diff --git a/frontends/ast/ast.h b/frontends/ast/ast.h
index 9887d24ea..b6b15b738 100644
--- a/frontends/ast/ast.h
+++ b/frontends/ast/ast.h
@@ -326,6 +326,9 @@ namespace AST
 
 		// helpers for locations
 		std::string loc_string() const;
+
+		// Helper for looking up identifiers which are prefixed with the current module name
+		std::string try_pop_module_prefix() const;
 	};
 
 	// process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code
diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index b8b9f715e..e886844be 100644
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -767,8 +767,15 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
 
 	case AST_IDENTIFIER:
 		id_ast = id2ast;
-		if (id_ast == NULL && current_scope.count(str))
-			id_ast = current_scope.at(str);
+		if (!id_ast) {
+			if (current_scope.count(str))
+				id_ast = current_scope[str];
+			else {
+				std::string alt = try_pop_module_prefix();
+				if (current_scope.count(alt))
+					id_ast = current_scope[alt];
+			}
+		}
 		if (!id_ast)
 			log_file_error(filename, location.first_line, "Failed to resolve identifier %s for width detection!\n", str.c_str());
 		if (id_ast->type == AST_PARAMETER || id_ast->type == AST_LOCALPARAM || id_ast->type == AST_ENUM_ITEM) {
diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 44b11da74..cd27a720a 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -1698,17 +1698,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
 	if (type == AST_IDENTIFIER) {
 		if (current_scope.count(str) == 0) {
 			AstNode *current_scope_ast = (current_ast_mod == nullptr) ? current_ast : current_ast_mod;
-			size_t pos = str.find('.', 1);
-			if (str[0] == '\\' && pos != std::string::npos) {
-				std::string new_str = "\\" + str.substr(pos + 1);
-				if (current_scope.count(new_str)) {
-					std::string prefix = str.substr(0, pos);
-					auto it = current_scope_ast->attributes.find(ID::hdlname);
-					if ((it != current_scope_ast->attributes.end() && it->second->str == prefix)
-							|| prefix == current_scope_ast->str)
-						str = new_str;
-				}
-			}
+			str = try_pop_module_prefix();
 			for (auto node : current_scope_ast->children) {
 				//log("looking at mod scope child %s\n", type2str(node->type).c_str());
 				switch (node->type) {
@@ -5124,4 +5114,21 @@ std::pair<AstNode*, AstNode*> AstNode::get_tern_choice()
 	return {choice, not_choice};
 }
 
+std::string AstNode::try_pop_module_prefix() const
+{
+	AstNode *current_scope_ast = (current_ast_mod == nullptr) ? current_ast : current_ast_mod;
+	size_t pos = str.find('.', 1);
+	if (str[0] == '\\' && pos != std::string::npos) {
+		std::string new_str = "\\" + str.substr(pos + 1);
+		if (current_scope.count(new_str)) {
+			std::string prefix = str.substr(0, pos);
+			auto it = current_scope_ast->attributes.find(ID::hdlname);
+			if ((it != current_scope_ast->attributes.end() && it->second->str == prefix)
+					|| prefix == current_scope_ast->str)
+				return new_str;
+		}
+	}
+	return str;
+}
+
 YOSYS_NAMESPACE_END
diff --git a/tests/simple/module_scope_case.v b/tests/simple/module_scope_case.v
new file mode 100644
index 000000000..1472b6912
--- /dev/null
+++ b/tests/simple/module_scope_case.v
@@ -0,0 +1,11 @@
+module top(
+	input wire x,
+	output reg y
+);
+	always @* begin
+		case (top.x)
+			1: top.y = 0;
+			0: top.y = 1;
+		endcase
+	end
+endmodule