From 7c11a53f9ccb4040995b9e054b093a47fef29cc1 Mon Sep 17 00:00:00 2001
From: yukang <moorekang@gmail.com>
Date: Fri, 25 Nov 2022 17:11:47 +0800
Subject: fix #104867, Properly handle postfix inc/dec in standalone and
 subexpr scenarios

---
 compiler/rustc_parse/src/parser/diagnostics.rs | 57 ++++++++------------------
 compiler/rustc_parse/src/parser/expr.rs        | 10 ++++-
 2 files changed, 25 insertions(+), 42 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 3f5baf343c9..eba0f22f37f 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -159,8 +159,6 @@ enum IsStandalone {
     Standalone,
     /// It's a subexpression, i.e., *not* standalone.
     Subexpr,
-    /// It's maybe standalone; we're not sure.
-    Maybe,
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
@@ -213,14 +211,8 @@ impl MultiSugg {
         err.multipart_suggestion(&self.msg, self.patches, self.applicability);
     }
 
-    /// Overrides individual messages and applicabilities.
-    fn emit_many(
-        err: &mut Diagnostic,
-        msg: &str,
-        applicability: Applicability,
-        suggestions: impl Iterator<Item = Self>,
-    ) {
-        err.multipart_suggestions(msg, suggestions.map(|s| s.patches), applicability);
+    fn emit_verbose(self, err: &mut Diagnostic) {
+        err.multipart_suggestion_verbose(&self.msg, self.patches, self.applicability);
     }
 }
 
@@ -1272,7 +1264,6 @@ impl<'a> Parser<'a> {
         let standalone =
             if prev_is_semi { IsStandalone::Standalone } else { IsStandalone::Subexpr };
         let kind = IncDecRecovery { standalone, op: IncOrDec::Inc, fixity: UnaryFixity::Pre };
-
         self.recover_from_inc_dec(operand_expr, kind, op_span)
     }
 
@@ -1280,13 +1271,13 @@ impl<'a> Parser<'a> {
         &mut self,
         operand_expr: P<Expr>,
         op_span: Span,
+        prev_is_semi: bool,
     ) -> PResult<'a, P<Expr>> {
         let kind = IncDecRecovery {
-            standalone: IsStandalone::Maybe,
+            standalone: if prev_is_semi { IsStandalone::Standalone } else { IsStandalone::Subexpr },
             op: IncOrDec::Inc,
             fixity: UnaryFixity::Post,
         };
-
         self.recover_from_inc_dec(operand_expr, kind, op_span)
     }
 
@@ -1314,35 +1305,20 @@ impl<'a> Parser<'a> {
             UnaryFixity::Post => (base.span.shrink_to_lo(), op_span),
         };
 
+        let Ok(base_src) = self.span_to_snippet(base.span)
+        else { return help_base_case(err, base) };
         match kind.standalone {
-            IsStandalone::Standalone => self.inc_dec_standalone_suggest(kind, spans).emit(&mut err),
-            IsStandalone::Subexpr => {
-                let Ok(base_src) = self.span_to_snippet(base.span)
-                    else { return help_base_case(err, base) };
-                match kind.fixity {
-                    UnaryFixity::Pre => {
-                        self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
-                    }
-                    UnaryFixity::Post => {
-                        self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
-                    }
-                }
-            }
-            IsStandalone::Maybe => {
-                let Ok(base_src) = self.span_to_snippet(base.span)
-                    else { return help_base_case(err, base) };
-                let sugg1 = match kind.fixity {
-                    UnaryFixity::Pre => self.prefix_inc_dec_suggest(base_src, kind, spans),
-                    UnaryFixity::Post => self.postfix_inc_dec_suggest(base_src, kind, spans),
-                };
-                let sugg2 = self.inc_dec_standalone_suggest(kind, spans);
-                MultiSugg::emit_many(
-                    &mut err,
-                    "use `+= 1` instead",
-                    Applicability::Unspecified,
-                    [sugg1, sugg2].into_iter(),
-                )
+            IsStandalone::Standalone => {
+                self.inc_dec_standalone_suggest(kind, spans).emit_verbose(&mut err)
             }
+            IsStandalone::Subexpr => match kind.fixity {
+                UnaryFixity::Pre => {
+                    self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                }
+                UnaryFixity::Post => {
+                    self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                }
+            },
         }
         Err(err)
     }
@@ -1392,7 +1368,6 @@ impl<'a> Parser<'a> {
         }
 
         patches.push((post_span, format!(" {}= 1", kind.op.chr())));
-
         MultiSugg {
             msg: format!("use `{}= 1` instead", kind.op.chr()),
             patches,
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 9f2267efb82..b98372d0f28 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -292,7 +292,15 @@ impl<'a> Parser<'a> {
                 let op_span = self.prev_token.span.to(self.token.span);
                 // Eat the second `+`
                 self.bump();
-                lhs = self.recover_from_postfix_increment(lhs, op_span)?;
+                let prev_is_semi = {
+                    if let Ok(prev_code) = self.sess.source_map().span_to_prev_source(lhs.span) &&
+                          prev_code.trim_end().ends_with(";") {
+                            true
+                    } else {
+                        false
+                    }
+                };
+                lhs = self.recover_from_postfix_increment(lhs, op_span, prev_is_semi)?;
                 continue;
             }
 
-- 
cgit 1.4.1-3-g733a5


From dee85a391f091f314a24fb5a090f2e528f4eb81c Mon Sep 17 00:00:00 2001
From: yukang <moorekang@gmail.com>
Date: Sat, 26 Nov 2022 05:33:13 +0800
Subject: add start_stmt to handle postfix increment

---
 compiler/rustc_parse/src/parser/diagnostics.rs   | 29 ++++----
 compiler/rustc_parse/src/parser/expr.rs          | 23 +++---
 compiler/rustc_parse/src/parser/stmt.rs          |  4 +-
 src/test/ui/parser/increment-autofix-2.fixed     | 63 +++++++++++++++++
 src/test/ui/parser/increment-autofix-2.rs        | 63 +++++++++++++++++
 src/test/ui/parser/increment-autofix-2.stderr    | 84 ++++++++++++++++++++++
 src/test/ui/parser/increment-notfixed.fixed      | 63 -----------------
 src/test/ui/parser/increment-notfixed.rs         | 63 -----------------
 src/test/ui/parser/increment-notfixed.stderr     | 84 ----------------------
 src/test/ui/parser/issue-104867-inc-dec-2.rs     | 41 +++++++++++
 src/test/ui/parser/issue-104867-inc-dec-2.stderr | 90 ++++++++++++++++++++++++
 src/test/ui/parser/issue-104867-inc-dec.rs       | 15 ++++
 src/test/ui/parser/issue-104867-inc-dec.stderr   | 25 ++++++-
 13 files changed, 406 insertions(+), 241 deletions(-)
 create mode 100644 src/test/ui/parser/increment-autofix-2.fixed
 create mode 100644 src/test/ui/parser/increment-autofix-2.rs
 create mode 100644 src/test/ui/parser/increment-autofix-2.stderr
 delete mode 100644 src/test/ui/parser/increment-notfixed.fixed
 delete mode 100644 src/test/ui/parser/increment-notfixed.rs
 delete mode 100644 src/test/ui/parser/increment-notfixed.stderr
 create mode 100644 src/test/ui/parser/issue-104867-inc-dec-2.rs
 create mode 100644 src/test/ui/parser/issue-104867-inc-dec-2.stderr

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index eba0f22f37f..f8c6ff994c4 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1259,10 +1259,9 @@ impl<'a> Parser<'a> {
         &mut self,
         operand_expr: P<Expr>,
         op_span: Span,
-        prev_is_semi: bool,
+        start_stmt: bool,
     ) -> PResult<'a, P<Expr>> {
-        let standalone =
-            if prev_is_semi { IsStandalone::Standalone } else { IsStandalone::Subexpr };
+        let standalone = if start_stmt { IsStandalone::Standalone } else { IsStandalone::Subexpr };
         let kind = IncDecRecovery { standalone, op: IncOrDec::Inc, fixity: UnaryFixity::Pre };
         self.recover_from_inc_dec(operand_expr, kind, op_span)
     }
@@ -1271,10 +1270,10 @@ impl<'a> Parser<'a> {
         &mut self,
         operand_expr: P<Expr>,
         op_span: Span,
-        prev_is_semi: bool,
+        start_stmt: bool,
     ) -> PResult<'a, P<Expr>> {
         let kind = IncDecRecovery {
-            standalone: if prev_is_semi { IsStandalone::Standalone } else { IsStandalone::Subexpr },
+            standalone: if start_stmt { IsStandalone::Standalone } else { IsStandalone::Subexpr },
             op: IncOrDec::Inc,
             fixity: UnaryFixity::Post,
         };
@@ -1305,20 +1304,22 @@ impl<'a> Parser<'a> {
             UnaryFixity::Post => (base.span.shrink_to_lo(), op_span),
         };
 
-        let Ok(base_src) = self.span_to_snippet(base.span)
-        else { return help_base_case(err, base) };
         match kind.standalone {
             IsStandalone::Standalone => {
                 self.inc_dec_standalone_suggest(kind, spans).emit_verbose(&mut err)
             }
-            IsStandalone::Subexpr => match kind.fixity {
-                UnaryFixity::Pre => {
-                    self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
-                }
-                UnaryFixity::Post => {
-                    self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+            IsStandalone::Subexpr => {
+                let Ok(base_src) = self.span_to_snippet(base.span)
+                else { return help_base_case(err, base) };
+                match kind.fixity {
+                    UnaryFixity::Pre => {
+                        self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                    }
+                    UnaryFixity::Post => {
+                        self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                    }
                 }
-            },
+            }
         }
         Err(err)
     }
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index b98372d0f28..36fe328cb19 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -83,7 +83,7 @@ macro_rules! maybe_whole_expr {
 pub(super) enum LhsExpr {
     NotYetParsed,
     AttributesParsed(AttrWrapper),
-    AlreadyParsed(P<Expr>),
+    AlreadyParsed(P<Expr>, bool), // (expr, starts_statement)
 }
 
 impl From<Option<AttrWrapper>> for LhsExpr {
@@ -101,7 +101,7 @@ impl From<P<Expr>> for LhsExpr {
     ///
     /// This conversion does not allocate.
     fn from(expr: P<Expr>) -> Self {
-        LhsExpr::AlreadyParsed(expr)
+        LhsExpr::AlreadyParsed(expr, false)
     }
 }
 
@@ -173,7 +173,9 @@ impl<'a> Parser<'a> {
         min_prec: usize,
         lhs: LhsExpr,
     ) -> PResult<'a, P<Expr>> {
-        let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs {
+        let mut starts_stmt = false;
+        let mut lhs = if let LhsExpr::AlreadyParsed(expr, starts_statement) = lhs {
+            starts_stmt = starts_statement;
             expr
         } else {
             let attrs = match lhs {
@@ -292,15 +294,7 @@ impl<'a> Parser<'a> {
                 let op_span = self.prev_token.span.to(self.token.span);
                 // Eat the second `+`
                 self.bump();
-                let prev_is_semi = {
-                    if let Ok(prev_code) = self.sess.source_map().span_to_prev_source(lhs.span) &&
-                          prev_code.trim_end().ends_with(";") {
-                            true
-                    } else {
-                        false
-                    }
-                };
-                lhs = self.recover_from_postfix_increment(lhs, op_span, prev_is_semi)?;
+                lhs = self.recover_from_postfix_increment(lhs, op_span, starts_stmt)?;
                 continue;
             }
 
