fix(es/minifier): Set param type to unknown

crates/swc_ecma_minifier/src/program_data.rs

@@ -449,7 +449,12 @@ impl Storage for ProgramData {
         }
 
         v.var_initialized |= init_type.is_some();
-        v.merged_var_type.merge(init_type);
+
+        if ctx.in_pat_of_param {
+            v.merged_var_type = Some(Value::Unknown);
+        } else {
+            v.merged_var_type.merge(init_type);
+        }
 
         v.declared_count += 1;
         v.declared = true;

crates/swc_ecma_minifier/tests/fixture/issues/8718/7/input.js

@@ -0,0 +1,6 @@
+export function foo(a) {
+    a += 1;
+    a += 2;
+
+    return a;
+}

crates/swc_ecma_minifier/tests/fixture/issues/8718/7/output.js

@@ -0,0 +1,3 @@
+export function foo(a) {
+    return a += 1, a += 2;
+}