diff --git a/src/V3Assert.cpp b/src/V3Assert.cpp
index fc29de08c..4540e5575 100644
--- a/src/V3Assert.cpp
+++ b/src/V3Assert.cpp
@@ -439,7 +439,9 @@ class AssertVisitor final : public VNVisitor {
             } else {
                 ++m_statAsNotImm;
             }
-            if (!passsp && !failsp) failsp = newFireAssertUnchecked(nodep, "'assert' failed.");
+            if (!passsp && !failsp)
+                failsp = newFireAssertUnchecked(
+                    nodep, VN_IS(nodep, AssertIntrinsic) ? "'$cast' failed." : "'assert' failed.");
         } else {
             nodep->v3fatalSrc("Unknown node type");
         }
diff --git a/test_regress/t/t_castdyn.v b/test_regress/t/t_castdyn.v
index d1b960150..c167c0927 100644
--- a/test_regress/t/t_castdyn.v
+++ b/test_regress/t/t_castdyn.v
@@ -9,76 +9,76 @@ endclass
 class BasedA extends Base;
 endclass
 class BasedB extends Base;
-   static function BasedB getBasedB(bit getNull);
-      BasedB b = new;
-      return getNull ? null : b;
-   endfunction
+  static function BasedB getBasedB(bit getNull);
+    BasedB b = new;
+    return getNull ? null : b;
+  endfunction
 endclass
 
 module t;
-   int i;
-   int a;
-   int ao;
+  int i;
+  int a;
+  int ao;
 
-   Base b;
-   Base bo;
-   BasedA ba;
-   BasedA bao;
-   BasedB bb;
-   BasedB bbo;
+  Base b;
+  Base bo;
+  BasedA ba;
+  BasedA bao;
+  BasedB bb;
+  BasedB bbo;
 
-   // verilator lint_off CASTCONST
+  // verilator lint_off CASTCONST
 
-   initial begin
-      a = 1234;
-      i = $cast(ao, a);
-      if (i != 1) $stop;
-      if (ao != 1234) $stop;
+  initial begin
+    a = 1234;
+    i = $cast(ao, a);
+    if (i != 1) $stop;
+    if (ao != 1234) $stop;
 
-      a = 12345;
-      $cast(ao, a);
-      if (ao != 12345) $stop;
+    a = 12345;
+    $cast(ao, a);
+    if (ao != 12345) $stop;
 
-      i = $cast(ao, 2.1 * 3.7);
-      if (i != 1) $stop;
-      if (ao != 8) $stop;
+    i = $cast(ao, 2.1 * 3.7);
+    if (i != 1) $stop;
+    if (ao != 8) $stop;
 
-      i = $cast(bo, null);
-      if (i != 1) $stop;
-      if (bo != null) $stop;
+    i = $cast(bo, null);
+    if (i != 1) $stop;
+    if (bo != null) $stop;
 
-      ba = new;
-      b = ba;
-      i = $cast(bao, b);
-      if (i != 1) $stop;
-      if (b != ba) $stop;
+    ba = new;
+    b = ba;
+    i = $cast(bao, b);
+    if (i != 1) $stop;
+    if (b != ba) $stop;
 
-      bb = new;
-      b = bb;
-      i = $cast(bbo, b);
-      if (i != 1) $stop;
-      if (b != bb) $stop;
+    bb = new;
+    b = bb;
+    i = $cast(bbo, b);
+    if (i != 1) $stop;
+    if (b != bb) $stop;
 
-      bb = null;
-      b = bb;
-      i = $cast(bbo, b);
-      if (i != 1) $stop;
-      if (b != bb) $stop;
+    bb = null;
+    b = bb;
+    i = $cast(bbo, b);
+    if (i != 1) $stop;
+    if (b != bb) $stop;
 
-      bb = BasedB::getBasedB(1);
-      b = bb;
-      i = $cast(bbo, b);
-      if (i != 1) $stop;
-      if (b != bb) $stop;
+    bb = BasedB::getBasedB(1);
+    b = bb;
+    i = $cast(bbo, b);
+    if (i != 1) $stop;
+    if (b != bb) $stop;
 
-      bb = new;
-      b = bb;
-      bao = ba;
-      i = $cast(bao, b);
-      if (i != 0) $stop;
-      if (bao != ba) $stop;  // Unchanged
+    bb = new;
+    b = bb;
+    bao = ba;
+    i = $cast(bao, b);
+    if (i != 0) $stop;
+    if (bao != ba) $stop;  // Unchanged
 
-      $write("*-* All Finished *-*\n");
-      $finish;
-   end
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
 endmodule
diff --git a/test_regress/t/t_castdyn_run_bad.out b/test_regress/t/t_castdyn_run_bad.out
index 3df579223..4cc3bde3a 100644
--- a/test_regress/t/t_castdyn_run_bad.out
+++ b/test_regress/t/t_castdyn_run_bad.out
@@ -1,3 +1,3 @@
-[0] %Error: t_castdyn_run_bad.v:32: Assertion failed in top.t: 'assert' failed.
-%Error: t/t_castdyn_run_bad.v:32: Verilog $stop
+[0] %Error: t_castdyn_run_bad.v:35: Assertion failed in top.t: '$cast' failed.
+%Error: t/t_castdyn_run_bad.v:35: Verilog $stop
 Aborting...
diff --git a/test_regress/t/t_castdyn_run_bad.v b/test_regress/t/t_castdyn_run_bad.v
index 26f8b1de1..2d657b6b8 100644
--- a/test_regress/t/t_castdyn_run_bad.v
+++ b/test_regress/t/t_castdyn_run_bad.v
@@ -12,26 +12,29 @@ class ExbaseB extends Base;
 endclass
 
 module t;
-   int i;
+  int i;
 
-   Base b;
-   ExbaseA ba, ba1;
-   ExbaseB bb, bb1;
+  Base b;
+  ExbaseA ba, ba1;
+  ExbaseB bb, bb1;
 
-   initial begin
-      ba = new;
-      b = ba;
-      i = $cast(ba1, b);
-      if (i != 1) $stop;
-      $cast(ba1, b);  // ok at runtime
+  initial begin
+    ba = new;
+    b = ba;
+    i = $cast(ba1, b);
+    if (i != 1) $stop;
+    $cast(ba1, b);  // ok at runtime
 
-      bb = new;
-      b = bb;
-      i = $cast(ba1, b);
-      if (i != 0) $stop;
-      $cast(ba1, b);
+    b = null;
+    $cast(ba1, b);  // no failure on null
 
-      $write("*-* All Finished *-*\n");
-      $finish;
-   end
+    bb = new;
+    b = bb;
+    i = $cast(ba1, b);
+    if (i != 0) $stop;
+    $cast(ba1, b);  // <-- Bad $cast task
+
+    $write("*-* All Finished *-*\n");
+    $finish;
+  end
 endmodule