manual_str_repeat code cleanup. Use Sugg

Author: Jarcho

clippy_lints/src/methods/manual_str_repeat.rs

@@ -1,22 +1,22 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::source::snippet_with_context;
+use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
+use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item, match_type};
 use clippy_utils::{is_expr_path_def_path, paths};
 use if_chain::if_chain;
-use rustc_ast::util::parser::PREC_POSTFIX;
 use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, LangItem};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty, TyS};
 use rustc_span::symbol::{sym, Symbol};
+use std::borrow::Cow;
 
 use super::MANUAL_STR_REPEAT;
 
 enum RepeatKind {
-    Str,
     String,
-    Char,
+    Char(char),
 }
 
 fn get_ty_param(ty: Ty<'_>) -> Option<Ty<'_>> {
@@ -30,8 +30,8 @@ fn get_ty_param(ty: Ty<'_>) -> Option<Ty<'_>> {
 fn parse_repeat_arg(cx: &LateContext<'_>, e: &Expr<'_>) -> Option<RepeatKind> {
     if let ExprKind::Lit(lit) = &e.kind {
         match lit.node {
-            LitKind::Str(..) => Some(RepeatKind::Str),
-            LitKind::Char(_) => Some(RepeatKind::Char),
+            LitKind::Str(..) => Some(RepeatKind::String),
+            LitKind::Char(c) => Some(RepeatKind::Char(c)),
             _ => None,
         }
     } else {
@@ -43,7 +43,7 @@ fn parse_repeat_arg(cx: &LateContext<'_>, e: &Expr<'_>) -> Option<RepeatKind> {
             Some(RepeatKind::String)
         } else {
             let ty = ty.peel_refs();
-            (ty.is_str() || is_type_diagnostic_item(cx, ty, sym::string_type)).then(|| RepeatKind::Str)
+            (ty.is_str() || is_type_diagnostic_item(cx, ty, sym::string_type)).then(|| RepeatKind::String)
         }
     }
 }
@@ -68,17 +68,19 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: Symbol,
         if ctxt == repeat_expr.span.ctxt();
         then {
             let mut app = Applicability::MachineApplicable;
-            let (val_snip, val_is_mac) = snippet_with_context(cx, repeat_arg.span, ctxt, "..", &mut app);
             let count_snip = snippet_with_context(cx, take_arg.span, ctxt, "..", &mut app).0;
 
             let val_str = match repeat_kind {
-                RepeatKind::Str if !val_is_mac && repeat_arg.precedence().order() < PREC_POSTFIX => {
-                    format!("({})", val_snip)
-                },
-                RepeatKind::Str | RepeatKind::String => val_snip.into(),
-                RepeatKind::Char if val_snip == r#"'"'"# => r#""\"""#.into(),
-                RepeatKind::Char if val_snip == r#"'\''"# => r#""'""#.into(),
-                RepeatKind::Char => format!("\"{}\"", &val_snip[1..val_snip.len() - 1]),
+                RepeatKind::Char(_) if repeat_arg.span.ctxt() != ctxt => return,
+                RepeatKind::Char('\'') => r#""'""#.into(),
+                RepeatKind::Char('"') => r#""\"""#.into(),
+                RepeatKind::Char(_) =>
+                    match snippet_with_applicability(cx, repeat_arg.span, "..", &mut app) {
+                        Cow::Owned(s) => Cow::Owned(format!("\"{}\"", &s[1..s.len() - 1])),
+                        s @ Cow::Borrowed(_) => s,
+                    },
+                RepeatKind::String =>
+                    Sugg::hir_with_context(cx, repeat_arg, ctxt, "..", &mut app).maybe_par().to_string().into(),
             };
 
             span_lint_and_sugg(

clippy_utils/src/sugg.rs

@@ -2,15 +2,15 @@
 #![deny(clippy::missing_docs_in_private_items)]
 
 use crate::higher;
-use crate::source::{snippet, snippet_opt, snippet_with_macro_callsite};
+use crate::source::{snippet, snippet_opt, snippet_with_context, snippet_with_macro_callsite};
 use rustc_ast::util::parser::AssocOp;
 use rustc_ast::{ast, token};
 use rustc_ast_pretty::pprust::token_kind_to_string;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::{EarlyContext, LateContext, LintContext};
 use rustc_span::source_map::{CharPos, Span};
-use rustc_span::{BytePos, Pos};
+use rustc_span::{BytePos, Pos, SyntaxContext};
 use std::borrow::Cow;
 use std::convert::TryInto;
 use std::fmt::Display;
@@ -90,6 +90,29 @@ impl<'a> Sugg<'a> {
         Self::hir_from_snippet(expr, snippet)
     }
 
+    /// Same as `hir`, but first walks the span up to the given context. This will result in the
+    /// macro call, rather then the expansion, if the span is from a child context. If the span is
+    /// not from a child context, it will be used directly instead.
+    ///
+    /// e.g. Given the expression `&vec![]`, getting a snippet from the span for `vec![]` as a HIR
+    /// node would result in `box []`. If given the context of the address of expression, this
+    /// function will correctly get a snippet of `vec![]`.
+    pub fn hir_with_context(
+        cx: &LateContext<'_>,
+        expr: &hir::Expr<'_>,
+        ctxt: SyntaxContext,
+        default: &'a str,
+        applicability: &mut Applicability,
+    ) -> Self {
+        let (snippet, in_macro) = snippet_with_context(cx, expr.span, ctxt, default, applicability);
+
+        if in_macro {
+            Sugg::NonParen(snippet)
+        } else {
+            Self::hir_from_snippet(expr, snippet)
+        }
+    }
+
     /// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*`
     /// function variants of `Sugg`, since these use different snippet functions.
     fn hir_from_snippet(expr: &hir::Expr<'_>, snippet: Cow<'a, str>) -> Self {