From 579acced998b4613adee1cf53828db80c62d2a5c Mon Sep 17 00:00:00 2001
From: Geza Lore <glore@tenstorrent.com>
Date: Sun, 22 Feb 2026 14:40:51 +0000
Subject: [PATCH] Internals: Make AstArg into an AstNode, not Expr (#7122)

---
 src/V3AstNodeExpr.h    | 40 ++++++++++++++++++----------------------
 src/V3DfgOptimizer.cpp |  4 ++--
 src/V3Inst.cpp         |  1 -
 src/V3Randomize.cpp    |  6 ++++++
 4 files changed, 26 insertions(+), 25 deletions(-)

diff --git a/src/V3AstNodeExpr.h b/src/V3AstNodeExpr.h
index 165f29933..c762ded81 100644
--- a/src/V3AstNodeExpr.h
+++ b/src/V3AstNodeExpr.h
@@ -502,6 +502,24 @@ public:
 
 // === Concrete node types =====================================================
 
+// === AstNode ===
+class AstArg final : public AstNode {
+    // An argument to a function/task, which is either an expression, or is a placeholder for an
+    // omitted argument.
+    // @astgen op1 := exprp : Optional[AstNodeExpr] // nullptr if omitted
+    std::string m_name;  // Argument name, or "" for number based interconnect
+public:
+    AstArg(FileLine* fl, const std::string& name, AstNodeExpr* exprp)
+        : ASTGEN_SUPER_Arg(fl)
+        , m_name{name} {
+        this->exprp(exprp);
+    }
+    ASTGEN_MEMBERS_AstArg;
+    std::string name() const override VL_MT_STABLE { return m_name; }
+    void name(const std::string& name) override { m_name = name; }
+    bool emptyConnectNoNext() const { return !exprp() && name() == "" && !nextp(); }
+};
+
 // === AstNodeExpr ===
 class AstAddrOfCFunc final : public AstNodeExpr {
     // Get address of CFunc
@@ -522,28 +540,6 @@ public:
     bool cleanOut() const override { return true; }
     AstCFunc* funcp() const { return m_funcp; }
 };
-class AstArg final : public AstNodeExpr {
-    // An argument to a function/task, which is either an expression, or is a placeholder for an
-    // omitted argument.
-    // TODO: AstArg should not be AstNodeExpr, but is currently used as such widely. Fix later.
-    // @astgen op1 := exprp : Optional[AstNodeExpr] // nullptr if omitted
-    string m_name;  // Pin name, or "" for number based interconnect
-public:
-    AstArg(FileLine* fl, const string& name, AstNodeExpr* exprp)
-        : ASTGEN_SUPER_Arg(fl)
-        , m_name{name} {
-        this->exprp(exprp);
-    }
-    ASTGEN_MEMBERS_AstArg;
-    bool hasDType() const override VL_MT_SAFE { return false; }
-    string name() const override VL_MT_STABLE { return m_name; }  // * = Pin name, ""=go by number
-    void name(const string& name) override { m_name = name; }
-    bool emptyConnectNoNext() const { return !exprp() && name() == "" && !nextp(); }
-
-    string emitVerilog() override { V3ERROR_NA_RETURN(""); }
-    string emitC() override { V3ERROR_NA_RETURN(""); }
-    bool cleanOut() const override { V3ERROR_NA_RETURN(true); }
-};
 class AstAttrOf final : public AstNodeExpr {
     // Return a value of a attribute, for example a LSB or array LSB of a signal
     // @astgen op1 := fromp : Optional[AstNode<AstNodeExpr|AstNodeDType>]
diff --git a/src/V3DfgOptimizer.cpp b/src/V3DfgOptimizer.cpp
index 78a21deb6..682008412 100644
--- a/src/V3DfgOptimizer.cpp
+++ b/src/V3DfgOptimizer.cpp
@@ -204,6 +204,7 @@ class DataflowExtractVisitor final : public VNVisitor {
     }
 
     void visit(AstNodeExpr* nodep) override { iterateChildrenConst(nodep); }
+    void visit(AstArg* nodep) override { iterateChildrenConst(nodep); }
 
     void visit(AstNodeVarRef* nodep) override {
         if (nodep->access().isWriteOrRW()) {
@@ -218,8 +219,7 @@ class DataflowExtractVisitor final : public VNVisitor {
     }
 
     void visit(AstNode* nodep) override {
-        // Conservatively assume unhandled nodes are impure. This covers all AstNodeFTaskRef
-        // as AstNodeFTaskRef are sadly not AstNodeExpr.
+        // Conservatively assume unhandled nodes are impure.
         m_impure = true;
         // Still need to gather all references/force/release, etc.
         iterateChildrenConst(nodep);
diff --git a/src/V3Inst.cpp b/src/V3Inst.cpp
index 834b3a2c2..5122eafbf 100644
--- a/src/V3Inst.cpp
+++ b/src/V3Inst.cpp
@@ -566,7 +566,6 @@ private:
     void visit(AstNode* nodep) override { iterateChildren(nodep); }
     void visit(AstNew* nodep) override { iterateChildren(nodep); }
     void visit(AstMethodCall* nodep) override { iterateChildren(nodep); }
-    void visit(AstArg* nodep) override { iterateChildren(nodep); }
 
 public:
     // CONSTRUCTORS
diff --git a/src/V3Randomize.cpp b/src/V3Randomize.cpp
index d0eb41e53..621206d63 100644
--- a/src/V3Randomize.cpp
+++ b/src/V3Randomize.cpp
@@ -699,6 +699,12 @@ class RandomizeMarkVisitor final : public VNVisitor {
                      || (nodep->op3p() && nodep->op3p()->user1())
                      || (nodep->op4p() && nodep->op4p()->user1()));
     }
+    void visit(AstArg* nodep) override {
+        iterateChildrenConst(nodep);
+        if (!m_constraintExprGenp && !m_inStdWith) return;
+        nodep->user1(nodep->exprp() && nodep->exprp()->user1());
+    }
+
     void visit(AstNode* nodep) override { iterateChildrenConst(nodep); }
 
 public: