diff --git a/Changes b/Changes
index 79495183c..cc83c659d 100644
--- a/Changes
+++ b/Changes
@@ -16,6 +16,8 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 ****  Fix multithreaded yield behavior when no work.  [Patrick Stewart]
 
+****  Fix misc bad-syntax crashes, bug1548, bug1550-1553. [Eric Rippey]
+
 
 * Verilator 4.020 2019-10-06
 
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index c0b53eab5..f1c3a120a 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -1125,8 +1125,8 @@ class LinkDotFindVisitor : public AstNVisitor {
                 && !foundp->imported()) {  // and not from package
                 nodep->v3error("Duplicate declaration of enum value: "<<nodep->prettyName()<<endl
                                <<nodep->warnContextPrimary()<<endl
-                               <<findvarp->warnOther()<<"... Location of original declaration\n"
-                               <<findvarp->warnContextSecondary());
+                               <<foundp->nodep()->warnOther()<<"... Location of original declaration\n"
+                               <<foundp->nodep()->warnContextSecondary());
             } else {
                 // User can disable the message at either point
                 if (!nodep->fileline()->warnIsOff(V3ErrorCode::VARHIDDEN)
diff --git a/src/V3PreProc.cpp b/src/V3PreProc.cpp
index 249f73821..51e490286 100644
--- a/src/V3PreProc.cpp
+++ b/src/V3PreProc.cpp
@@ -136,6 +136,7 @@ public:
 
     std::stack<ProcState> m_states;  ///< Current state of parser
     int         m_off;          ///< If non-zero, ifdef level is turned off, don't dump text
+    bool        m_incError;     ///< Include error found
     string      m_lastSym;      ///< Last symbol name found.
     string      m_formals;      ///< Last formals found
 
@@ -250,6 +251,7 @@ public:
         m_debug = 0;
         m_states.push(ps_TOP);
         m_off = 0;
+        m_incError = false;
         m_lineChars = "";
         m_lastSym = "";
         m_lineAdd = 0;
@@ -748,6 +750,7 @@ string V3PreProcImp::defineSubst(VDefineRef* refp) {
 
 void V3PreProcImp::openFile(FileLine* fl, VInFilter* filterp, const string& filename) {
     // Open a new file, possibly overriding the current one which is active.
+    if (m_incError) return;
     V3File::addSrcDepend(filename);
 
     // Read a list<string> with the whole file.
@@ -761,8 +764,11 @@ void V3PreProcImp::openFile(FileLine* fl, VInFilter* filterp, const string& file
     if (!m_preprocp->isEof()) {  // IE not the first file.
         // We allow the same include file twice, because occasionally it pops
         // up, with guards preventing a real recursion.
-        if (m_lexp->m_streampStack.size()>V3PreProc::INCLUDE_DEPTH_MAX) {
+        if (m_lexp->m_streampStack.size() > V3PreProc::INCLUDE_DEPTH_MAX) {
             error("Recursive inclusion of file: "+filename);
+            // Include might be a tree of includes that is O(n^2) or worse.
+            // Once hit this error then, ignore all further includes so can unwind.
+            m_incError = true;
             return;
         }
         // There's already a file active.  Push it to work on the new one.
diff --git a/src/verilog.y b/src/verilog.y
index d7f1f9bd3..b2f3bdab6 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -1125,7 +1125,7 @@ anonymous_program_item<nodep>:	// ==IEEE: anonymous_program_item
 	//UNSUP	class_declaration			{ $$ = $1; }
 	//UNSUP	covergroup_declaration			{ $$ = $1; }
 	//			// class_constructor_declaration is part of function_declaration
-	|	';'					{ }
+	|	';'					{ $$ = NULL; }
 	;
 
 program_declaration:		// IEEE: program_declaration + program_nonansi_header + program_ansi_header:
@@ -3400,7 +3400,7 @@ exprOkLvalue<nodep>:		// expression that's also OK to use as a variable_lvalue
 	//			// IEEE: [ assignment_pattern_expression_type ] == [ ps_type_id /ps_paremeter_id/data_type]
 	//			// We allow more here than the spec requires
 	//UNSUP	~l~exprScope assignment_pattern		{ UNSUP }
-	|	data_type assignment_pattern		{ $$ = $2; $2->childDTypep($1); }
+	|	data_type assignment_pattern		{ $$ = $2; if ($2) $2->childDTypep($1); }
 	|	assignment_pattern			{ $$ = $1; }
 	//
 	|	streaming_concatenation			{ $$ = $1; }
@@ -3749,7 +3749,7 @@ combinational_body<nodep>:	// IEEE: combinational_body + sequential_body
 
 tableEntryList<nodep>:	// IEEE: { combinational_entry | sequential_entry }
 		tableEntry 				{ $$ = $1; }
-	|	tableEntryList tableEntry		{ $$ = $1->addNext($2); }
+	|	tableEntryList tableEntry		{ $$ = $1->addNextNull($2); }
 	;
 
 tableEntry<nodep>:	// IEEE: combinational_entry + sequential_entry
diff --git a/test_regress/t/t_preproc_inc_recurse_bad.out b/test_regress/t/t_preproc_inc_recurse_bad.out
new file mode 100644
index 000000000..a4ac2808b
--- /dev/null
+++ b/test_regress/t/t_preproc_inc_recurse_bad.out
@@ -0,0 +1,4 @@
+%Error: t/t_preproc_inc_recurse_bad.v:6: Recursive inclusion of file: t/t_preproc_inc_recurse_bad.v
+`include "t_preproc_inc_recurse_bad.v"
+         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_preproc_inc_recurse_bad.pl b/test_regress/t/t_preproc_inc_recurse_bad.pl
new file mode 100755
index 000000000..b09f43e8b
--- /dev/null
+++ b/test_regress/t/t_preproc_inc_recurse_bad.pl
@@ -0,0 +1,18 @@
+#!/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(linter => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_preproc_inc_recurse_bad.v b/test_regress/t/t_preproc_inc_recurse_bad.v
new file mode 100644
index 000000000..da097aeaf
--- /dev/null
+++ b/test_regress/t/t_preproc_inc_recurse_bad.v
@@ -0,0 +1,6 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2019 by Wilson Snyder.
+
+`include "t_preproc_inc_recurse_bad.v"