@@ -607,14 +601,15 @@ impl<'a> Parser<'a> {
             token::BinOp(token::Plus)
                 if this.look_ahead(1, |t| *t == token::BinOp(token::Plus)) =>
             {
-                let prev_is_semi = this.prev_token == token::Semi;
+                let starts_stmt = this.prev_token == token::Semi
+                    || this.prev_token == token::CloseDelim(Delimiter::Brace);
                 let pre_span = this.token.span.to(this.look_ahead(1, |t| t.span));
                 // Eat both `+`s.
                 this.bump();
                 this.bump();
 
                 let operand_expr = this.parse_dot_or_call_expr(Default::default())?;
-                this.recover_from_prefix_increment(operand_expr, pre_span, prev_is_semi)
+                this.recover_from_prefix_increment(operand_expr, pre_span, starts_stmt)
             }
             token::Ident(..) if this.token.is_keyword(kw::Box) => {
                 make_it!(this, attrs, |this, _| this.parse_box_expr(lo))
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index 1b56cd72db0..53aa0315151 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -156,7 +156,7 @@ impl<'a> Parser<'a> {
             // Perform this outside of the `collect_tokens_trailing_token` closure,
             // since our outer attributes do not apply to this part of the expression
             let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
-                this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
+                this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr, true))
             })?;
             Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr)))
         } else {
@@ -190,7 +190,7 @@ impl<'a> Parser<'a> {
             let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac));
             let e = self.maybe_recover_from_bad_qpath(e)?;
             let e = self.parse_dot_or_call_expr_with(e, lo, attrs)?;
-            let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
+            let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e, false))?;
             StmtKind::Expr(e)
         };
         Ok(self.mk_stmt(lo.to(hi), kind))
diff --git a/src/test/ui/parser/increment-autofix-2.fixed b/src/test/ui/parser/increment-autofix-2.fixed
new file mode 100644
index 00000000000..580ebaf5dbb
--- /dev/null
+++ b/src/test/ui/parser/increment-autofix-2.fixed
@@ -0,0 +1,63 @@
+// run-rustfix
+
+struct Foo {
+    bar: Bar,
+}
+
+struct Bar {
+    qux: i32,
+}
+
+pub fn post_regular() {
+    let mut i = 0;
+    i += 1; //~ ERROR Rust has no postfix increment operator
+    println!("{}", i);
+}
+
+pub fn post_while() {
+    let mut i = 0;
+    while { let tmp = i; i += 1; tmp } < 5 {
+        //~^ ERROR Rust has no postfix increment operator
+        println!("{}", i);
+    }
+}
+
+pub fn post_regular_tmp() {
+    let mut tmp = 0;
+    tmp += 1; //~ ERROR Rust has no postfix increment operator
+    println!("{}", tmp);
+}
+
+pub fn post_while_tmp() {
+    let mut tmp = 0;
+    while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
+        //~^ ERROR Rust has no postfix increment operator
+        println!("{}", tmp);
+    }
+}
+
+pub fn post_field() {
+    let mut foo = Foo { bar: Bar { qux: 0 } };
+    foo.bar.qux += 1;
+    //~^ ERROR Rust has no postfix increment operator
+    println!("{}", foo.bar.qux);
+}
+
+pub fn post_field_tmp() {
+    struct S {
+        tmp: i32
+    }
+    let mut s = S { tmp: 0 };
+    s.tmp += 1;
+    //~^ ERROR Rust has no postfix increment operator
+    println!("{}", s.tmp);
+}
+
+pub fn pre_field() {
+    let mut foo = Foo { bar: Bar { qux: 0 } };
+    foo.bar.qux += 1;
+    //~^ ERROR Rust has no prefix increment operator
+    println!("{}", foo.bar.qux);
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/increment-autofix-2.rs b/src/test/ui/parser/increment-autofix-2.rs
new file mode 100644
index 00000000000..ebe5fa6ca1e
--- /dev/null
+++ b/src/test/ui/parser/increment-autofix-2.rs
@@ -0,0 +1,63 @@
+// run-rustfix
+
+struct Foo {
+    bar: Bar,
+}
+
+struct Bar {
+    qux: i32,
+}
+
+pub fn post_regular() {
+    let mut i = 0;
+    i++; //~ ERROR Rust has no postfix increment operator
+    println!("{}", i);
+}
+
+pub fn post_while() {
+    let mut i = 0;
+    while i++ < 5 {
+        //~^ ERROR Rust has no postfix increment operator
+        println!("{}", i);
+    }
+}
+
+pub fn post_regular_tmp() {
+    let mut tmp = 0;
+    tmp++; //~ ERROR Rust has no postfix increment operator
+    println!("{}", tmp);
+}
+
+pub fn post_while_tmp() {
+    let mut tmp = 0;
+    while tmp++ < 5 {
+        //~^ ERROR Rust has no postfix increment operator
+        println!("{}", tmp);
+    }
+}
+
+pub fn post_field() {
+    let mut foo = Foo { bar: Bar { qux: 0 } };
+    foo.bar.qux++;
+    //~^ ERROR Rust has no postfix increment operator
+    println!("{}", foo.bar.qux);
+}
+
+pub fn post_field_tmp() {
+    struct S {
+        tmp: i32
+    }
+    let mut s = S { tmp: 0 };
+    s.tmp++;
+    //~^ ERROR Rust has no postfix increment operator
+    println!("{}", s.tmp);
+}
+
+pub fn pre_field() {
+    let mut foo = Foo { bar: Bar { qux: 0 } };
+    ++foo.bar.qux;
+    //~^ ERROR Rust has no prefix increment operator
+    println!("{}", foo.bar.qux);
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/increment-autofix-2.stderr b/src/test/ui/parser/increment-autofix-2.stderr
new file mode 100644
index 00000000000..11e985480d6
--- /dev/null
+++ b/src/test/ui/parser/increment-autofix-2.stderr
@@ -0,0 +1,84 @@
+error: Rust has no postfix increment operator
+  --> $DIR/increment-autofix-2.rs:13:6
+   |
+LL |     i++;
+   |      ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     i += 1;
+   |       ~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/increment-autofix-2.rs:19:12
+   |
+LL |     while i++ < 5 {
+   |     -----  ^^ not a valid postfix operator
+   |     |
+   |     while parsing the condition of this `while` expression
+   |
+help: use `+= 1` instead
+   |
+LL |     while { let tmp = i; i += 1; tmp } < 5 {
+   |           +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/increment-autofix-2.rs:27:8
+   |
+LL |     tmp++;
+   |        ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     tmp += 1;
+   |         ~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/increment-autofix-2.rs:33:14
+   |
+LL |     while tmp++ < 5 {
+   |     -----    ^^ not a valid postfix operator
+   |     |
+   |     while parsing the condition of this `while` expression
+   |
+help: use `+= 1` instead
+   |
+LL |     while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
+   |           ++++++++++++    ~~~~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/increment-autofix-2.rs:41:16
+   |
+LL |     foo.bar.qux++;
+   |                ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     foo.bar.qux += 1;
+   |                 ~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/increment-autofix-2.rs:51:10
+   |
+LL |     s.tmp++;
+   |          ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     s.tmp += 1;
+   |           ~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/increment-autofix-2.rs:58:5
+   |
+LL |     ++foo.bar.qux;
+   |     ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL -     ++foo.bar.qux;
+LL +     foo.bar.qux += 1;
+   |
+
+error: aborting due to 7 previous errors
+
diff --git a/src/test/ui/parser/increment-notfixed.fixed b/src/test/ui/parser/increment-notfixed.fixed
deleted file mode 100644
index 580ebaf5dbb..00000000000
--- a/src/test/ui/parser/increment-notfixed.fixed
+++ /dev/null
@@ -1,63 +0,0 @@
-// run-rustfix
-
-struct Foo {
-    bar: Bar,
-}
-
-struct Bar {
-    qux: i32,
-}
-
-pub fn post_regular() {
-    let mut i = 0;
-    i += 1; //~ ERROR Rust has no postfix increment operator
-    println!("{}", i);
-}
-
-pub fn post_while() {
-    let mut i = 0;
-    while { let tmp = i; i += 1; tmp } < 5 {
-        //~^ ERROR Rust has no postfix increment operator
-        println!("{}", i);
-    }
-}
-
-pub fn post_regular_tmp() {
-    let mut tmp = 0;
-    tmp += 1; //~ ERROR Rust has no postfix increment operator
-    println!("{}", tmp);
-}
-
-pub fn post_while_tmp() {
-    let mut tmp = 0;
-    while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
-        //~^ ERROR Rust has no postfix increment operator
-        println!("{}", tmp);
-    }
-}
-
-pub fn post_field() {
-    let mut foo = Foo { bar: Bar { qux: 0 } };
-    foo.bar.qux += 1;
-    //~^ ERROR Rust has no postfix increment operator
-    println!("{}", foo.bar.qux);
-}
-
-pub fn post_field_tmp() {
-    struct S {
-        tmp: i32
-    }
-    let mut s = S { tmp: 0 };
-    s.tmp += 1;
-    //~^ ERROR Rust has no postfix increment operator
-    println!("{}", s.tmp);
-}
-
-pub fn pre_field() {
-    let mut foo = Foo { bar: Bar { qux: 0 } };
-    foo.bar.qux += 1;
-    //~^ ERROR Rust has no prefix increment operator
-    println!("{}", foo.bar.qux);
-}
-
-fn main() {}
diff --git a/src/test/ui/parser/increment-notfixed.rs b/src/test/ui/parser/increment-notfixed.rs
deleted file mode 100644
index ebe5fa6ca1e..00000000000
--- a/src/test/ui/parser/increment-notfixed.rs
+++ /dev/null
@@ -1,63 +0,0 @@
-// run-rustfix
-
-struct Foo {
-    bar: Bar,
-}
-
-struct Bar {
-    qux: i32,
-}
-
-pub fn post_regular() {
-    let mut i = 0;
-    i++; //~ ERROR Rust has no postfix increment operator
-    println!("{}", i);
-}
-
-pub fn post_while() {
-    let mut i = 0;
-    while i++ < 5 {
-        //~^ ERROR Rust has no postfix increment operator
-        println!("{}", i);
-    }
-}
-
-pub fn post_regular_tmp() {
-    let mut tmp = 0;
-    tmp++; //~ ERROR Rust has no postfix increment operator
-    println!("{}", tmp);
-}
-
-pub fn post_while_tmp() {
-    let mut tmp = 0;
-    while tmp++ < 5 {
-        //~^ ERROR Rust has no postfix increment operator
-        println!("{}", tmp);
-    }
-}
-
-pub fn post_field() {
-    let mut foo = Foo { bar: Bar { qux: 0 } };
-    foo.bar.qux++;
-    //~^ ERROR Rust has no postfix increment operator
-    println!("{}", foo.bar.qux);
-}
-
-pub fn post_field_tmp() {
-    struct S {
-        tmp: i32
-    }
-    let mut s = S { tmp: 0 };
-    s.tmp++;
-    //~^ ERROR Rust has no postfix increment operator
-    println!("{}", s.tmp);
-}
-
-pub fn pre_field() {
-    let mut foo = Foo { bar: Bar { qux: 0 } };
-    ++foo.bar.qux;
-    //~^ ERROR Rust has no prefix increment operator
-    println!("{}", foo.bar.qux);
-}
-
-fn main() {}
diff --git a/src/test/ui/parser/increment-notfixed.stderr b/src/test/ui/parser/increment-notfixed.stderr
deleted file mode 100644
index ffee8b64637..00000000000
--- a/src/test/ui/parser/increment-notfixed.stderr
+++ /dev/null
@@ -1,84 +0,0 @@
-error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:13:6
-   |
-LL |     i++;
-   |      ^^ not a valid postfix operator
-   |
-help: use `+= 1` instead
-   |
-LL |     i += 1;
-   |       ~~~~
-
-error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:19:12
-   |
-LL |     while i++ < 5 {
-   |     -----  ^^ not a valid postfix operator
-   |     |
-   |     while parsing the condition of this `while` expression
-   |
-help: use `+= 1` instead
-   |
-LL |     while { let tmp = i; i += 1; tmp } < 5 {
-   |           +++++++++++  ~~~~~~~~~~~~~~~
-
-error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:27:8
-   |
-LL |     tmp++;
-   |        ^^ not a valid postfix operator
-   |
-help: use `+= 1` instead
-   |
-LL |     tmp += 1;
-   |         ~~~~
-
-error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:33:14
-   |
-LL |     while tmp++ < 5 {
-   |     -----    ^^ not a valid postfix operator
-   |     |
-   |     while parsing the condition of this `while` expression
-   |
-help: use `+= 1` instead
-   |
-LL |     while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
-   |           ++++++++++++    ~~~~~~~~~~~~~~~~~~
-
-error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:41:16
-   |
-LL |     foo.bar.qux++;
-   |                ^^ not a valid postfix operator
-   |
-help: use `+= 1` instead
-   |
-LL |     foo.bar.qux += 1;
-   |                 ~~~~
-
-error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:51:10
-   |
-LL |     s.tmp++;
-   |          ^^ not a valid postfix operator
-   |
-help: use `+= 1` instead
-   |
-LL |     s.tmp += 1;
-   |           ~~~~
-
-error: Rust has no prefix increment operator
-  --> $DIR/increment-notfixed.rs:58:5
-   |
-LL |     ++foo.bar.qux;
-   |     ^^ not a valid prefix operator
-   |
-help: use `+= 1` instead
-   |
-LL -     ++foo.bar.qux;
-LL +     foo.bar.qux += 1;
-   |
-
-error: aborting due to 7 previous errors
-
diff --git a/src/test/ui/parser/issue-104867-inc-dec-2.rs b/src/test/ui/parser/issue-104867-inc-dec-2.rs
new file mode 100644
index 00000000000..e64dfbcdc28
--- /dev/null
+++ b/src/test/ui/parser/issue-104867-inc-dec-2.rs
@@ -0,0 +1,41 @@
+fn test1() {
+    let mut i = 0;
+    let _ = i + ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test2() {
+    let mut i = 0;
+    let _ = ++i + i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test3() {
+    let mut i = 0;
+    let _ = ++i + ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test4() {
+    let mut i = 0;
+    let _ = i + i++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test5() {
+    let mut i = 0;
+    let _ = i++ + i; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test6() {
+    let mut i = 0;
+    let _ = i++ + i++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test7() {
+    let mut i = 0;
+    let _ = ++i + i++; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test8() {
+    let mut i = 0;
+    let _ = i++ + ++i; //~ ERROR Rust has no postfix increment operator
+}
+
+fn main() { }
diff --git a/src/test/ui/parser/issue-104867-inc-dec-2.stderr b/src/test/ui/parser/issue-104867-inc-dec-2.stderr
new file mode 100644
index 00000000000..21cfa4e8b78
--- /dev/null
+++ b/src/test/ui/parser/issue-104867-inc-dec-2.stderr
@@ -0,0 +1,90 @@
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:3:17
+   |
+LL |     let _ = i + ++i;
+   |                 ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = i + { i += 1; i };
+   |                 ~   +++++++++
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:8:13
+   |
+LL |     let _ = ++i + i;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + i;
+   |             ~   +++++++++
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:13:13
+   |
+LL |     let _ = ++i + ++i;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + ++i;
+   |             ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:18:18
+   |
+LL |     let _ = i + i++;
+   |                  ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i + i; i + i += 1; tmp };
+   |             +++++++++++      ~~~~~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:23:14
+   |
+LL |     let _ = i++ + i;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + i;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:28:14
+   |
+LL |     let _ = i++ + i++;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + i++;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:33:13
+   |
+LL |     let _ = ++i + i++;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + i++;
+   |             ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:38:14
+   |
+LL |     let _ = i++ + ++i;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + ++i;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: aborting due to 8 previous errors
+
diff --git a/src/test/ui/parser/issue-104867-inc-dec.rs b/src/test/ui/parser/issue-104867-inc-dec.rs
index d08d74ec1f9..760c67b4bed 100644
--- a/src/test/ui/parser/issue-104867-inc-dec.rs
+++ b/src/test/ui/parser/issue-104867-inc-dec.rs
@@ -27,4 +27,19 @@ fn test5() {
     if ++i == 1 { } //~ ERROR Rust has no prefix increment operator
 }
 
