From 523d1e2166ebb5b2b8ea98058a72056f37551d52 Mon Sep 17 00:00:00 2001
From: Luca Casonato <hello@lcas.dev>
Date: Thu, 11 Apr 2024 21:56:01 +0200
Subject: [PATCH] fix(fast_check): properly handle rest parameters in overloads
 (#432)

---
 src/fast_check/transform.rs                   |  42 ++++++--
 tests/specs/graph/jsr/FastCheck_Overloads.txt | 101 ++++++++++++++++++
 2 files changed, 132 insertions(+), 11 deletions(-)
 create mode 100644 tests/specs/graph/jsr/FastCheck_Overloads.txt

diff --git a/src/fast_check/transform.rs b/src/fast_check/transform.rs
index d2db747b8..dd009ad0b 100644
--- a/src/fast_check/transform.rs
+++ b/src/fast_check/transform.rs
@@ -911,18 +911,38 @@ impl<'a> FastCheckTransformer<'a> {
     }
     if is_overload {
       for (i, param) in n.params.iter_mut().enumerate() {
-        *param = Param {
-          span: DUMMY_SP,
-          decorators: Vec::new(),
-          pat: Pat::Ident(BindingIdent {
-            id: Ident {
+        if param.pat.is_rest() {
+          *param = Param {
+            span: DUMMY_SP,
+            decorators: Vec::new(),
+            pat: Pat::Rest(RestPat {
               span: DUMMY_SP,
-              sym: format!("param{}", i).into(),
-              optional: true,
-            },
-            type_ann: Some(any_type_ann()),
-          }),
-        };
+              dot3_token: DUMMY_SP,
+              type_ann: Some(any_type_ann()),
+              arg: Box::new(Pat::Ident(BindingIdent {
+                id: Ident {
+                  span: DUMMY_SP,
+                  sym: format!("param{}", i).into(),
+                  optional: true,
+                },
+                type_ann: None,
+              })),
+            }),
+          };
+        } else {
+          *param = Param {
+            span: DUMMY_SP,
+            decorators: Vec::new(),
+            pat: Pat::Ident(BindingIdent {
+              id: Ident {
+                span: DUMMY_SP,
+                sym: format!("param{}", i).into(),
+                optional: true,
+              },
+              type_ann: Some(any_type_ann()),
+            }),
+          };
+        }
       }
       n.return_type = Some(any_type_ann());
     }
diff --git a/tests/specs/graph/jsr/FastCheck_Overloads.txt b/tests/specs/graph/jsr/FastCheck_Overloads.txt
new file mode 100644
index 000000000..b34053113
--- /dev/null
+++ b/tests/specs/graph/jsr/FastCheck_Overloads.txt
@@ -0,0 +1,101 @@
+# https://jsr.io/@scope/a/meta.json
+{"versions": { "1.0.0": {} } }
+
+# https://jsr.io/@scope/a/1.0.0_meta.json
+{ "exports": { ".": "./mod.ts" } }
+
+# https://jsr.io/@scope/a/1.0.0/mod.ts
+export class argsToArray {
+  argsToArray(..._args: string[]): void;
+  argsToArray(..._args: number[]): void;
+  argsToArray(..._args: unknown[]): void {}
+}
+
+export function overloadSpread(...args: string[]);
+export function overloadSpread(...args: number[]);
+export function overloadSpread(...args: unknown[]) {
+  return args;
+}
+
+export function overloadLast(value: string, ...args: string[]);
+export function overloadLast(value: number, ...args: number[]);
+export function overloadLast(value: string | number, ...args: unknown[]) {
+  return args;
+}
+
+# mod.ts
+import 'jsr:@scope/a'
+
+# output
+{
+  "roots": [
+    "file:///mod.ts"
+  ],
+  "modules": [
+    {
+      "kind": "esm",
+      "dependencies": [
+        {
+          "specifier": "jsr:@scope/a",
+          "code": {
+            "specifier": "jsr:@scope/a",
+            "span": {
+              "start": {
+                "line": 0,
+                "character": 7
+              },
+              "end": {
+                "line": 0,
+                "character": 21
+              }
+            }
+          }
+        }
+      ],
+      "size": 22,
+      "mediaType": "TypeScript",
+      "specifier": "file:///mod.ts"
+    },
+    {
+      "kind": "esm",
+      "size": 549,
+      "mediaType": "TypeScript",
+      "specifier": "https://jsr.io/@scope/a/1.0.0/mod.ts"
+    }
+  ],
+  "redirects": {
+    "jsr:@scope/a": "https://jsr.io/@scope/a/1.0.0/mod.ts"
+  },
+  "packages": {
+    "@scope/a": "@scope/a@1.0.0"
+  }
+}
+
+Fast check https://jsr.io/@scope/a/1.0.0/mod.ts:
+  {}
+  export class argsToArray {
+    argsToArray(..._args: string[]): void;
+    argsToArray(..._args: number[]): void;
+    argsToArray(...param0?: any): any {
+      return {} as never;
+    }
+  }
+  export function overloadSpread(...args: string[]);
+  export function overloadSpread(...args: number[]);
+  export function overloadSpread(...param0?: any): any {
+    return {} as never;
+  }
+  export function overloadLast(value: string, ...args: string[]);
+  export function overloadLast(value: number, ...args: number[]);
+  export function overloadLast(param0?: any, ...param1?: any): any {
+    return {} as never;
+  }
+  --- DTS ---
+  export declare class argsToArray {
+    argsToArray(..._args: string[]): void;
+    argsToArray(..._args: number[]): void;
+  }
+  export declare function overloadSpread(...args: string[]);
+  export declare function overloadSpread(...args: number[]);
+  export declare function overloadLast(value: string, ...args: string[]);
+  export declare function overloadLast(value: number, ...args: number[]);