Omit warning only for first parameter named self, to scope impact

third_party/move/move-compiler-v2/tests/checking/receiver/dont_warn_unused_self.exp

@@ -1,9 +1,17 @@
+
+Diagnostics:
+warning: Unused parameter `y`. Consider removing or prefixing with an underscore: `_y`
+  ┌─ tests/checking/receiver/dont_warn_unused_self.move:5:27
+  │
+5 │     fun receiver(self: S, y: u64) {
+  │                           ^
+
 // -- Model dump before bytecode pipeline
 module 0x42::m {
     struct S {
         x: u64,
     }
-    private fun receiver(self: m::S,_y: u64) {
+    private fun receiver(self: m::S,y: u64) {
         Tuple()
     }
     spec {

third_party/move/move-compiler-v2/tests/checking/receiver/dont_warn_unused_self.move

@@ -2,10 +2,10 @@ module 0x42::m {
 
     struct S has drop { x: u64 }
 
-    fun receiver(self: S, _y: u64) {
+    fun receiver(self: S, y: u64) {
     }
 
-    spec receiver(self: S, _y: u64) {
+    spec receiver(self: S, y: u64) {
         requires true;
     }
 }

third_party/move/move-compiler/src/hlir/ast.rs

@@ -371,6 +371,13 @@ impl FunctionSignature {
             .iter()
             .any(|(parameter_name, _)| parameter_name == v)
     }
+
+    pub fn is_first_parameter(&self, v: &Var) -> bool {
+        self.parameters
+            .first()
+            .map(|(parameter_name, _)| parameter_name == v)
+            .unwrap_or(false)
+    }
 }
 
 impl Command_ {

third_party/move/move-compiler/src/hlir/translate.rs

@@ -1972,7 +1972,7 @@ fn check_unused_locals(
             DisplayVar::Tmp => panic!("ICE unused tmp"),
             DisplayVar::Orig(vstr) => vstr,
         };
-        if signature.is_parameter(&v) && vstr == "self" {
+        if signature.is_first_parameter(&v) && vstr == "self" {
             // Special treatment for `self` Move 2 parameter: do not warn if unused
             // for the case v1 compiles v2 code
             continue;

third_party/move/move-compiler/tests/move_check/locals/dont_warn_unused_self.exp

@@ -0,0 +1,6 @@
+warning[W09002]: unused variable
+  ┌─ tests/move_check/locals/dont_warn_unused_self.move:5:27
+  │
+5 │     fun receiver(self: S, y: u64) {
+  │                           ^ Unused parameter 'y'. Consider removing or prefixing with an underscore: '_y'
+

third_party/move/move-compiler/tests/move_check/locals/dont_warn_unused_self.move

@@ -2,10 +2,10 @@ module 0x42::m {
 
     struct S has drop { x: u64 }
 
-    fun receiver(self: S, _y: u64) {
+    fun receiver(self: S, y: u64) {
     }
 
-    spec receiver(self: S, _y: u64) {
+    spec receiver(self: S, y: u64) {
         requires true;
     }
 }