+fn test6() {
+    let mut i = 0;
+    loop { break; }
+    i++; //~ ERROR Rust has no postfix increment operator
+    loop { break; }
+    ++i;
+}
+
+fn test7() {
+    let mut i = 0;
+    loop { break; }
+    ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+
 fn main() {}
diff --git a/src/test/ui/parser/issue-104867-inc-dec.stderr b/src/test/ui/parser/issue-104867-inc-dec.stderr
index d45b92bf899..78bfd3e82f0 100644
--- a/src/test/ui/parser/issue-104867-inc-dec.stderr
+++ b/src/test/ui/parser/issue-104867-inc-dec.stderr
@@ -54,5 +54,28 @@ help: use `+= 1` instead
 LL |     if { i += 1; i } == 1 { }
    |        ~   +++++++++
 
-error: aborting due to 5 previous errors
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:33:6
+   |
+LL |     i++;
+   |      ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     i += 1;
+   |       ~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:41:5
+   |
+LL |     ++i;
+   |     ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL -     ++i;
+LL +     i += 1;
+   |
+
+error: aborting due to 7 previous errors
 
-- 
cgit 1.4.1-3-g733a5


From ded10a13d2a0ccb4475cb7a330179a1f39e2b4ff Mon Sep 17 00:00:00 2001
From: yukang <moorekang@gmail.com>
Date: Sat, 26 Nov 2022 07:10:04 +0800
Subject: will not suggest for postfix operator when can not handle precedences
 well

---
 compiler/rustc_parse/src/parser/diagnostics.rs   |  6 +++-
 src/test/ui/parser/issue-104867-inc-dec-2.rs     | 11 +++++++
 src/test/ui/parser/issue-104867-inc-dec-2.stderr | 37 +++++++++++++++++-------
 3 files changed, 43 insertions(+), 11 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index f8c6ff994c4..a9555cddb1b 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1316,7 +1316,11 @@ impl<'a> Parser<'a> {
                         self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
                     }
                     UnaryFixity::Post => {
-                        self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                        // won't suggest since we can not handle the precedences
+                        // for example: `a + b++` has been parsed (a + b)++ and we can not suggest here
+                        if !matches!(base.kind, ExprKind::Binary(_, _, _)) {
+                            self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                        }
                     }
                 }
             }
diff --git a/src/test/ui/parser/issue-104867-inc-dec-2.rs b/src/test/ui/parser/issue-104867-inc-dec-2.rs
index e64dfbcdc28..a006421a975 100644
--- a/src/test/ui/parser/issue-104867-inc-dec-2.rs
+++ b/src/test/ui/parser/issue-104867-inc-dec-2.rs
@@ -16,6 +16,7 @@ fn test3() {
 fn test4() {
     let mut i = 0;
     let _ = i + i++; //~ ERROR Rust has no postfix increment operator
+    // won't suggest since we can not handle the precedences
 }
 
 fn test5() {
@@ -38,4 +39,14 @@ fn test8() {
     let _ = i++ + ++i; //~ ERROR Rust has no postfix increment operator
 }
 
+fn test9() {
+    let mut i = 0;
+    let _ = (1 + 2 + i)++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test10() {
+    let mut i = 0;
+    let _ = (i++ + 1) + 2; //~ ERROR Rust has no postfix increment operator
+}
+
 fn main() { }
diff --git a/src/test/ui/parser/issue-104867-inc-dec-2.stderr b/src/test/ui/parser/issue-104867-inc-dec-2.stderr
index 21cfa4e8b78..4e2d0546851 100644
--- a/src/test/ui/parser/issue-104867-inc-dec-2.stderr
+++ b/src/test/ui/parser/issue-104867-inc-dec-2.stderr
@@ -36,14 +36,9 @@ error: Rust has no postfix increment operator
    |
 LL |     let _ = i + i++;
    |                  ^^ not a valid postfix operator
-   |
-help: use `+= 1` instead
-   |
-LL |     let _ = { let tmp = i + i; i + i += 1; tmp };
-   |             +++++++++++      ~~~~~~~~~~~~~~~~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/issue-104867-inc-dec-2.rs:23:14
+  --> $DIR/issue-104867-inc-dec-2.rs:24:14
    |
 LL |     let _ = i++ + i;
    |              ^^ not a valid postfix operator
@@ -54,7 +49,7 @@ LL |     let _ = { let tmp = i; i += 1; tmp } + i;
    |             +++++++++++  ~~~~~~~~~~~~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/issue-104867-inc-dec-2.rs:28:14
+  --> $DIR/issue-104867-inc-dec-2.rs:29:14
    |
 LL |     let _ = i++ + i++;
    |              ^^ not a valid postfix operator
@@ -65,7 +60,7 @@ LL |     let _ = { let tmp = i; i += 1; tmp } + i++;
    |             +++++++++++  ~~~~~~~~~~~~~~~
 
 error: Rust has no prefix increment operator
-  --> $DIR/issue-104867-inc-dec-2.rs:33:13
+  --> $DIR/issue-104867-inc-dec-2.rs:34:13
    |
 LL |     let _ = ++i + i++;
    |             ^^ not a valid prefix operator
@@ -76,7 +71,7 @@ LL |     let _ = { i += 1; i } + i++;
    |             ~   +++++++++
 
 error: Rust has no postfix increment operator
-  --> $DIR/issue-104867-inc-dec-2.rs:38:14
+  --> $DIR/issue-104867-inc-dec-2.rs:39:14
    |
 LL |     let _ = i++ + ++i;
    |              ^^ not a valid postfix operator
@@ -86,5 +81,27 @@ help: use `+= 1` instead
 LL |     let _ = { let tmp = i; i += 1; tmp } + ++i;
    |             +++++++++++  ~~~~~~~~~~~~~~~
 
-error: aborting due to 8 previous errors
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:44:24
+   |
+LL |     let _ = (1 + 2 + i)++;
+   |                        ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = (1 + 2 + i); (1 + 2 + i) += 1; tmp };
+   |             +++++++++++            ~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:49:15
+   |
+LL |     let _ = (i++ + 1) + 2;
+   |               ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = ({ let tmp = i; i += 1; tmp } + 1) + 2;
+   |              +++++++++++  ~~~~~~~~~~~~~~~
+
+error: aborting due to 10 previous errors
 
-- 
cgit 1.4.1-3-g733a5


From 2fd364acff5f962b0ce4f4dffb5ae085d5f2b67a Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Tue, 29 Nov 2022 13:36:00 +1100
Subject: Remove `token::Lit` from `ast::MetaItemLit`.

`token::Lit` contains a `kind` field that indicates what kind of literal
it is. `ast::MetaItemLit` currently wraps a `token::Lit` but also has
its own `kind` field. This means that `ast::MetaItemLit` encodes the
literal kind in two different ways.

