diff --git a/lang/semgrep-grammars/src/semgrep-swift/grammar.js b/lang/semgrep-grammars/src/semgrep-swift/grammar.js
index 743b7dda..3b5276ee 100644
--- a/lang/semgrep-grammars/src/semgrep-swift/grammar.js
+++ b/lang/semgrep-grammars/src/semgrep-swift/grammar.js
@@ -83,5 +83,11 @@ module.exports = grammar(base_grammar, {
         field("suffix", $.semgrep_ellipsis),
       ),
     ),
+
+    parameter: ($, previous) => choice (
+      previous,
+      $.semgrep_ellipsis,
+      $.semgrep_ellipsis_metavar
+    )
   }
 });
diff --git a/lang/semgrep-grammars/src/semgrep-swift/test/corpus/semgrep.txt b/lang/semgrep-grammars/src/semgrep-swift/test/corpus/semgrep.txt
index 5b483312..f55c958a 100644
--- a/lang/semgrep-grammars/src/semgrep-swift/test/corpus/semgrep.txt
+++ b/lang/semgrep-grammars/src/semgrep-swift/test/corpus/semgrep.txt
@@ -21,9 +21,60 @@ Unbounded range operator
 
 (source_file
   (additive_expression
-    (tuple_expression (fully_open_range))
+    (tuple_expression
+      (fully_open_range))
     (integer_literal)))
 
+================================================================================
+Parameter Ellipsis
+================================================================================
+
+func $F(..., $X: $T, ...) {
+  ...
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (function_declaration
+    (simple_identifier)
+    (parameter
+      (semgrep_ellipsis))
+    (parameter
+      (simple_identifier)
+      (user_type
+        (type_identifier)))
+    (parameter
+      (semgrep_ellipsis))
+    (function_body
+      (statements
+        (fully_open_range)))))
+
+================================================================================
+Parameter Metavariable Ellipsis
+================================================================================
+
+func $F($...ARGS1, $X: $T, $...ARGS2) {
+  ...
+}
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (function_declaration
+    (simple_identifier)
+    (parameter
+      (semgrep_ellipsis_metavar))
+    (parameter
+      (simple_identifier)
+      (user_type
+        (type_identifier)))
+    (parameter
+      (semgrep_ellipsis_metavar))
+    (function_body
+      (statements
+        (fully_open_range)))))
+
 ================================================================================
 Argument Ellipsis
 ================================================================================
@@ -37,14 +88,19 @@ foo(..., 1, ...);
   (call_expression
     (simple_identifier)
     (call_suffix
-      (value_arguments (value_argument (fully_open_range)))))
+      (value_arguments
+        (value_argument
+          (fully_open_range)))))
   (call_expression
     (simple_identifier)
     (call_suffix
       (value_arguments
-        (value_argument (fully_open_range))
-        (value_argument (integer_literal))
-        (value_argument (fully_open_range))))))
+        (value_argument
+          (fully_open_range))
+        (value_argument
+          (integer_literal))
+        (value_argument
+          (fully_open_range))))))
 
 ================================================================================
 Ellipsis Metavariable
@@ -60,14 +116,19 @@ $...FOO + 1;
   (call_expression
     (simple_identifier)
     (call_suffix
-      (value_arguments (value_argument (semgrep_ellipsis_metavar)))))
+      (value_arguments
+        (value_argument
+          (semgrep_ellipsis_metavar)))))
   (call_expression
     (simple_identifier)
     (call_suffix
       (value_arguments
-        (value_argument (semgrep_ellipsis_metavar))
-        (value_argument (integer_literal))
-        (value_argument (semgrep_ellipsis_metavar)))))
+        (value_argument
+          (semgrep_ellipsis_metavar))
+        (value_argument
+          (integer_literal))
+        (value_argument
+          (semgrep_ellipsis_metavar)))))
   (additive_expression
     (semgrep_ellipsis_metavar)
     (integer_literal)))
@@ -98,13 +159,16 @@ func foo<T, ...>() { }
   (function_declaration
     (simple_identifier)
     (type_parameters
-      (type_parameter (semgrep_ellipsis)))
+      (type_parameter
+        (semgrep_ellipsis)))
     (function_body))
   (function_declaration
     (simple_identifier)
     (type_parameters
-      (type_parameter (type_identifier))
-      (type_parameter (semgrep_ellipsis)))
+      (type_parameter
+        (type_identifier))
+      (type_parameter
+        (semgrep_ellipsis)))
     (function_body)))
 
 ================================================================================
@@ -115,7 +179,10 @@ Deep Ellipsis
 
 --------------------------------------------------------------------------------
 
-(source_file (semgrep_deep_ellipsis (integer_literal) (custom_operator)))
+(source_file
+  (semgrep_deep_ellipsis
+    (integer_literal)
+    (custom_operator)))
 
 ================================================================================
 Deep Ellipsis with custom operator (should not parse, but does because of a hack
@@ -126,7 +193,10 @@ necessary to work around custom operators getting scanned by the custom scanner)
 
 --------------------------------------------------------------------------------
 
-(source_file (semgrep_deep_ellipsis (integer_literal) (custom_operator)))
+(source_file
+  (semgrep_deep_ellipsis
+    (integer_literal)
+    (custom_operator)))
 
 ================================================================================
 Deep Ellipsis with custom operator (this parses due to parens)
@@ -155,10 +225,14 @@ class ClassName {
 
 --------------------------------------------------------------------------------
 
-(source_file (class_declaration (type_identifier) (class_body (semgrep_ellipsis))))
+(source_file
+  (class_declaration
+    (type_identifier)
+    (class_body
+      (semgrep_ellipsis))))
 
 ================================================================================
-Class Ellipsis Sandwiched 
+Class Ellipsis Sandwiched
 ================================================================================
 
 class ClassName {
@@ -169,7 +243,17 @@ class ClassName {
 
 --------------------------------------------------------------------------------
 
-(source_file (class_declaration (type_identifier) (class_body (semgrep_ellipsis) (property_declaration (value_binding_pattern) (pattern (simple_identifier)) (integer_literal)) (semgrep_ellipsis))))
+(source_file
+  (class_declaration
+    (type_identifier)
+    (class_body
+      (semgrep_ellipsis)
+      (property_declaration
+        (value_binding_pattern)
+        (pattern
+          (simple_identifier))
+        (integer_literal))
+      (semgrep_ellipsis))))
 
 ================================================================================
 Statement Ellipsis with semicolon