Rollup merge of #61856 - c410-f3r:attrs-fn, r=matthewjasper

Lint attributes on function arguments

Fixes #61238.

cc #60406

6 files changed, 23 insertions, 8 deletions

diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index a7453f4f9da..58a1c4aee9a 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1796,6 +1796,7 @@ pub struct Arg {
     pub ty: P<Ty>,
     pub pat: P<Pat>,
     pub id: NodeId,
+    pub span: Span,
 }
 
 /// Alternative representation for `Arg`s describing `self` parameter of methods.
@@ -1854,6 +1855,7 @@ impl Arg {
                 node: PatKind::Ident(BindingMode::ByValue(mutbl), eself_ident, None),
                 span,
             }),
+            span,
             ty,
             id: DUMMY_NODE_ID,
         };
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 528b27d6153..b30fefe5b96 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -966,6 +966,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             attrs: ThinVec::default(),
             id: ast::DUMMY_NODE_ID,
             pat: arg_pat,
+            span,
             ty,
         }
     }
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
index 86525406718..43b6bea69d9 100644
--- a/src/libsyntax/mut_visit.rs
+++ b/src/libsyntax/mut_visit.rs
@@ -558,10 +558,11 @@ pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
     vis.visit_span(span);
 }
 
-pub fn noop_visit_arg<T: MutVisitor>(Arg { attrs, id, pat, ty }: &mut Arg, vis: &mut T) {
+pub fn noop_visit_arg<T: MutVisitor>(Arg { attrs, id, pat, span, ty }: &mut Arg, vis: &mut T) {
     vis.visit_id(id);
     visit_thin_attrs(attrs, vis);
     vis.visit_pat(pat);
+    vis.visit_span(span);
     vis.visit_ty(ty);
 }
 
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs
index f4fc87506f3..39cb5042fbc 100644
--- a/src/libsyntax/parse/diagnostics.rs
+++ b/src/libsyntax/parse/diagnostics.rs
@@ -30,7 +30,7 @@ crate fn dummy_arg(ident: Ident) -> Arg {
         span: ident.span,
         id: ast::DUMMY_NODE_ID
     };
-    Arg { attrs: ThinVec::default(), id: ast::DUMMY_NODE_ID, pat, ty: P(ty) }
+    Arg { attrs: ThinVec::default(), id: ast::DUMMY_NODE_ID, pat, span: ident.span, ty: P(ty) }
 }
 
 pub enum Error {
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 8f8ed411180..6cb965bf817 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1515,6 +1515,7 @@ impl<'a> Parser<'a> {
     where
         F: Fn(&token::Token) -> bool
     {
+        let lo = self.token.span;
         let attrs = self.parse_arg_attributes()?;
         if let Some(mut arg) = self.parse_self_arg()? {
             arg.attrs = attrs.into();
@@ -1578,11 +1579,14 @@ impl<'a> Parser<'a> {
             }
         };
 
-        Ok(Arg { attrs: attrs.into(), id: ast::DUMMY_NODE_ID, pat, ty })
+        let span = lo.to(self.token.span);
+
+        Ok(Arg { attrs: attrs.into(), id: ast::DUMMY_NODE_ID, pat, span, ty })
     }
 
     /// Parses an argument in a lambda header (e.g., `|arg, arg|`).
     fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
+        let lo = self.token.span;
         let attrs = self.parse_arg_attributes()?;
         let pat = self.parse_pat(Some("argument name"))?;
         let t = if self.eat(&token::Colon) {
@@ -1594,10 +1598,12 @@ impl<'a> Parser<'a> {
                 span: self.prev_span,
             })
         };
+        let span = lo.to(self.token.span);
         Ok(Arg {
             attrs: attrs.into(),
             ty: t,
             pat,
+            span,
             id: ast::DUMMY_NODE_ID
         })
     }
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index ff6440fb9dc..50be8c68f7f 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -66,6 +66,7 @@ pub trait Visitor<'ast>: Sized {
     fn visit_local(&mut self, l: &'ast Local) { walk_local(self, l) }
     fn visit_block(&mut self, b: &'ast Block) { walk_block(self, b) }
     fn visit_stmt(&mut self, s: &'ast Stmt) { walk_stmt(self, s) }
+    fn visit_arg(&mut self, arg: &'ast Arg) { walk_arg(self, arg) }
     fn visit_arm(&mut self, a: &'ast Arm) { walk_arm(self, a) }
     fn visit_pat(&mut self, p: &'ast Pat) { walk_pat(self, p) }
     fn visit_anon_const(&mut self, c: &'ast AnonConst) { walk_anon_const(self, c) }
@@ -547,12 +548,10 @@ pub fn walk_fn_ret_ty<'a, V: Visitor<'a>>(visitor: &mut V, ret_ty: &'a FunctionR
 }
 
 pub fn walk_fn_decl<'a, V: Visitor<'a>>(visitor: &mut V, function_declaration: &'a FnDecl) {
-    for argument in &function_declaration.inputs {
-        walk_list!(visitor, visit_attribute, argument.attrs.iter());
-        visitor.visit_pat(&argument.pat);
-        visitor.visit_ty(&argument.ty);
+    for arg in &function_declaration.inputs {
+        visitor.visit_arg(arg);
     }
-    visitor.visit_fn_ret_ty(&function_declaration.output)
+    visitor.visit_fn_ret_ty(&function_declaration.output);
 }
 
 pub fn walk_fn<'a, V>(visitor: &mut V, kind: FnKind<'a>, declaration: &'a FnDecl, _span: Span)
@@ -822,6 +821,12 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
     visitor.visit_expr_post(expression)
 }
 
+pub fn walk_arg<'a, V: Visitor<'a>>(visitor: &mut V, arg: &'a Arg) {
+    walk_list!(visitor, visit_attribute, arg.attrs.iter());
+    visitor.visit_pat(&arg.pat);
+    visitor.visit_ty(&arg.ty);
+}
+
 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
     walk_list!(visitor, visit_pat, &arm.pats);
     if let Some(ref e) = &arm.guard {