This commit changes `ast::MetaItemLit` so it no longer wraps
`token::Lit`. It now contains the `symbol` and `suffix` fields from
`token::Lit`, but not the `kind` field, eliminating the redundancy.
---
 compiler/rustc_ast/src/ast.rs                 |  8 +++++---
 compiler/rustc_ast/src/attr/mod.rs            |  4 +++-
 compiler/rustc_ast/src/util/literal.rs        | 27 +++++++++++++++++++++++++--
 compiler/rustc_ast_lowering/src/lib.rs        |  3 ++-
 compiler/rustc_ast_pretty/src/pprust/state.rs |  2 +-
 compiler/rustc_builtin_macros/src/derive.rs   | 10 ++++++----
 compiler/rustc_parse/src/parser/expr.rs       | 11 ++++++-----
 compiler/rustc_parse/src/parser/pat.rs        |  2 +-
 src/tools/rustfmt/src/attr.rs                 | 12 +++++++-----
 9 files changed, 56 insertions(+), 23 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index b869b2f8af9..c1795be2290 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -1733,8 +1733,10 @@ pub enum StrStyle {
 /// A literal in a meta item.
 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct MetaItemLit {
-    /// The original literal token as written in source code.
-    pub token_lit: token::Lit,
+    /// The original literal as written in the source code.
+    pub symbol: Symbol,
+    /// The original suffix as written in the source code.
+    pub suffix: Option<Symbol>,
     /// The "semantic" representation of the literal lowered from the original tokens.
     /// Strings are unescaped, hexadecimal forms are eliminated, etc.
     pub kind: LitKind,
@@ -3103,7 +3105,7 @@ mod size_asserts {
     static_assert_size!(ItemKind, 112);
     static_assert_size!(LitKind, 24);
     static_assert_size!(Local, 72);
-    static_assert_size!(MetaItemLit, 48);
+    static_assert_size!(MetaItemLit, 40);
     static_assert_size!(Param, 40);
     static_assert_size!(Pat, 88);
     static_assert_size!(Path, 24);
diff --git a/compiler/rustc_ast/src/attr/mod.rs b/compiler/rustc_ast/src/attr/mod.rs
index 1ba46914675..2ec126715e7 100644
--- a/compiler/rustc_ast/src/attr/mod.rs
+++ b/compiler/rustc_ast/src/attr/mod.rs
@@ -328,7 +328,9 @@ pub fn mk_name_value_item_str(ident: Ident, str: Symbol, str_span: Span) -> Meta
 }
 
 pub fn mk_name_value_item(ident: Ident, kind: LitKind, lit_span: Span) -> MetaItem {
-    let lit = MetaItemLit { token_lit: kind.synthesize_token_lit(), kind, span: lit_span };
+    let token_lit = kind.synthesize_token_lit();
+    let lit =
+        MetaItemLit { symbol: token_lit.symbol, suffix: token_lit.suffix, kind, span: lit_span };
     let span = ident.span.to(lit_span);
     MetaItem { path: Path::from_ident(ident), kind: MetaItemKind::NameValue(lit), span }
 }
diff --git a/compiler/rustc_ast/src/util/literal.rs b/compiler/rustc_ast/src/util/literal.rs
index 9f6fdf44ac0..a0a925d4700 100644
--- a/compiler/rustc_ast/src/util/literal.rs
+++ b/compiler/rustc_ast/src/util/literal.rs
@@ -202,9 +202,32 @@ impl LitKind {
 }
 
 impl MetaItemLit {
-    /// Converts token literal into a meta item literal.
+    /// Converts a token literal into a meta item literal.
     pub fn from_token_lit(token_lit: token::Lit, span: Span) -> Result<MetaItemLit, LitError> {
-        Ok(MetaItemLit { token_lit, kind: LitKind::from_token_lit(token_lit)?, span })
+        Ok(MetaItemLit {
+            symbol: token_lit.symbol,
+            suffix: token_lit.suffix,
+            kind: LitKind::from_token_lit(token_lit)?,
+            span,
+        })
+    }
+
+    /// Cheaply converts a meta item literal into a token literal.
+    pub fn as_token_lit(&self) -> token::Lit {
+        let kind = match self.kind {
+            LitKind::Bool(_) => token::Bool,
+            LitKind::Str(_, ast::StrStyle::Cooked) => token::Str,
+            LitKind::Str(_, ast::StrStyle::Raw(n)) => token::StrRaw(n),
+            LitKind::ByteStr(_, ast::StrStyle::Cooked) => token::ByteStr,
+            LitKind::ByteStr(_, ast::StrStyle::Raw(n)) => token::ByteStrRaw(n),
+            LitKind::Byte(_) => token::Byte,
+            LitKind::Char(_) => token::Char,
+            LitKind::Int(..) => token::Integer,
+            LitKind::Float(..) => token::Float,
+            LitKind::Err => token::Err,
+        };
+
+        token::Lit::new(kind, self.symbol, self.suffix)
     }
 
     /// Converts an arbitrary token into meta item literal.
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 1d279706278..8e4bfb71336 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -954,7 +954,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     lit
                 } else {
                     MetaItemLit {
-                        token_lit: token::Lit::new(token::LitKind::Err, kw::Empty, None),
+                        symbol: kw::Empty,
+                        suffix: None,
                         kind: LitKind::Err,
                         span: DUMMY_SP,
                     }
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index ebe55a4b771..d555cf48730 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -376,7 +376,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     }
 
     fn print_meta_item_lit(&mut self, lit: &ast::MetaItemLit) {
-        self.print_token_literal(lit.token_lit, lit.span)
+        self.print_token_literal(lit.as_token_lit(), lit.span)
     }
 
     fn print_token_literal(&mut self, token_lit: token::Lit, span: Span) {
diff --git a/compiler/rustc_builtin_macros/src/derive.rs b/compiler/rustc_builtin_macros/src/derive.rs
index fa5a45730ac..2a8dc02849e 100644
--- a/compiler/rustc_builtin_macros/src/derive.rs
+++ b/compiler/rustc_builtin_macros/src/derive.rs
@@ -1,7 +1,7 @@
 use crate::cfg_eval::cfg_eval;
 
 use rustc_ast as ast;
-use rustc_ast::{token, GenericParamKind, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
+use rustc_ast::{GenericParamKind, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, Indeterminate, MultiItemModifier};
 use rustc_feature::AttributeTemplate;
@@ -130,9 +130,11 @@ fn report_bad_target(sess: &Session, item: &Annotatable, span: Span) -> bool {
 }
 
 fn report_unexpected_meta_item_lit(sess: &Session, lit: &ast::MetaItemLit) {
-    let help_msg = match lit.token_lit.kind {
-        token::Str if rustc_lexer::is_ident(lit.token_lit.symbol.as_str()) => {
-            format!("try using `#[derive({})]`", lit.token_lit.symbol)
+    let help_msg = match lit.kind {
+        ast::LitKind::Str(_, ast::StrStyle::Cooked)
+            if rustc_lexer::is_ident(lit.symbol.as_str()) =>
+        {
+            format!("try using `#[derive({})]`", lit.symbol)
         }
         _ => "for example, write `#[derive(Debug)]` for `Debug`".to_string(),
     };
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index e0443a697b5..1c773bea000 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1551,7 +1551,7 @@ impl<'a> Parser<'a> {
                 })
             });
             consume_colon = false;
-            Ok(self.mk_expr(lo, ExprKind::Lit(lit.token_lit)))
+            Ok(self.mk_expr(lo, ExprKind::Lit(lit.as_token_lit())))
         } else if !ate_colon
             && (self.check_noexpect(&TokenKind::Comma) || self.check_noexpect(&TokenKind::Gt))
         {
@@ -1654,7 +1654,8 @@ impl<'a> Parser<'a> {
         }
         let name = lifetime.without_first_quote().name;
         ast::MetaItemLit {
-            token_lit: token::Lit::new(token::LitKind::Char, name, None),
+            symbol: name,
+            suffix: None,
             kind: ast::LitKind::Char(name.as_str().chars().next().unwrap_or('_')),
             span: lifetime.span,
         }
@@ -1773,8 +1774,8 @@ impl<'a> Parser<'a> {
             Some(lit) => match lit.kind {
                 ast::LitKind::Str(symbol_unescaped, style) => Ok(ast::StrLit {
                     style,
-                    symbol: lit.token_lit.symbol,
-                    suffix: lit.token_lit.suffix,
+                    symbol: lit.symbol,
+                    suffix: lit.suffix,
                     span: lit.span,
                     symbol_unescaped,
                 }),
@@ -1817,7 +1818,7 @@ impl<'a> Parser<'a> {
     pub(super) fn parse_token_lit(&mut self) -> PResult<'a, (token::Lit, Span)> {
         self.parse_opt_token_lit()
             .ok_or(())
-            .or_else(|()| self.handle_missing_lit().map(|lit| (lit.token_lit, lit.span)))
+            .or_else(|()| self.handle_missing_lit().map(|lit| (lit.as_token_lit(), lit.span)))
     }
 
     pub(super) fn parse_meta_item_lit(&mut self) -> PResult<'a, MetaItemLit> {
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index cbeec951e2d..b5147158f70 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -420,7 +420,7 @@ impl<'a> Parser<'a> {
                 err.span_label(self_.token.span, format!("expected {}", expected));
                 err
             });
-            PatKind::Lit(self.mk_expr(lo, ExprKind::Lit(lit.token_lit)))
+            PatKind::Lit(self.mk_expr(lo, ExprKind::Lit(lit.as_token_lit())))
         } else {
             // Try to parse everything else as literal with optional minus
             match self.parse_literal_maybe_minus() {
diff --git a/src/tools/rustfmt/src/attr.rs b/src/tools/rustfmt/src/attr.rs
index 2ac703b957b..c503eeeb9b3 100644
--- a/src/tools/rustfmt/src/attr.rs
+++ b/src/tools/rustfmt/src/attr.rs
@@ -260,7 +260,9 @@ impl Rewrite for ast::NestedMetaItem {
     fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> {
         match self {
             ast::NestedMetaItem::MetaItem(ref meta_item) => meta_item.rewrite(context, shape),
-            ast::NestedMetaItem::Lit(ref l) => rewrite_literal(context, l.token_lit, l.span, shape),
+            ast::NestedMetaItem::Lit(ref l) => {
+                rewrite_literal(context, l.as_token_lit(), l.span, shape)
+            }
         }
     }
 }
@@ -308,18 +310,18 @@ impl Rewrite for ast::MetaItem {
                     }),
                 )?
             }
-            ast::MetaItemKind::NameValue(ref literal) => {
+            ast::MetaItemKind::NameValue(ref lit) => {
                 let path = rewrite_path(context, PathContext::Type, &None, &self.path, shape)?;
                 // 3 = ` = `
                 let lit_shape = shape.shrink_left(path.len() + 3)?;
-                // `rewrite_literal` returns `None` when `literal` exceeds max
+                // `rewrite_literal` returns `None` when `lit` exceeds max
                 // width. Since a literal is basically unformattable unless it
                 // is a string literal (and only if `format_strings` is set),
                 // we might be better off ignoring the fact that the attribute
                 // is longer than the max width and continue on formatting.
                 // See #2479 for example.
-                let value = rewrite_literal(context, literal.token_lit, literal.span, lit_shape)
-                    .unwrap_or_else(|| context.snippet(literal.span).to_owned());
+                let value = rewrite_literal(context, lit.as_token_lit(), lit.span, lit_shape)
+                    .unwrap_or_else(|| context.snippet(lit.span).to_owned());
                 format!("{} = {}", path, value)
             }
         })
-- 
cgit 1.4.1-3-g733a5


From d887615b4c83d856cd3e40000968c047f2ff4019 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Mon, 5 Dec 2022 14:39:56 +1100
Subject: Parameterise `Parser::{recover_unclosed_char,handle_missing_lit}`.

