Foreach stmt

Addded support for the foreach stmt (for now only the "canonical" desugaring).
Added a test and updated the expected output.

Author: AndreiDiaconu1

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/internal/TranslatedElement.qll

@@ -269,7 +269,11 @@ newtype TTranslatedElement =
     )
   } or
   // A local declaration
-  TTranslatedDeclaration(LocalVariableDeclExpr entry) or
+  TTranslatedDeclaration(LocalVariableDeclExpr entry) {
+    // foreach var decl and init is treated separately,
+    // because foreach needs desugaring
+    not entry.getParent() instanceof ForeachStmt
+  } or
   // A compiler generated element, generated by `generatedBy` during the 
   // desugaring process
   TTranslatedCompilerGeneratedElement(Element generatedBy, int index) {

csharp/ql/src/semmle/code/csharp/ir/implementation/raw/internal/TranslatedStmt.qll

@@ -11,6 +11,7 @@ private import TranslatedInitialization
 private import common.TranslatedConditionBlueprint
 private import IRInternal
 private import semmle.code.csharp.ir.internal.IRUtilities
+private import desugar.Foreach
 
 TranslatedStmt getTranslatedStmt(Stmt stmt) { result.getAST() = stmt }
 
@@ -853,3 +854,35 @@ class TranslatedSwitchStmt extends TranslatedStmt {
     )
   }
 }
+
+class TranslatedEnumeratorForeach extends TranslatedLoop {
+  override ForeachStmt stmt;
+
+  override TranslatedElement getChild(int id) {
+    id = 0 and result = getTempEnumDecl() or
+    id = 1 and result = getTry()
+  }
+
+  override Instruction getFirstInstruction() {
+    result = getTempEnumDecl().getFirstInstruction()
+  }
+
+  override Instruction getChildSuccessor(TranslatedElement child) {
+    (
+      child = getTempEnumDecl() and
+      result = getTry().getFirstInstruction()
+    ) or
+    (
+      child = getTry() and
+      result = getParent().getChildSuccessor(this)
+    )
+  }
+
+  private TranslatedElement getTry() {
+    result = ForeachElements::getTry(stmt)
+  }
+
+  private TranslatedElement getTempEnumDecl() {
+    result = ForeachElements::getEnumDecl(stmt)
+  }
+}