diff --git a/Makefile b/Makefile
index a6f4235d7..4a966a5c7 100644
--- a/Makefile
+++ b/Makefile
@@ -176,7 +176,7 @@ ifeq ($(OS), Haiku)
 CXXFLAGS += -D_DEFAULT_SOURCE
 endif
 
-YOSYS_VER := 0.52+137
+YOSYS_VER := 0.52+139
 YOSYS_MAJOR := $(shell echo $(YOSYS_VER) | cut -d'.' -f1)
 YOSYS_MINOR := $(shell echo $(YOSYS_VER) | cut -d'.' -f2)
 YOSYS_COMMIT := $(shell echo $(YOSYS_VER) | cut -d'.' -f3)
diff --git a/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h b/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h
index 886d033cb..9b4f5774f 100644
--- a/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h
+++ b/backends/cxxrtl/runtime/cxxrtl/cxxrtl.h
@@ -1769,7 +1769,7 @@ value<BitsY> shr_uu(const value<BitsA> &a, const value<BitsB> &b) {
 template<size_t BitsY, size_t BitsA, size_t BitsB>
 CXXRTL_ALWAYS_INLINE
 value<BitsY> shr_su(const value<BitsA> &a, const value<BitsB> &b) {
-	return a.shr(b).template scast<BitsY>();
+	return a.template scast<BitsY>().shr(b);
 }
 
 template<size_t BitsY, size_t BitsA, size_t BitsB>
diff --git a/frontends/verilog/verilog_parser.y b/frontends/verilog/verilog_parser.y
index fe86626b8..9d0956c8e 100644
--- a/frontends/verilog/verilog_parser.y
+++ b/frontends/verilog/verilog_parser.y
@@ -2249,7 +2249,8 @@ cell_parameter:
 		node->children.push_back($1);
 	} |
 	'.' TOK_ID '(' ')' {
-		// just ignore empty parameters
+		// delete unused TOK_ID
+		delete $2;
 	} |
 	'.' TOK_ID '(' expr ')' {
 		AstNode *node = new AstNode(AST_PARASET);
diff --git a/tests/verilog/param_default.ys b/tests/verilog/param_default.ys
new file mode 100644
index 000000000..59023c477
--- /dev/null
+++ b/tests/verilog/param_default.ys
@@ -0,0 +1,24 @@
+logger -expect-no-warnings
+read_verilog << EOF
+module bar (
+	input portname
+);
+	parameter paramname = 7;
+endmodule
+ 
+module empty (
+);
+ 	bar #() barinstance ();
+endmodule
+
+module implicit (
+);
+ 	bar #(.paramname()) barinstance (.portname());
+endmodule
+
+module explicit (
+	input a
+);
+	bar #(.paramname(3)) barinstance (.portname(a));
+endmodule
+EOF