These two methods both produce a `MetaItemLit`, and then some of the
call sites convert the `MetaItemLit` to a `token::Lit` with
`as_token_lit`.

This commit parameterises these two methods with a `mk_lit_char`
closure, which can be used to produce either `MetaItemLit` or
`token::Lit` directly as necessary.
---
 compiler/rustc_parse/src/parser/expr.rs | 57 +++++++++++++++++++++------------
 compiler/rustc_parse/src/parser/pat.rs  | 22 +++++++------
 2 files changed, 49 insertions(+), 30 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 1c773bea000..07f03e0d582 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1543,15 +1543,16 @@ impl<'a> Parser<'a> {
             && (matches!(self.token.kind, token::CloseDelim(_) | token::Comma)
                 || self.token.is_op())
         {
-            let lit = self.recover_unclosed_char(label_.ident, |self_| {
-                self_.sess.create_err(UnexpectedTokenAfterLabel {
-                    span: self_.token.span,
-                    remove_label: None,
-                    enclose_in_block: None,
-                })
-            });
+            let (lit, _) =
+                self.recover_unclosed_char(label_.ident, Parser::mk_token_lit_char, |self_| {
+                    self_.sess.create_err(UnexpectedTokenAfterLabel {
+                        span: self_.token.span,
+                        remove_label: None,
+                        enclose_in_block: None,
+                    })
+                });
             consume_colon = false;
-            Ok(self.mk_expr(lo, ExprKind::Lit(lit.as_token_lit())))
+            Ok(self.mk_expr(lo, ExprKind::Lit(lit)))
         } else if !ate_colon
             && (self.check_noexpect(&TokenKind::Comma) || self.check_noexpect(&TokenKind::Gt))
         {
@@ -1626,12 +1627,13 @@ impl<'a> Parser<'a> {
         Ok(expr)
     }
 
-    /// Emit an error when a char is parsed as a lifetime because of a missing quote
-    pub(super) fn recover_unclosed_char(
+    /// Emit an error when a char is parsed as a lifetime because of a missing quote.
+    pub(super) fn recover_unclosed_char<L>(
         &self,
         lifetime: Ident,
+        mk_lit_char: impl FnOnce(Symbol, Span) -> L,
         err: impl FnOnce(&Self) -> DiagnosticBuilder<'a, ErrorGuaranteed>,
-    ) -> ast::MetaItemLit {
+    ) -> L {
         if let Some(mut diag) =
             self.sess.span_diagnostic.steal_diagnostic(lifetime.span, StashKey::LifetimeIsChar)
         {
@@ -1653,12 +1655,7 @@ impl<'a> Parser<'a> {
                 .emit();
         }
         let name = lifetime.without_first_quote().name;
-        ast::MetaItemLit {
-            symbol: name,
-            suffix: None,
-            kind: ast::LitKind::Char(name.as_str().chars().next().unwrap_or('_')),
-            span: lifetime.span,
-        }
+        mk_lit_char(name, lifetime.span)
     }
 
     /// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.
@@ -1785,7 +1782,23 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn handle_missing_lit(&mut self) -> PResult<'a, MetaItemLit> {
+    pub(crate) fn mk_token_lit_char(name: Symbol, span: Span) -> (token::Lit, Span) {
+        (token::Lit { symbol: name, suffix: None, kind: token::Char }, span)
+    }
+
+    fn mk_meta_item_lit_char(name: Symbol, span: Span) -> MetaItemLit {
+        ast::MetaItemLit {
+            symbol: name,
+            suffix: None,
+            kind: ast::LitKind::Char(name.as_str().chars().next().unwrap_or('_')),
+            span,
+        }
+    }
+
+    fn handle_missing_lit<L>(
+        &mut self,
+        mk_lit_char: impl FnOnce(Symbol, Span) -> L,
+    ) -> PResult<'a, L> {
         if let token::Interpolated(inner) = &self.token.kind {
             let expr = match inner.as_ref() {
                 token::NtExpr(expr) => Some(expr),
@@ -1809,7 +1822,7 @@ impl<'a> Parser<'a> {
         // On an error path, eagerly consider a lifetime to be an unclosed character lit
         if self.token.is_lifetime() {
             let lt = self.expect_lifetime();
-            Ok(self.recover_unclosed_char(lt.ident, err))
+            Ok(self.recover_unclosed_char(lt.ident, mk_lit_char, err))
         } else {
             Err(err(self))
         }
@@ -1818,11 +1831,13 @@ impl<'a> Parser<'a> {
     pub(super) fn parse_token_lit(&mut self) -> PResult<'a, (token::Lit, Span)> {
         self.parse_opt_token_lit()
             .ok_or(())
-            .or_else(|()| self.handle_missing_lit().map(|lit| (lit.as_token_lit(), lit.span)))
+            .or_else(|()| self.handle_missing_lit(Parser::mk_token_lit_char))
     }
 
     pub(super) fn parse_meta_item_lit(&mut self) -> PResult<'a, MetaItemLit> {
-        self.parse_opt_meta_item_lit().ok_or(()).or_else(|()| self.handle_missing_lit())
+        self.parse_opt_meta_item_lit()
+            .ok_or(())
+            .or_else(|()| self.handle_missing_lit(Parser::mk_meta_item_lit_char))
     }
 
     fn recover_after_dot(&mut self) -> Option<Token> {
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index b5147158f70..a1981e11477 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -411,16 +411,20 @@ impl<'a> Parser<'a> {
         {
             // Recover a `'a` as a `'a'` literal
             let lt = self.expect_lifetime();
-            let lit = self.recover_unclosed_char(lt.ident, |self_| {
-                let expected = expected.unwrap_or("pattern");
-                let msg =
-                    format!("expected {}, found {}", expected, super::token_descr(&self_.token));
+            let (lit, _) =
+                self.recover_unclosed_char(lt.ident, Parser::mk_token_lit_char, |self_| {
+                    let expected = expected.unwrap_or("pattern");
+                    let msg = format!(
+                        "expected {}, found {}",
+                        expected,
+                        super::token_descr(&self_.token)
+                    );
 
-                let mut err = self_.struct_span_err(self_.token.span, &msg);
-                err.span_label(self_.token.span, format!("expected {}", expected));
-                err
-            });
-            PatKind::Lit(self.mk_expr(lo, ExprKind::Lit(lit.as_token_lit())))
+                    let mut err = self_.struct_span_err(self_.token.span, &msg);
+                    err.span_label(self_.token.span, format!("expected {}", expected));
+                    err
+                });
+            PatKind::Lit(self.mk_expr(lo, ExprKind::Lit(lit)))
         } else {
             // Try to parse everything else as literal with optional minus
             match self.parse_literal_maybe_minus() {
-- 
cgit 1.4.1-3-g733a5


From 5599f2ad09345b94487920b84029ad215c4dc743 Mon Sep 17 00:00:00 2001
From: yukang <moorekang@gmail.com>
Date: Tue, 6 Dec 2022 21:00:38 +0800
Subject: fix #105226, Detect spurious ; before assoc fn body

---
 compiler/rustc_parse/src/parser/item.rs     | 12 ++++++++---
 src/test/ui/suggestions/issue-105226.rs     | 22 ++++++++++++++++++++
 src/test/ui/suggestions/issue-105226.stderr | 31 +++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 3 deletions(-)
 create mode 100644 src/test/ui/suggestions/issue-105226.rs
 create mode 100644 src/test/ui/suggestions/issue-105226.stderr

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 84c63219920..8f4f68fb067 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -707,9 +707,9 @@ impl<'a> Parser<'a> {
             }
             match parse_item(self) {
                 Ok(None) => {
-                    let is_unnecessary_semicolon = !items.is_empty()
+                    let mut is_unnecessary_semicolon = !items.is_empty()
                         // When the close delim is `)` in a case like the following, `token.kind` is expected to be `token::CloseDelim(Delimiter::Parenthesis)`,
-                        // but the actual `token.kind` is `token::CloseDelim(Delimiter::Bracket)`.
+                        // but the actual `token.kind` is `token::CloseDelim(Delimiter::Brace)`.
                         // This is because the `token.kind` of the close delim is treated as the same as
                         // that of the open delim in `TokenTreesReader::parse_token_tree`, even if the delimiters of them are different.
                         // Therefore, `token.kind` should not be compared here.
@@ -728,7 +728,13 @@ impl<'a> Parser<'a> {
                             .span_to_snippet(self.prev_token.span)
                             .map_or(false, |snippet| snippet == "}")
                         && self.token.kind == token::Semi;
-                    let semicolon_span = self.token.span;
+                    let mut semicolon_span = self.token.span;
+                    if !is_unnecessary_semicolon {
+                        // #105369, Detect spurious `;` before assoc fn body
+                        is_unnecessary_semicolon = self.token == token::OpenDelim(Delimiter::Brace)
+                            && self.prev_token.kind == token::Semi;
+                        semicolon_span = self.prev_token.span;
+                    }
                     // We have to bail or we'll potentially never make progress.
                     let non_item_span = self.token.span;
                     let is_let = self.token.is_keyword(kw::Let);
diff --git a/src/test/ui/suggestions/issue-105226.rs b/src/test/ui/suggestions/issue-105226.rs
new file mode 100644
index 00000000000..f123dbf4cae
--- /dev/null
+++ b/src/test/ui/suggestions/issue-105226.rs
@@ -0,0 +1,22 @@
+use std::fmt;
+
+struct S {
+}
+
+impl S {
+    fn hello<P>(&self, val: &P) where P: fmt::Display; {
+        //~^ ERROR non-item in item list
+        //~| ERROR associated function in `impl` without body
+        println!("val: {}", val);
+    }
+}
+
+impl S {
+    fn hello_empty<P>(&self, val: &P) where P: fmt::Display;
+    //~^ ERROR associated function in `impl` without body
+}
+
+fn main() {
+    let s = S{};
+    s.hello(&32);
+}
diff --git a/src/test/ui/suggestions/issue-105226.stderr b/src/test/ui/suggestions/issue-105226.stderr
new file mode 100644
index 00000000000..f16a8090103
--- /dev/null
+++ b/src/test/ui/suggestions/issue-105226.stderr
@@ -0,0 +1,31 @@
+error: non-item in item list
+  --> $DIR/issue-105226.rs:7:56
+   |
+LL | impl S {
+   |        - item list starts here
+LL |     fn hello<P>(&self, val: &P) where P: fmt::Display; {
+   |                                                      - ^ non-item starts here
+   |                                                      |
+   |                                                      help: consider removing this semicolon
+...
+LL | }
+   | - item list ends here
+
+error: associated function in `impl` without body
+  --> $DIR/issue-105226.rs:7:5
+   |
+LL |     fn hello<P>(&self, val: &P) where P: fmt::Display; {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
+   |                                                      |
+   |                                                      help: provide a definition for the function: `{ <body> }`
+
+error: associated function in `impl` without body
+  --> $DIR/issue-105226.rs:15:5
+   |
+LL |     fn hello_empty<P>(&self, val: &P) where P: fmt::Display;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
+   |                                                            |
+   |                                                            help: provide a definition for the function: `{ <body> }`
+
+error: aborting due to 3 previous errors
+
-- 
cgit 1.4.1-3-g733a5


From 9bc69925cb4a1391a9a41411c56ae059877bf8fb Mon Sep 17 00:00:00 2001
From: KaDiWa <kalle.wachsmuth@gmail.com>
Date: Tue, 9 Aug 2022 02:14:43 +0200
Subject: compiler: remove unnecessary imports and qualified paths

