diff --git a/Changes b/Changes
index e17a43cef..98fdc63f0 100644
--- a/Changes
+++ b/Changes
@@ -25,7 +25,7 @@ The contributors that suggested a given feature are shown in []. Thanks!
 ****  Fix multithreaded yield behavior when no work.  [Patrick Stewart]
 
 ****  Fix bad-syntax crashes, bug1548, bug1550-1553, bug1557-1560, bug1563,
-      bug1573, bug1574. [Eric Rippey]
+      bug1573-1575. [Eric Rippey]
 
 ****  Benchmark --protect-lib runtime, bug1519. [Todd Strader]
 
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 815bf5905..980fbdd1c 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -3491,6 +3491,10 @@ private:
         } else if (expDTypep->isString() && !underp->dtypep()->isString()) {
             underp = spliceCvtString(underp);
             underp = userIterateSubtreeReturnEdits(underp, WidthVP(SELF, FINAL).p());
+        } else if (VN_IS(underp, NodeDType)) {  // Note the node itself, not node's data type
+            underp->v3error(ucfirst(nodep->prettyOperatorName())
+                            <<" expected non-datatype "<<side
+                            <<" but '"<<underp->name()<<"' is a datatype.");
         } else {
             AstBasicDType* expBasicp = expDTypep->basicp();
             AstBasicDType* underBasicp = underp->dtypep()->basicp();
diff --git a/test_regress/t/t_param_type_bad.out b/test_regress/t/t_param_type_bad.out
new file mode 100644
index 000000000..269e88619
--- /dev/null
+++ b/test_regress/t/t_param_type_bad.out
@@ -0,0 +1,4 @@
+%Error: t/t_param_type_bad.v:8: Parameter type's initial value isn't a type: 'bad2'
+   localparam type bad2 = 2;   
+                   ^~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_param_type_bad.pl b/test_regress/t/t_param_type_bad.pl
new file mode 100755
index 000000000..ef912260b
--- /dev/null
+++ b/test_regress/t/t_param_type_bad.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+scenarios(vlt => 1);
+
+lint(
+    # Bug1575 required trace to crash
+    verilator_flags2 => ["--trace"],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_param_type_bad.v b/test_regress/t/t_param_type_bad.v
new file mode 100644
index 000000000..686f415c4
--- /dev/null
+++ b/test_regress/t/t_param_type_bad.v
@@ -0,0 +1,9 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2019 by Wilson Snyder.
+
+module t;
+   localparam type t = logic;  // Fine
+   localparam type bad2 = 2;  // Bad
+endmodule
diff --git a/test_regress/t/t_param_type_bad2.out b/test_regress/t/t_param_type_bad2.out
new file mode 100644
index 000000000..fa74f0304
--- /dev/null
+++ b/test_regress/t/t_param_type_bad2.out
@@ -0,0 +1,4 @@
+%Error: t/t_param_type_bad2.v:8: Parameter type's initial value isn't a type: 'bad2'
+   localparam type bad2 = 2;   
+                   ^~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_param_type_bad2.pl b/test_regress/t/t_param_type_bad2.pl
new file mode 100755
index 000000000..ef912260b
--- /dev/null
+++ b/test_regress/t/t_param_type_bad2.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+scenarios(vlt => 1);
+
+lint(
+    # Bug1575 required trace to crash
+    verilator_flags2 => ["--trace"],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_param_type_bad2.v b/test_regress/t/t_param_type_bad2.v
new file mode 100644
index 000000000..686f415c4
--- /dev/null
+++ b/test_regress/t/t_param_type_bad2.v
@@ -0,0 +1,9 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2019 by Wilson Snyder.
+
+module t;
+   localparam type t = logic;  // Fine
+   localparam type bad2 = 2;  // Bad
+endmodule