diff --git a/vlib/v/checker/assign.v b/vlib/v/checker/assign.v
index 3553cba664..1e9cd936d1 100644
--- a/vlib/v/checker/assign.v
+++ b/vlib/v/checker/assign.v
@@ -355,6 +355,9 @@ fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 								c.warn('duplicate of a const name `${full_name}`', left.pos)
 							}
 						}
+						if left.mod == left.name && !c.file.path.contains('vlib') {
+							c.error('duplicate of an module name `${left.name}`', left.pos)
+						}
 						// Check if variable name is already registered as imported module symbol
 						if c.check_import_sym_conflict(left.name) {
 							c.error('duplicate of an import symbol `${left.name}`', left.pos)
diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index 1780668ec3..4593de5c44 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -256,11 +256,17 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 					}
 				}
 			}
+			if node.mod == param.name && !c.file.path.contains('vlib') {
+				c.error('duplicate of an module name `${param.name}`', param.pos)
+			}
 			// Check if parameter name is already registered as imported module symbol
 			if c.check_import_sym_conflict(param.name) {
 				c.error('duplicate of an import symbol `${param.name}`', param.pos)
 			}
 		}
+		if node.mod == node.short_name && !c.file.path.contains('vlib') && node.mod != 'main' {
+			c.error('duplicate of an module name `${node.short_name}`', node.pos)
+		}
 		// Check if function name is already registered as imported module symbol
 		if !node.is_method && c.check_import_sym_conflict(node.short_name) {
 			c.error('duplicate of an import symbol `${node.short_name}`', node.pos)