComparison.cs:8:24:8:24 | 0 | 0 |