Rework ast::BinOpKind::to_string and ast::UnOp::to_string.

- Rename them both `as_str`, which is the typical name for a function that returns a `&str`. (`to_string` is appropriate for functions returning `String` or maybe `Cow<'a, str>`.) - Change `UnOp::as_str` from an associated function (weird!) to a method. - Avoid needless `self` dereferences.

Author: nnethercote

clippy_lints/src/formatting.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_note};
 use clippy_utils::is_span_if;
 use clippy_utils::source::snippet_opt;
-use rustc_ast::ast::{BinOpKind, Block, Expr, ExprKind, StmtKind, UnOp};
+use rustc_ast::ast::{BinOpKind, Block, Expr, ExprKind, StmtKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -144,7 +144,7 @@ fn check_assign(cx: &EarlyContext<'_>, expr: &Expr) {
  let eq_span = lhs.span.between(rhs.span);
  if let ExprKind::Unary(op, ref sub_rhs) = rhs.kind {
  if let Some(eq_snippet) = snippet_opt(cx, eq_span) {
- let op = UnOp::to_string(op);
+ let op = op.as_str();
  let eqop_span = lhs.span.between(sub_rhs.span);
  if eq_snippet.ends_with('=') {
  span_lint_and_note(
@@ -177,11 +177,11 @@ fn check_unop(cx: &EarlyContext<'_>, expr: &Expr) {
  && let unop_operand_span = rhs.span.until(un_rhs.span)
  && let Some(binop_snippet) = snippet_opt(cx, binop_span)
  && let Some(unop_operand_snippet) = snippet_opt(cx, unop_operand_span)
- && let binop_str = BinOpKind::to_string(&binop.node)
+ && let binop_str = binop.node.as_str()
  // no space after BinOp operator and space after UnOp operator
  && binop_snippet.ends_with(binop_str) && unop_operand_snippet.ends_with(' ')
  {
- let unop_str = UnOp::to_string(op);
+ let unop_str = op.as_str();
  let eqop_span = lhs.span.between(un_rhs.span);
  span_lint_and_help(
  cx,

clippy_lints/src/precedence.rs

@@ -78,7 +78,7 @@ impl EarlyLintPass for Precedence {
  let sugg = format!(
  "({}) {} ({})",
  snippet_with_applicability(cx, left.span, "..", &mut applicability),
- op.to_string(),
+ op.as_str(),
  snippet_with_applicability(cx, right.span, "..", &mut applicability)
  );
  span_sugg(expr, sugg, applicability);
@@ -87,7 +87,7 @@ impl EarlyLintPass for Precedence {
  let sugg = format!(
  "({}) {} {}",
  snippet_with_applicability(cx, left.span, "..", &mut applicability),
- op.to_string(),
+ op.as_str(),
  snippet_with_applicability(cx, right.span, "..", &mut applicability)
  );
  span_sugg(expr, sugg, applicability);
@@ -96,7 +96,7 @@ impl EarlyLintPass for Precedence {
  let sugg = format!(
  "{} {} ({})",
  snippet_with_applicability(cx, left.span, "..", &mut applicability),
- op.to_string(),
+ op.as_str(),
  snippet_with_applicability(cx, right.span, "..", &mut applicability)
  );
  span_sugg(expr, sugg, applicability);

clippy_lints/src/suspicious_operation_groupings.rs

@@ -298,7 +298,7 @@ fn replace_left_sugg(
 ) -> String {
  format!(
  "{left_suggestion} {} {}",
- binop.op.to_string(),
+ binop.op.as_str(),
  snippet_with_applicability(cx, binop.right.span, "..", applicability),
  )
 }
@@ -312,7 +312,7 @@ fn replace_right_sugg(
  format!(
  "{} {} {right_suggestion}",
  snippet_with_applicability(cx, binop.left.span, "..", applicability),
- binop.op.to_string(),
+ binop.op.as_str(),
  )
 }
 

clippy_utils/src/sugg.rs

@@ -382,7 +382,7 @@ fn binop_to_string(op: AssocOp, lhs: &str, rhs: &str) -> String {
  | AssocOp::GreaterEqual => {
  format!(
  "{lhs} {} {rhs}",
- op.to_ast_binop().expect("Those are AST ops").to_string()
+ op.to_ast_binop().expect("Those are AST ops").as_str()
  )
  },
  AssocOp::Assign => format!("{lhs} = {rhs}"),