---
 compiler/rustc_abi/src/lib.rs                                      | 1 -
 compiler/rustc_apfloat/src/ieee.rs                                 | 1 -
 compiler/rustc_arena/src/lib.rs                                    | 2 +-
 compiler/rustc_ast/src/ast.rs                                      | 1 -
 compiler/rustc_ast/src/ptr.rs                                      | 1 -
 compiler/rustc_ast/src/tokenstream.rs                              | 2 +-
 compiler/rustc_ast_lowering/src/lib.rs                             | 4 ++--
 compiler/rustc_builtin_macros/src/concat.rs                        | 2 --
 compiler/rustc_codegen_ssa/src/base.rs                             | 1 -
 compiler/rustc_const_eval/src/const_eval/eval_queries.rs           | 1 -
 compiler/rustc_const_eval/src/interpret/cast.rs                    | 1 -
 compiler/rustc_const_eval/src/interpret/intrinsics.rs              | 2 --
 .../rustc_const_eval/src/interpret/intrinsics/caller_location.rs   | 2 --
 compiler/rustc_const_eval/src/interpret/operator.rs                | 2 --
 compiler/rustc_const_eval/src/interpret/util.rs                    | 1 -
 compiler/rustc_const_eval/src/interpret/validity.rs                | 1 -
 compiler/rustc_const_eval/src/util/aggregate.rs                    | 1 -
 compiler/rustc_data_structures/src/fingerprint.rs                  | 1 -
 compiler/rustc_data_structures/src/graph/scc/mod.rs                | 1 -
 compiler/rustc_data_structures/src/graph/vec_graph/mod.rs          | 2 --
 compiler/rustc_data_structures/src/owning_ref/mod.rs               | 5 +----
 compiler/rustc_data_structures/src/owning_ref/tests.rs             | 4 ++--
 compiler/rustc_data_structures/src/profiling.rs                    | 1 -
 compiler/rustc_data_structures/src/sorted_map.rs                   | 1 -
 compiler/rustc_data_structures/src/sorted_map/index_map.rs         | 1 -
 compiler/rustc_data_structures/src/sso/either_iter.rs              | 2 --
 compiler/rustc_data_structures/src/sso/map.rs                      | 1 -
 compiler/rustc_data_structures/src/sso/set.rs                      | 1 -
 compiler/rustc_data_structures/src/sync.rs                         | 2 +-
 compiler/rustc_data_structures/src/tagged_ptr/drop.rs              | 2 +-
 compiler/rustc_data_structures/src/vec_map.rs                      | 1 -
 compiler/rustc_driver/src/lib.rs                                   | 1 -
 compiler/rustc_error_codes/src/error_codes/E0492.md                | 1 -
 compiler/rustc_errors/src/diagnostic_impls.rs                      | 2 +-
 compiler/rustc_expand/src/base.rs                                  | 1 -
 compiler/rustc_hir/src/pat_util.rs                                 | 2 +-
 compiler/rustc_hir_analysis/src/check/wfcheck.rs                   | 1 -
 compiler/rustc_incremental/src/persist/dirty_clean.rs              | 2 --
 compiler/rustc_incremental/src/persist/fs.rs                       | 7 +++----
 compiler/rustc_index/src/vec.rs                                    | 1 -
 compiler/rustc_interface/src/tests.rs                              | 1 -
 compiler/rustc_lexer/src/lib.rs                                    | 1 -
 compiler/rustc_lint/src/types.rs                                   | 3 +--
 compiler/rustc_metadata/src/rmeta/table.rs                         | 1 -
 compiler/rustc_middle/src/mir/coverage.rs                          | 1 -
 compiler/rustc_middle/src/mir/interpret/mod.rs                     | 1 -
 compiler/rustc_middle/src/mir/interpret/pointer.rs                 | 1 -
 compiler/rustc_middle/src/mir/interpret/value.rs                   | 1 -
 compiler/rustc_middle/src/mir/mod.rs                               | 1 -
 compiler/rustc_middle/src/traits/query.rs                          | 1 -
 compiler/rustc_middle/src/ty/consts/int.rs                         | 1 -
 compiler/rustc_middle/src/ty/consts/kind.rs                        | 2 --
 compiler/rustc_middle/src/ty/print/pretty.rs                       | 1 -
 compiler/rustc_middle/src/ty/vtable.rs                             | 1 -
 compiler/rustc_mir_build/src/build/matches/mod.rs                  | 1 -
 compiler/rustc_mir_build/src/build/matches/util.rs                 | 1 -
 compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs       | 2 +-
 compiler/rustc_mir_dataflow/src/framework/lattice.rs               | 2 +-
 compiler/rustc_mir_transform/src/simplify.rs                       | 1 -
 compiler/rustc_monomorphize/src/polymorphize.rs                    | 1 -
 compiler/rustc_parse/src/parser/attr.rs                            | 1 -
 compiler/rustc_parse/src/parser/attr_wrapper.rs                    | 1 -
 compiler/rustc_parse/src/parser/item.rs                            | 1 -
 compiler/rustc_query_system/src/dep_graph/graph.rs                 | 2 +-
 compiler/rustc_query_system/src/dep_graph/serialized.rs            | 1 -
 compiler/rustc_query_system/src/query/caches.rs                    | 1 -
 compiler/rustc_query_system/src/query/job.rs                       | 6 +++---
 compiler/rustc_save_analysis/src/lib.rs                            | 1 -
 compiler/rustc_serialize/src/opaque.rs                             | 1 -
 compiler/rustc_session/src/config.rs                               | 2 +-
 compiler/rustc_session/src/filesearch.rs                           | 1 -
 compiler/rustc_span/src/source_map.rs                              | 3 +--
 compiler/rustc_span/src/symbol.rs                                  | 2 --
 compiler/rustc_target/src/lib.rs                                   | 1 -
 compiler/rustc_target/src/spec/mod.rs                              | 2 --
 compiler/rustc_type_ir/src/sty.rs                                  | 2 +-
 76 files changed, 24 insertions(+), 98 deletions(-)

(limited to 'compiler/rustc_parse/src/parser')

diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs
index e14c9ea9a5d..4ca59144b29 100644
--- a/compiler/rustc_abi/src/lib.rs
+++ b/compiler/rustc_abi/src/lib.rs
@@ -1,6 +1,5 @@
 #![cfg_attr(feature = "nightly", feature(step_trait, rustc_attrs, min_specialization))]
 
-use std::convert::{TryFrom, TryInto};
 use std::fmt;
 #[cfg(feature = "nightly")]
 use std::iter::Step;
diff --git a/compiler/rustc_apfloat/src/ieee.rs b/compiler/rustc_apfloat/src/ieee.rs
index 3db8adb2a24..2286712f025 100644
--- a/compiler/rustc_apfloat/src/ieee.rs
+++ b/compiler/rustc_apfloat/src/ieee.rs
@@ -2,7 +2,6 @@ use crate::{Category, ExpInt, IEK_INF, IEK_NAN, IEK_ZERO};
 use crate::{Float, FloatConvert, ParseError, Round, Status, StatusAnd};
 
 use core::cmp::{self, Ordering};
-use core::convert::TryFrom;
 use core::fmt::{self, Write};
 use core::marker::PhantomData;
 use core::mem;
diff --git a/compiler/rustc_arena/src/lib.rs b/compiler/rustc_arena/src/lib.rs
index 46dbbd83d19..4fae5ef845f 100644
--- a/compiler/rustc_arena/src/lib.rs
+++ b/compiler/rustc_arena/src/lib.rs
@@ -28,7 +28,7 @@ use smallvec::SmallVec;
 use std::alloc::Layout;
 use std::cell::{Cell, RefCell};
 use std::cmp;
-use std::marker::{PhantomData, Send};
+use std::marker::PhantomData;
 use std::mem::{self, MaybeUninit};
 use std::ptr::{self, NonNull};
 use std::slice;
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 4d80f904ac4..74a0c13b23f 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -33,7 +33,6 @@ use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use std::convert::TryFrom;
 use std::fmt;
 use std::mem;
 use thin_vec::{thin_vec, ThinVec};
diff --git a/compiler/rustc_ast/src/ptr.rs b/compiler/rustc_ast/src/ptr.rs
index 30481eddf91..4b2850336a0 100644
--- a/compiler/rustc_ast/src/ptr.rs
+++ b/compiler/rustc_ast/src/ptr.rs
@@ -22,7 +22,6 @@
 //!   Moreover, a switch to, e.g., `P<'a, T>` would be easy and mostly automated.
 
 use std::fmt::{self, Debug, Display};
-use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};
 use std::{slice, vec};
 
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 482c302950f..29a5eb4b7c5 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -362,7 +362,7 @@ impl TokenStream {
     }
 }
 
-impl iter::FromIterator<TokenTree> for TokenStream {
+impl FromIterator<TokenTree> for TokenStream {
     fn from_iter<I: IntoIterator<Item = TokenTree>>(iter: I) -> Self {
         TokenStream::new(iter.into_iter().collect::<Vec<TokenTree>>())
     }
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 4fa18907fcd..5d7397977e9 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -456,8 +456,8 @@ pub fn lower_to_hir<'hir>(tcx: TyCtxt<'hir>, (): ()) -> hir::Crate<'hir> {
     }
 
     // Drop AST to free memory
-    std::mem::drop(ast_index);
-    sess.time("drop_ast", || std::mem::drop(krate));
+    drop(ast_index);
+    sess.time("drop_ast", || drop(krate));
 
     // Discard hygiene data, which isn't required after lowering to HIR.
     if !sess.opts.unstable_opts.keep_hygiene_data {
diff --git a/compiler/rustc_builtin_macros/src/concat.rs b/compiler/rustc_builtin_macros/src/concat.rs
index e2d71825d55..c9dc6b847cd 100644
--- a/compiler/rustc_builtin_macros/src/concat.rs
+++ b/compiler/rustc_builtin_macros/src/concat.rs
@@ -4,8 +4,6 @@ use rustc_expand::base::{self, DummyResult};
 use rustc_session::errors::report_lit_error;
 use rustc_span::symbol::Symbol;
 
-use std::string::String;
-
 pub fn expand_concat(
     cx: &mut base::ExtCtxt<'_>,
     sp: rustc_span::Span,
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 4f396e970ad..664697e0eda 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -41,7 +41,6 @@ use rustc_span::{DebuggerVisualizerFile, DebuggerVisualizerType};
 use rustc_target::abi::{Align, Size, VariantIdx};
 
 use std::collections::BTreeSet;
-use std::convert::TryFrom;
 use std::time::{Duration, Instant};
 
 use itertools::Itertools;
diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
index c27790d8887..319f2b2c25e 100644
--- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
+++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs
@@ -1,5 +1,4 @@
 use std::borrow::Cow;
-use std::convert::TryInto;
 
 use either::{Left, Right};
 
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index 269ae15d497..b1fdeb01b10 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -1,5 +1,4 @@
 use std::assert_matches::assert_matches;
-use std::convert::TryFrom;
 
 use rustc_apfloat::ieee::{Double, Single};
 use rustc_apfloat::{Float, FloatConvert};
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index 7940efcd2b1..b9be7fa4800 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -2,8 +2,6 @@
 //! looking at their MIR. Intrinsics/functions supported here are shared by CTFE
 //! and miri.
 
