diff --git a/powershell/ql/lib/semmle/code/powershell/Call.qll b/powershell/ql/lib/semmle/code/powershell/Call.qll
index 53200c1ce0a..ae117801854 100644
--- a/powershell/ql/lib/semmle/code/powershell/Call.qll
+++ b/powershell/ql/lib/semmle/code/powershell/Call.qll
@@ -7,6 +7,8 @@ abstract private class AbstractCall extends Ast {
 
   Expr getNamedArgument(string name) { none() }
 
+  Expr getAnArgument() { result = this.getArgument(_) or result = this.getNamedArgument(_) }
+
   Expr getQualifier() { none() }
 }
 
diff --git a/powershell/ql/lib/semmle/code/powershell/Command.qll b/powershell/ql/lib/semmle/code/powershell/Command.qll
index 694162f2808..a81e6c2686c 100644
--- a/powershell/ql/lib/semmle/code/powershell/Command.qll
+++ b/powershell/ql/lib/semmle/code/powershell/Command.qll
@@ -1,11 +1,11 @@
 import powershell
 
 class Cmd extends @command, CmdBase {
-  override string toString() { result = this.getName() }
+  override string toString() { result = this.getCommandName() }
 
   override SourceLocation getLocation() { command_location(this, result) }
 
-  string getName() { command(this, result, _, _, _) }
+  string getCommandName() { command(this, result, _, _, _) }
 
   int getKind() { command(this, _, result, _, _) }
 
@@ -19,6 +19,8 @@ class Cmd extends @command, CmdBase {
 
   StringConstExpr getCmdName() { result = this.getElement(0) }
 
+  Expr getAnArgument() { result = this.getArgument(_) or result = this.getNamedArgument(_) }
+
   Expr getArgument(int i) {
     result =
       rank[i + 1](CmdElement e, int j |
diff --git a/powershell/ql/lib/semmle/code/powershell/CommentEntity.qll b/powershell/ql/lib/semmle/code/powershell/CommentEntity.qll
index cd46c8cb83f..d234eb0f3c7 100644
--- a/powershell/ql/lib/semmle/code/powershell/CommentEntity.qll
+++ b/powershell/ql/lib/semmle/code/powershell/CommentEntity.qll
@@ -1,9 +1,17 @@
 import powershell
 
 class Comment extends @comment_entity {
-  SourceLocation getLocation() { comment_entity_location(this, result) }
+  Location getLocation() { comment_entity_location(this, result) }
 
   StringLiteral getCommentContents() { comment_entity(this, result) }
 
-  string toString() { result = "Comment at: " + this.getLocation().toString() }
+  string toString() { result = this.getCommentContents().toString() }
+}
+
+class SingleLineComment extends Comment {
+  SingleLineComment() { this.getCommentContents().getNumContinuations() = 1 }
+}
+
+class MultiLineComment extends Comment {
+  MultiLineComment() { this.getCommentContents().getNumContinuations() > 1 }
 }
diff --git a/powershell/ql/lib/semmle/code/powershell/StringLiteral.qll b/powershell/ql/lib/semmle/code/powershell/StringLiteral.qll
index 77ece5d7d1c..a7f85ece8e4 100644
--- a/powershell/ql/lib/semmle/code/powershell/StringLiteral.qll
+++ b/powershell/ql/lib/semmle/code/powershell/StringLiteral.qll
@@ -1,14 +1,12 @@
 import powershell
 
 class StringLiteral extends @string_literal {
-  int getNumContinuations() { string_literal_line(this, result, _) }
+  int getNumContinuations() { result = strictcount(int i | exists(this.getContinuation(i))) }
 
   string getContinuation(int index) { string_literal_line(this, index, result) }
 
   /** Get the full string literal with all its parts concatenated */
-  string toString() {
-    result = this.getValue()
-  }
+  string toString() { result = this.getValue() }
 
   string getValue() {
     result = concat(int i | i = [0 .. this.getNumContinuations()] | this.getContinuation(i), "\n")
diff --git a/powershell/ql/lib/semmle/code/powershell/controlflow/internal/Completion.qll b/powershell/ql/lib/semmle/code/powershell/controlflow/internal/Completion.qll
index ac51896d0c4..d37d566ea0d 100644
--- a/powershell/ql/lib/semmle/code/powershell/controlflow/internal/Completion.qll
+++ b/powershell/ql/lib/semmle/code/powershell/controlflow/internal/Completion.qll
@@ -23,7 +23,7 @@ private newtype TCompletion =
 
 private predicate commandThrows(Cmd c, boolean unconditional) {
   c.getNamedArgument("ErrorAction").(StringConstExpr).getValue().getValue() = "Stop" and
-  if c.getName() = "Write-Error" then unconditional = true else unconditional = false
+  if c.getCommandName() = "Write-Error" then unconditional = true else unconditional = false
 }
 
 pragma[noinline]
diff --git a/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPrivate.qll b/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPrivate.qll
index 9bc578a6c7a..9da8705332e 100644
--- a/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPrivate.qll
+++ b/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPrivate.qll
@@ -41,6 +41,14 @@ private class ExprNodeImpl extends ExprNode, NodeImpl {
   override string toStringImpl() { result = this.getExprNode().toString() }
 }
 
