PS: Add more expression classes and a helper class for calls.

Author: MathiasVP

powershell/ql/lib/powershell.qll

@@ -70,7 +70,9 @@ import semmle.code.powershell.Pipeline
 import semmle.code.powershell.StringConstantExpression
 import semmle.code.powershell.MemberExpr
 import semmle.code.powershell.InvokeMemberExpression
+import semmle.code.powershell.Call
 import semmle.code.powershell.SubExpression
+import semmle.code.powershell.ErrorExpr
 import semmle.code.powershell.ConvertExpr
 import semmle.code.powershell.IndexExpr
 import semmle.code.powershell.HashTable

powershell/ql/lib/semmle/code/powershell/Call.qll

@@ -0,0 +1,29 @@
+import powershell
+
+abstract private class AbstractCall extends Ast {
+  abstract Expr getCommand();
+
+  abstract Expr getArgument(int i);
+
+  Expr getNamedArgument(string name) { none() }
+
+  Expr getQualifier() { none() }
+}
+
+private class CmdCall extends AbstractCall instanceof Cmd {
+  final override Expr getCommand() { result = Cmd.super.getCommand() }
+
+  final override Expr getArgument(int i) { result = Cmd.super.getArgument(i) }
+
+  final override Expr getNamedArgument(string name) { result = Cmd.super.getNamedArgument(name) }
+}
+
+private class InvokeMemberCall extends AbstractCall instanceof InvokeMemberExpr {
+  final override Expr getCommand() { result = super.getMember() }
+
+  final override Expr getArgument(int i) { result = InvokeMemberExpr.super.getArgument(i) }
+
+  final override Expr getQualifier() { result = InvokeMemberExpr.super.getQualifier() }
+}
+
+final class Call = AbstractCall;

powershell/ql/lib/semmle/code/powershell/Command.qll

@@ -15,6 +15,8 @@ class Cmd extends @command, CmdBase {
 
   CmdElement getElement(int i) { command_command_element(this, i, result) }
 
+  Expr getCommand() { result = this.getElement(0) }
+
   StringConstExpr getCmdName() { result = this.getElement(0) }
 
   Expr getArgument(int i) {
@@ -43,7 +45,7 @@ class Cmd extends @command, CmdBase {
 
 /**
  * An argument to a command.
- * 
+ *
  * The argument may be named or positional.
  */
 class Argument extends Expr {

powershell/ql/lib/semmle/code/powershell/ErrorExpr.qll

@@ -0,0 +1,7 @@
+import powershell
+
+class ErrorExpr extends @error_expression, Expr {
+  final override SourceLocation getLocation() { error_expression_location(this, result) }
+
+  final override string toString() { result = "error" }
+}