-use std::convert::TryFrom;
-
 use rustc_hir::def_id::DefId;
 use rustc_middle::mir::{
     self,
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
index 7d94a22c43d..77c7b4bacb8 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs
@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-
 use rustc_ast::Mutability;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::mir::TerminatorKind;
diff --git a/compiler/rustc_const_eval/src/interpret/operator.rs b/compiler/rustc_const_eval/src/interpret/operator.rs
index 1f1d0665139..949f95c5fa8 100644
--- a/compiler/rustc_const_eval/src/interpret/operator.rs
+++ b/compiler/rustc_const_eval/src/interpret/operator.rs
@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-
 use rustc_apfloat::Float;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{InterpResult, Scalar};
diff --git a/compiler/rustc_const_eval/src/interpret/util.rs b/compiler/rustc_const_eval/src/interpret/util.rs
index 2bc521d5bbe..e4f716c3194 100644
--- a/compiler/rustc_const_eval/src/interpret/util.rs
+++ b/compiler/rustc_const_eval/src/interpret/util.rs
@@ -1,6 +1,5 @@
 use rustc_middle::mir::interpret::InterpResult;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor};
-use std::convert::TryInto;
 use std::ops::ControlFlow;
 
 /// Checks whether a type contains generic parameters which require substitution.
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 0e85c7d11bc..fc65306e440 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -4,7 +4,6 @@
 //! That's useful because it means other passes (e.g. promotion) can rely on `const`s
 //! to be const-safe.
 
-use std::convert::TryFrom;
 use std::fmt::{Display, Write};
 use std::num::NonZeroUsize;
 
diff --git a/compiler/rustc_const_eval/src/util/aggregate.rs b/compiler/rustc_const_eval/src/util/aggregate.rs
index c43de3368c6..10783c5ed1d 100644
--- a/compiler/rustc_const_eval/src/util/aggregate.rs
+++ b/compiler/rustc_const_eval/src/util/aggregate.rs
@@ -3,7 +3,6 @@ use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
 use rustc_target::abi::VariantIdx;
 
-use std::convert::TryFrom;
 use std::iter::TrustedLen;
 
 /// Expand `lhs = Rvalue::Aggregate(kind, operands)` into assignments to the fields.
diff --git a/compiler/rustc_data_structures/src/fingerprint.rs b/compiler/rustc_data_structures/src/fingerprint.rs
index d98f4e43fe8..b6e866f15ef 100644
--- a/compiler/rustc_data_structures/src/fingerprint.rs
+++ b/compiler/rustc_data_structures/src/fingerprint.rs
@@ -1,6 +1,5 @@
 use crate::stable_hasher;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
-use std::convert::TryInto;
 use std::hash::{Hash, Hasher};
 
 #[cfg(test)]
diff --git a/compiler/rustc_data_structures/src/graph/scc/mod.rs b/compiler/rustc_data_structures/src/graph/scc/mod.rs
index 7099ca7eb88..b31092eca98 100644
--- a/compiler/rustc_data_structures/src/graph/scc/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/scc/mod.rs
@@ -9,7 +9,6 @@ use crate::fx::FxHashSet;
 use crate::graph::vec_graph::VecGraph;
 use crate::graph::{DirectedGraph, GraphSuccessors, WithNumEdges, WithNumNodes, WithSuccessors};
 use rustc_index::vec::{Idx, IndexVec};
-use std::cmp::Ord;
 use std::ops::Range;
 
 #[cfg(test)]
diff --git a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
index e8efbd09a2c..94232bb7626 100644
--- a/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/vec_graph/mod.rs
@@ -1,5 +1,3 @@
-use std::cmp::Ord;
-
 use crate::graph::{DirectedGraph, GraphSuccessors, WithNumEdges, WithNumNodes, WithSuccessors};
 use rustc_index::vec::{Idx, IndexVec};
 
diff --git a/compiler/rustc_data_structures/src/owning_ref/mod.rs b/compiler/rustc_data_structures/src/owning_ref/mod.rs
index 980a540ccba..d1d92b905b8 100644
--- a/compiler/rustc_data_structures/src/owning_ref/mod.rs
+++ b/compiler/rustc_data_structures/src/owning_ref/mod.rs
@@ -867,11 +867,9 @@ where
 /////////////////////////////////////////////////////////////////////////////
 
 use std::borrow::Borrow;
-use std::cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd};
-use std::convert::From;
+use std::cmp::Ordering;
 use std::fmt::{self, Debug};
 use std::hash::{Hash, Hasher};
-use std::marker::{Send, Sync};
 
 impl<O, T: ?Sized> Deref for OwningRef<O, T> {
     type Target = T;
@@ -1096,7 +1094,6 @@ where
 // std types integration and convenience type defs
 /////////////////////////////////////////////////////////////////////////////
 
-use std::boxed::Box;
 use std::cell::{Ref, RefCell, RefMut};
 use std::rc::Rc;
 use std::sync::Arc;
diff --git a/compiler/rustc_data_structures/src/owning_ref/tests.rs b/compiler/rustc_data_structures/src/owning_ref/tests.rs
index 320c03d5139..a9b187c4ce0 100644
--- a/compiler/rustc_data_structures/src/owning_ref/tests.rs
+++ b/compiler/rustc_data_structures/src/owning_ref/tests.rs
@@ -3,7 +3,7 @@
 mod owning_ref {
     use super::super::OwningRef;
     use super::super::{BoxRef, Erased, ErasedBoxRef, RcRef};
-    use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
+    use std::cmp::Ordering;
     use std::collections::hash_map::DefaultHasher;
     use std::collections::HashMap;
     use std::hash::{Hash, Hasher};
@@ -368,7 +368,7 @@ mod owning_handle {
 mod owning_ref_mut {
     use super::super::BoxRef;
     use super::super::{BoxRefMut, Erased, ErasedBoxRefMut, OwningRefMut};
-    use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
+    use std::cmp::Ordering;
     use std::collections::hash_map::DefaultHasher;
     use std::collections::HashMap;
     use std::hash::{Hash, Hasher};
diff --git a/compiler/rustc_data_structures/src/profiling.rs b/compiler/rustc_data_structures/src/profiling.rs
index aa7a01eed15..1d4014f05ac 100644
--- a/compiler/rustc_data_structures/src/profiling.rs
+++ b/compiler/rustc_data_structures/src/profiling.rs
@@ -86,7 +86,6 @@ use crate::fx::FxHashMap;
 
 use std::borrow::Borrow;
 use std::collections::hash_map::Entry;
-use std::convert::Into;
 use std::error::Error;
 use std::fs;
 use std::path::Path;
diff --git a/compiler/rustc_data_structures/src/sorted_map.rs b/compiler/rustc_data_structures/src/sorted_map.rs
index d13313dfd0e..03ff5e5b375 100644
--- a/compiler/rustc_data_structures/src/sorted_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map.rs
@@ -1,7 +1,6 @@
 use crate::stable_hasher::{HashStable, StableHasher, StableOrd};
 use std::borrow::Borrow;
 use std::cmp::Ordering;
-use std::iter::FromIterator;
 use std::mem;
 use std::ops::{Bound, Index, IndexMut, RangeBounds};
 
diff --git a/compiler/rustc_data_structures/src/sorted_map/index_map.rs b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
index c2f0ae32896..7af5c14942a 100644
--- a/compiler/rustc_data_structures/src/sorted_map/index_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
@@ -1,7 +1,6 @@
 //! A variant of `SortedMap` that preserves insertion order.
 
 use std::hash::{Hash, Hasher};
-use std::iter::FromIterator;
 
 use crate::stable_hasher::{HashStable, StableHasher};
 use rustc_index::vec::{Idx, IndexVec};
diff --git a/compiler/rustc_data_structures/src/sso/either_iter.rs b/compiler/rustc_data_structures/src/sso/either_iter.rs
index 131eeef4582..bca6c0955b9 100644
--- a/compiler/rustc_data_structures/src/sso/either_iter.rs
+++ b/compiler/rustc_data_structures/src/sso/either_iter.rs
@@ -1,7 +1,5 @@
 use std::fmt;
-use std::iter::ExactSizeIterator;
 use std::iter::FusedIterator;
-use std::iter::Iterator;
 
 /// Iterator which may contain instance of
 /// one of two specific implementations.
diff --git a/compiler/rustc_data_structures/src/sso/map.rs b/compiler/rustc_data_structures/src/sso/map.rs
index ec6a62016a8..7cdac581977 100644
--- a/compiler/rustc_data_structures/src/sso/map.rs
+++ b/compiler/rustc_data_structures/src/sso/map.rs
@@ -3,7 +3,6 @@ use crate::fx::FxHashMap;
 use arrayvec::ArrayVec;
 use std::fmt;
 use std::hash::Hash;
-use std::iter::FromIterator;
 use std::ops::Index;
 
 // For pointer-sized arguments arrays
diff --git a/compiler/rustc_data_structures/src/sso/set.rs b/compiler/rustc_data_structures/src/sso/set.rs
index 406f0270dcc..a4b40138933 100644
--- a/compiler/rustc_data_structures/src/sso/set.rs
+++ b/compiler/rustc_data_structures/src/sso/set.rs
@@ -1,6 +1,5 @@
 use std::fmt;
 use std::hash::Hash;
-use std::iter::FromIterator;
 
 use super::map::SsoHashMap;
 
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index e4f47b22ac3..ed5341c40ef 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -138,7 +138,7 @@ cfg_if! {
             }
         }
 
-        pub use std::iter::Iterator as ParallelIterator;
+        pub use Iterator as ParallelIterator;
 
         pub fn par_iter<T: IntoIterator>(t: T) -> T::IntoIter {
             t.into_iter()
diff --git a/compiler/rustc_data_structures/src/tagged_ptr/drop.rs b/compiler/rustc_data_structures/src/tagged_ptr/drop.rs
index d44ccd368b3..b0315c93d93 100644
--- a/compiler/rustc_data_structures/src/tagged_ptr/drop.rs
+++ b/compiler/rustc_data_structures/src/tagged_ptr/drop.rs
@@ -76,7 +76,7 @@ where
     fn drop(&mut self) {
         // No need to drop the tag, as it's Copy
         unsafe {
-            std::mem::drop(P::from_usize(self.raw.pointer_raw()));
+            drop(P::from_usize(self.raw.pointer_raw()));
         }
     }
 }
diff --git a/compiler/rustc_data_structures/src/vec_map.rs b/compiler/rustc_data_structures/src/vec_map.rs
index 86be0bd8775..2417df66bb9 100644
--- a/compiler/rustc_data_structures/src/vec_map.rs
+++ b/compiler/rustc_data_structures/src/vec_map.rs
@@ -1,6 +1,5 @@
 use std::borrow::Borrow;
 use std::fmt::Debug;
-use std::iter::FromIterator;
 use std::slice::Iter;
 use std::vec::IntoIter;
 
diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index f06ca5a0733..711eed2b272 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -45,7 +45,6 @@ use rustc_target::json::ToJson;
 
