parse_format optimize import use

compiler/rustc_parse_format/src/lib.rs

@@ -16,11 +16,8 @@
 #![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
-use std::{iter, str, string};
-
 pub use Alignment::*;
 pub use Count::*;
-pub use Piece::*;
 pub use Position::*;
 use rustc_lexer::unescape;
 
@@ -86,7 +83,7 @@ impl InnerOffset {
 #[derive(Clone, Debug, PartialEq)]
 pub enum Piece<'a> {
     /// A literal string which should directly be emitted
-    String(&'a str),
+    Lit(&'a str),
     /// This describes that formatting should process the next argument (as
     /// specified inside) for emission.
     NextArgument(Box<Argument<'a>>),
@@ -205,11 +202,11 @@ pub enum Count<'a> {
 }
 
 pub struct ParseError {
-    pub description: string::String,
-    pub note: Option<string::String>,
-    pub label: string::String,
+    pub description: String,
+    pub note: Option<String>,
+    pub label: String,
     pub span: InnerSpan,
-    pub secondary_label: Option<(string::String, InnerSpan)>,
+    pub secondary_label: Option<(String, InnerSpan)>,
     pub suggestion: Suggestion,
 }
 
@@ -225,7 +222,7 @@ pub enum Suggestion {
     /// `format!("{foo:?#}")` -> `format!("{foo:#?}")`
     /// `format!("{foo:?x}")` -> `format!("{foo:x?}")`
     /// `format!("{foo:?X}")` -> `format!("{foo:X?}")`
-    ReorderFormatParameter(InnerSpan, string::String),
+    ReorderFormatParameter(InnerSpan, String),
 }
 
 /// The parser structure for interpreting the input format string. This is
@@ -237,7 +234,7 @@ pub enum Suggestion {
 pub struct Parser<'a> {
     mode: ParseMode,
     input: &'a str,
-    cur: iter::Peekable<str::CharIndices<'a>>,
+    cur: std::iter::Peekable<std::str::CharIndices<'a>>,
     /// Error messages accumulated during parsing
     pub errors: Vec<ParseError>,
     /// Current position of implicit positional argument pointer
@@ -278,7 +275,7 @@ impl<'a> Iterator for Parser<'a> {
                     if self.consume('{') {
                         self.last_opening_brace = curr_last_brace;
 
-                        Some(String(self.string(pos + 1)))
+                        Some(Piece::Lit(self.string(pos + 1)))
                     } else {
                         let arg = self.argument(lbrace_end);
                         if let Some(rbrace_pos) = self.consume_closing_brace(&arg) {
@@ -299,13 +296,13 @@ impl<'a> Iterator for Parser<'a> {
                                 _ => self.suggest_positional_arg_instead_of_captured_arg(arg),
                             }
                         }
-                        Some(NextArgument(Box::new(arg)))
+                        Some(Piece::NextArgument(Box::new(arg)))
                     }
                 }
                 '}' => {
                     self.cur.next();
                     if self.consume('}') {
-                        Some(String(self.string(pos + 1)))
+                        Some(Piece::Lit(self.string(pos + 1)))
                     } else {
                         let err_pos = self.to_span_index(pos);
                         self.err_with_note(
@@ -317,7 +314,7 @@ impl<'a> Iterator for Parser<'a> {
                         None
                     }
                 }
-                _ => Some(String(self.string(pos))),
+                _ => Some(Piece::Lit(self.string(pos))),
             }
         } else {
             if self.is_source_literal {
@@ -336,7 +333,7 @@ impl<'a> Parser<'a> {
     pub fn new(
         s: &'a str,
         style: Option<usize>,
-        snippet: Option<string::String>,
+        snippet: Option<String>,
         append_newline: bool,
         mode: ParseMode,
     ) -> Parser<'a> {
@@ -366,7 +363,7 @@ impl<'a> Parser<'a> {
     /// Notifies of an error. The message doesn't actually need to be of type
     /// String, but I think it does when this eventually uses conditions so it
     /// might as well start using it now.
-    fn err<S1: Into<string::String>, S2: Into<string::String>>(
+    fn err<S1: Into<String>, S2: Into<String>>(
         &mut self,
         description: S1,
         label: S2,
@@ -385,11 +382,7 @@ impl<'a> Parser<'a> {
     /// Notifies of an error. The message doesn't actually need to be of type
     /// String, but I think it does when this eventually uses conditions so it
     /// might as well start using it now.
-    fn err_with_note<
-        S1: Into<string::String>,
-        S2: Into<string::String>,
-        S3: Into<string::String>,
-    >(
+    fn err_with_note<S1: Into<String>, S2: Into<String>, S3: Into<String>>(
         &mut self,
         description: S1,
         label: S2,
@@ -974,7 +967,7 @@ impl<'a> Parser<'a> {
 /// in order to properly synthesise the intra-string `Span`s for error diagnostics.
 fn find_width_map_from_snippet(
     input: &str,
-    snippet: Option<string::String>,
+    snippet: Option<String>,
     str_style: Option<usize>,
 ) -> InputStringKind {
     let snippet = match snippet {
@@ -1089,8 +1082,8 @@ fn find_width_map_from_snippet(
     InputStringKind::Literal { width_mappings }
 }
 
-fn unescape_string(string: &str) -> Option<string::String> {
-    let mut buf = string::String::new();
+fn unescape_string(string: &str) -> Option<String> {
+    let mut buf = String::new();
     let mut ok = true;
     unescape::unescape_unicode(string, unescape::Mode::Str, &mut |_, unescaped_char| {
         match unescaped_char {