Do not consider method call receiver as an argument in AST.

Author: cjgillot

clippy_lints/src/double_parens.rs

@@ -61,9 +61,8 @@ impl EarlyLintPass for DoubleParens {
                     }
                 }
             },
-            ExprKind::MethodCall(_, ref params, _) => {
-                if params.len() == 2 {
-                    let param = &params[1];
+            ExprKind::MethodCall(_, _, ref params, _) => {
+                if let [ref param] = params[..] {
                     if let ExprKind::Paren(_) = param.kind {
                         span_lint(cx, DOUBLE_PARENS, param.span, msg);
                     }

clippy_lints/src/option_env_unwrap.rs

@@ -37,9 +37,9 @@ declare_lint_pass!(OptionEnvUnwrap => [OPTION_ENV_UNWRAP]);
 impl EarlyLintPass for OptionEnvUnwrap {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
         if_chain! {
-            if let ExprKind::MethodCall(path_segment, args, _) = &expr.kind;
+            if let ExprKind::MethodCall(path_segment, receiver, _, _) = &expr.kind;
             if matches!(path_segment.ident.name, sym::expect | sym::unwrap);
-            if let ExprKind::Call(caller, _) = &args[0].kind;
+            if let ExprKind::Call(caller, _) = &receiver.kind;
             if is_direct_expn_of(caller.span, "option_env").is_some();
             then {
                 span_lint_and_help(

clippy_lints/src/precedence.rs

@@ -109,12 +109,12 @@ impl EarlyLintPass for Precedence {
             let mut arg = operand;
 
             let mut all_odd = true;
-            while let ExprKind::MethodCall(path_segment, args, _) = &arg.kind {
+            while let ExprKind::MethodCall(path_segment, receiver, _, _) = &arg.kind {
                 let path_segment_str = path_segment.ident.name.as_str();
                 all_odd &= ALLOWED_ODD_FUNCTIONS
                     .iter()
                     .any(|odd_function| **odd_function == *path_segment_str);
-                arg = args.first().expect("A method always has a receiver.");
+                arg = receiver;
             }
 
             if_chain! {

clippy_lints/src/suspicious_operation_groupings.rs

@@ -595,7 +595,7 @@ fn ident_difference_expr_with_base_location(
         | (Unary(_, _), Unary(_, _))
         | (Binary(_, _, _), Binary(_, _, _))
         | (Tup(_), Tup(_))
-        | (MethodCall(_, _, _), MethodCall(_, _, _))
+        | (MethodCall(_, _, _, _), MethodCall(_, _, _, _))
         | (Call(_, _), Call(_, _))
         | (ConstBlock(_), ConstBlock(_))
         | (Array(_), Array(_))

clippy_lints/src/unused_rounding.rs

@@ -30,11 +30,10 @@ declare_clippy_lint! {
 declare_lint_pass!(UnusedRounding => [UNUSED_ROUNDING]);
 
 fn is_useless_rounding(expr: &Expr) -> Option<(&str, String)> {
-    if let ExprKind::MethodCall(name_ident, args, _) = &expr.kind
+    if let ExprKind::MethodCall(name_ident, receiver, _, _) = &expr.kind
         && let method_name = name_ident.ident.name.as_str()
         && (method_name == "ceil" || method_name == "round" || method_name == "floor")
-        && !args.is_empty()
-        && let ExprKind::Lit(spanned) = &args[0].kind
+        && let ExprKind::Lit(spanned) = &receiver.kind
         && let LitKind::Float(symbol, ty) = spanned.kind {
             let f = symbol.as_str().parse::<f64>().unwrap();
             let f_str = symbol.to_string() + if let LitFloatType::Suffixed(ty) = ty {

clippy_utils/src/ast_utils.rs

@@ -147,7 +147,9 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         (Array(l), Array(r)) | (Tup(l), Tup(r)) => over(l, r, |l, r| eq_expr(l, r)),
         (Repeat(le, ls), Repeat(re, rs)) => eq_expr(le, re) && eq_expr(&ls.value, &rs.value),
         (Call(lc, la), Call(rc, ra)) => eq_expr(lc, rc) && over(la, ra, |l, r| eq_expr(l, r)),
-        (MethodCall(lc, la, _), MethodCall(rc, ra, _)) => eq_path_seg(lc, rc) && over(la, ra, |l, r| eq_expr(l, r)),
+        (MethodCall(lc, ls, la, _), MethodCall(rc, rs, ra, _)) => {
+            eq_path_seg(lc, rc) && eq_expr(ls, rs) && over(la, ra, |l, r| eq_expr(l, r))
+        },
         (Binary(lo, ll, lr), Binary(ro, rl, rr)) => lo.node == ro.node && eq_expr(ll, rl) && eq_expr(lr, rr),
         (Unary(lo, l), Unary(ro, r)) => mem::discriminant(lo) == mem::discriminant(ro) && eq_expr(l, r),
         (Lit(l), Lit(r)) => l.kind == r.kind,