+private class StmtNodeImpl extends StmtNode, NodeImpl {
+  override CfgScope getCfgScope() { none() /* TODO */ }
+
+  override Location getLocationImpl() { result = this.getStmtNode().getLocation() }
+
+  override string toStringImpl() { result = this.getStmtNode().toString() }
+}
+
 /** Gets the SSA definition node corresponding to parameter `p`. */
 pragma[nomagic]
 SsaImpl::DefinitionExt getParameterDef(Parameter p) {
@@ -61,7 +69,7 @@ module SsaFlow {
   Impl::Node asNode(Node n) {
     n = TSsaNode(result)
     or
-    result.(Impl::ExprNode).getExpr() = n.asExpr()
+    result.(Impl::ExprNode).getExpr() = n.asExpr() // TODO: Statement nodes?
     or
     result.(Impl::ExprPostUpdateNode).getExpr() = n.(PostUpdateNode).getPreUpdateNode().asExpr()
     or
@@ -98,6 +106,7 @@ private module Cached {
   cached
   newtype TNode =
     TExprNode(CfgNodes::ExprCfgNode n) or
+    TStmtNode(CfgNodes::StmtCfgNode n) or
     TSsaNode(SsaImpl::DataFlowIntegration::SsaNode node) or
     TNormalParameterNode(Parameter p) or
     TExprPostUpdateNode(CfgNodes::ExprCfgNode n) {
diff --git a/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPublic.qll b/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPublic.qll
index 1e91f1ea844..e197a4e5edf 100644
--- a/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPublic.qll
+++ b/powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPublic.qll
@@ -11,6 +11,8 @@ class Node extends TNode {
   /** Gets the expression corresponding to this node, if any. */
   CfgNodes::ExprCfgNode asExpr() { result = this.(ExprNode).getExprNode() }
 
+  CfgNodes::StmtCfgNode asStmt() { result = this.(StmtNode).getStmtNode() }
+
   /** Gets the parameter corresponding to this node, if any. */
   Parameter asParameter() { result = this.(ParameterNode).getParameter() }
 
@@ -47,6 +49,22 @@ class ExprNode extends Node, TExprNode {
   CfgNodes::ExprCfgNode getExprNode() { result = n }
 }
 
+/**
+ * A statement, viewed as a node in a data flow graph.
+ *
+ * Note that because of control-flow splitting, one `Stmt` may correspond
+ * to multiple `StmtNode`s, just like it may correspond to multiple
+ * `ControlFlow::Node`s.
+ */
+class StmtNode extends Node, TStmtNode {
+  private CfgNodes::StmtCfgNode n;
+
+  StmtNode() { this = TStmtNode(n) }
+
+  /** Gets the expression corresponding to this node. */
+  CfgNodes::StmtCfgNode getStmtNode() { result = n }
+}
+
 /**
  * The value of a parameter at function entry, viewed as a node in a data
  * flow graph.
@@ -103,6 +121,9 @@ private import Cached
 /** Gets a node corresponding to expression `e`. */
 ExprNode exprNode(CfgNodes::ExprCfgNode e) { result.getExprNode() = e }
 
+/** Gets a node corresponding to statement `s`. */
+StmtNode stmtNode(CfgNodes::StmtCfgNode e) { result.getStmtNode() = e }
+
 /**
  * Gets the node corresponding to the value of parameter `p` at function entry.
  */
diff --git a/powershell/ql/lib/semmle/code/powershell/dataflow/internal/TaintTrackingImplSpecific.qll b/powershell/ql/lib/semmle/code/powershell/dataflow/internal/TaintTrackingImplSpecific.qll
index a0a221ac169..ad7e6716094 100644
--- a/powershell/ql/lib/semmle/code/powershell/dataflow/internal/TaintTrackingImplSpecific.qll
+++ b/powershell/ql/lib/semmle/code/powershell/dataflow/internal/TaintTrackingImplSpecific.qll
@@ -2,7 +2,7 @@
  * Provides Powershell-specific definitions for use in the taint tracking library.
  */
 
-private import codeql.Locations
+private import powershell
 private import codeql.dataflow.TaintTracking
 private import DataFlowImplSpecific