 use std::borrow::Cow;
 use std::cmp::max;
-use std::default::Default;
 use std::env;
 use std::ffi::OsString;
 use std::fs;
diff --git a/compiler/rustc_error_codes/src/error_codes/E0492.md b/compiler/rustc_error_codes/src/error_codes/E0492.md
index 79e7c069a91..7c0719dc217 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0492.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0492.md
@@ -55,7 +55,6 @@ wrapper:
 
 ```
 use std::cell::Cell;
-use std::marker::Sync;
 
 struct NotThreadSafe<T> {
     value: Cell<T>,
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index 7155db32e53..88b4fffd46f 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -59,7 +59,7 @@ into_diagnostic_arg_using_display!(
     i128,
     u128,
     std::io::Error,
-    std::boxed::Box<dyn std::error::Error>,
+    Box<dyn std::error::Error>,
     std::num::NonZeroU32,
     hir::Target,
     Edition,
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index 9d6a4f9a1fd..321c43a1aba 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -26,7 +26,6 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, FileName, RealFileName, Span, DUMMY_SP};
 use smallvec::{smallvec, SmallVec};
 
-use std::default::Default;
 use std::iter;
 use std::path::PathBuf;
 use std::rc::Rc;
diff --git a/compiler/rustc_hir/src/pat_util.rs b/compiler/rustc_hir/src/pat_util.rs
index 6e2fbf96cbf..e870aa543d0 100644
--- a/compiler/rustc_hir/src/pat_util.rs
+++ b/compiler/rustc_hir/src/pat_util.rs
@@ -6,7 +6,7 @@ use rustc_span::hygiene::DesugaringKind;
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 
-use std::iter::{Enumerate, ExactSizeIterator};
+use std::iter::Enumerate;
 
 pub struct EnumerateAndAdjust<I> {
     enumerate: Enumerate<I>,
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index b065ace6bf5..69eb96fe8e9 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -31,7 +31,6 @@ use rustc_trait_selection::traits::{
 };
 
 use std::cell::LazyCell;
-use std::convert::TryInto;
 use std::iter;
 use std::ops::{ControlFlow, Deref};
 
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index a8acaf6597a..d1d328128bc 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -30,8 +30,6 @@ use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
-use std::iter::FromIterator;
-use std::vec::Vec;
 
 const LOADED_FROM_DISK: Symbol = sym::loaded_from_disk;
 const EXCEPT: Symbol = sym::except;
diff --git a/compiler/rustc_incremental/src/persist/fs.rs b/compiler/rustc_incremental/src/persist/fs.rs
index 97ebed05855..1fd2b9b0d7b 100644
--- a/compiler/rustc_incremental/src/persist/fs.rs
+++ b/compiler/rustc_incremental/src/persist/fs.rs
@@ -113,7 +113,6 @@ use rustc_span::Symbol;
 
 use std::fs as std_fs;
 use std::io::{self, ErrorKind};
-use std::mem;
 use std::path::{Path, PathBuf};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
@@ -305,7 +304,7 @@ pub fn prepare_session_directory(
             }
 
             delete_session_dir_lock_file(sess, &lock_file_path);
-            mem::drop(directory_lock);
+            drop(directory_lock);
         }
     }
 }
@@ -864,7 +863,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
 
                     // Let's make it explicit that the file lock is released at this point,
                     // or rather, that we held on to it until here
-                    mem::drop(lock);
+                    drop(lock);
                 }
                 Err(_) => {
                     debug!(
@@ -898,7 +897,7 @@ pub fn garbage_collect_session_directories(sess: &Session) -> io::Result<()> {
 
         // Let's make it explicit that the file lock is released at this point,
         // or rather, that we held on to it until here
-        mem::drop(lock);
+        drop(lock);
     }
 
     Ok(())
diff --git a/compiler/rustc_index/src/vec.rs b/compiler/rustc_index/src/vec.rs
index 39aa27a23c1..c18a911b2fb 100644
--- a/compiler/rustc_index/src/vec.rs
+++ b/compiler/rustc_index/src/vec.rs
@@ -4,7 +4,6 @@ use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use std::fmt;
 use std::fmt::Debug;
 use std::hash::Hash;
-use std::iter::FromIterator;
 use std::marker::PhantomData;
 use std::ops::{Index, IndexMut, RangeBounds};
 use std::slice;
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 2b8f6557c82..e903cb86dd2 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -25,7 +25,6 @@ use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrate
 use rustc_target::spec::{RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel};
 
 use std::collections::{BTreeMap, BTreeSet};
-use std::iter::FromIterator;
 use std::num::NonZeroUsize;
 use std::path::{Path, PathBuf};
 
diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index 3fbabbc6344..50d6d5b9bab 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -34,7 +34,6 @@ pub use crate::cursor::Cursor;
 use self::LiteralKind::*;
 use self::TokenKind::*;
 use crate::cursor::EOF_CHAR;
-use std::convert::TryFrom;
 
 /// Parsed token.
 /// It doesn't contain information about data that has been parsed,
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index 297b509d402..8446da6098e 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -16,7 +16,6 @@ use rustc_target::abi::{Abi, Size, WrappingRange};
 use rustc_target::abi::{Integer, TagEncoding, Variants};
 use rustc_target::spec::abi::Abi as SpecAbi;
 
-use std::cmp;
 use std::iter;
 use std::ops::ControlFlow;
 
@@ -531,7 +530,7 @@ impl<'tcx> LateLintPass<'tcx> for TypeLimits {
             _ => {}
         };
 
-        fn is_valid<T: cmp::PartialOrd>(binop: hir::BinOp, v: T, min: T, max: T) -> bool {
+        fn is_valid<T: PartialOrd>(binop: hir::BinOp, v: T, min: T, max: T) -> bool {
             match binop.node {
                 hir::BinOpKind::Lt => v > min && v <= max,
                 hir::BinOpKind::Le => v >= min && v < max,
diff --git a/compiler/rustc_metadata/src/rmeta/table.rs b/compiler/rustc_metadata/src/rmeta/table.rs
index 29fe6110797..716655c7f14 100644
--- a/compiler/rustc_metadata/src/rmeta/table.rs
+++ b/compiler/rustc_metadata/src/rmeta/table.rs
@@ -7,7 +7,6 @@ use rustc_middle::ty::ParameterizedOverTcx;
 use rustc_serialize::opaque::FileEncoder;
 use rustc_serialize::Encoder as _;
 use rustc_span::hygiene::MacroKind;
-use std::convert::TryInto;
 use std::marker::PhantomData;
 use std::num::NonZeroUsize;
 
diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs
index efa9464529e..0b55757eb03 100644
--- a/compiler/rustc_middle/src/mir/coverage.rs
+++ b/compiler/rustc_middle/src/mir/coverage.rs
@@ -3,7 +3,6 @@
 use rustc_macros::HashStable;
 use rustc_span::Symbol;
 
-use std::cmp::Ord;
 use std::fmt::{self, Debug, Formatter};
 
 rustc_index::newtype_index! {
diff --git a/compiler/rustc_middle/src/mir/interpret/mod.rs b/compiler/rustc_middle/src/mir/interpret/mod.rs
index d79cd8b7a8a..8fe349d9640 100644
--- a/compiler/rustc_middle/src/mir/interpret/mod.rs
+++ b/compiler/rustc_middle/src/mir/interpret/mod.rs
@@ -95,7 +95,6 @@ mod pointer;
 mod queries;
 mod value;
 
-use std::convert::TryFrom;
 use std::fmt;
 use std::io;
 use std::io::{Read, Write};
diff --git a/compiler/rustc_middle/src/mir/interpret/pointer.rs b/compiler/rustc_middle/src/mir/interpret/pointer.rs
index 9c270ba1ec1..b0830991076 100644
--- a/compiler/rustc_middle/src/mir/interpret/pointer.rs
+++ b/compiler/rustc_middle/src/mir/interpret/pointer.rs
@@ -3,7 +3,6 @@ use super::{AllocId, InterpResult};
 use rustc_macros::HashStable;
 use rustc_target::abi::{HasDataLayout, Size};
 
-use std::convert::{TryFrom, TryInto};
 use std::fmt;
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/compiler/rustc_middle/src/mir/interpret/value.rs b/compiler/rustc_middle/src/mir/interpret/value.rs
index e6636e50e6e..88fb14eb359 100644
--- a/compiler/rustc_middle/src/mir/interpret/value.rs
+++ b/compiler/rustc_middle/src/mir/interpret/value.rs
@@ -1,4 +1,3 @@
-use std::convert::{TryFrom, TryInto};
 use std::fmt;
 
 use either::{Either, Left, Right};
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index a513444e1e0..db4fe6f886b 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -36,7 +36,6 @@ use rustc_span::{Span, DUMMY_SP};
 use either::Either;
 
 use std::borrow::Cow;
-use std::convert::TryInto;
 use std::fmt::{self, Debug, Display, Formatter, Write};
 use std::ops::{ControlFlow, Index, IndexMut};
 use std::{iter, mem};
diff --git a/compiler/rustc_middle/src/traits/query.rs b/compiler/rustc_middle/src/traits/query.rs
index fb152b63f63..d40d7de5f31 100644
--- a/compiler/rustc_middle/src/traits/query.rs
+++ b/compiler/rustc_middle/src/traits/query.rs
@@ -12,7 +12,6 @@ use crate::ty::subst::{GenericArg, SubstsRef};
 use crate::ty::{self, Ty, TyCtxt};
 use rustc_hir::def_id::DefId;
 use rustc_span::source_map::Span;
-use std::iter::FromIterator;
 
 pub mod type_op {
     use crate::ty::fold::TypeFoldable;
diff --git a/compiler/rustc_middle/src/ty/consts/int.rs b/compiler/rustc_middle/src/ty/consts/int.rs
index f3186e1c30c..2a8a4d59888 100644
--- a/compiler/rustc_middle/src/ty/consts/int.rs
+++ b/compiler/rustc_middle/src/ty/consts/int.rs
@@ -2,7 +2,6 @@ use rustc_apfloat::ieee::{Double, Single};
 use rustc_apfloat::Float;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 use rustc_target::abi::Size;
-use std::convert::{TryFrom, TryInto};
 use std::fmt;
 use std::num::NonZeroU8;
 
diff --git a/compiler/rustc_middle/src/ty/consts/kind.rs b/compiler/rustc_middle/src/ty/consts/kind.rs
index becc2b805dd..d9721863a58 100644
--- a/compiler/rustc_middle/src/ty/consts/kind.rs
+++ b/compiler/rustc_middle/src/ty/consts/kind.rs
@@ -1,5 +1,3 @@
-use std::convert::TryInto;
-
 use super::Const;
 use crate::mir;
 use crate::mir::interpret::{AllocId, ConstValue, Scalar};
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 5303341ba44..01e96fa5c7a 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -23,7 +23,6 @@ use smallvec::SmallVec;
 use std::cell::Cell;
 use std::char;
 use std::collections::BTreeMap;
-use std::convert::TryFrom;
 use std::fmt::{self, Write as _};
 use std::iter;
 use std::ops::{ControlFlow, Deref, DerefMut};
diff --git a/compiler/rustc_middle/src/ty/vtable.rs b/compiler/rustc_middle/src/ty/vtable.rs
index 6eae94511e4..802925dfb04 100644
--- a/compiler/rustc_middle/src/ty/vtable.rs
+++ b/compiler/rustc_middle/src/ty/vtable.rs
@@ -1,4 +1,3 @@
-use std::convert::TryFrom;
 use std::fmt;
 
 use crate::mir::interpret::{alloc_range, AllocId, Allocation, Pointer, Scalar};
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index 691cbee2c73..ba6bc41c667 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -30,7 +30,6 @@ mod test;
 mod util;
 
 use std::borrow::Borrow;
-use std::convert::TryFrom;
 use std::mem;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
diff --git a/compiler/rustc_mir_build/src/build/matches/util.rs b/compiler/rustc_mir_build/src/build/matches/util.rs
index bd435f9ab00..cbd494862a0 100644
--- a/compiler/rustc_mir_build/src/build/matches/util.rs
+++ b/compiler/rustc_mir_build/src/build/matches/util.rs
@@ -7,7 +7,6 @@ use rustc_middle::thir::*;
 use rustc_middle::ty;
 use rustc_middle::ty::TypeVisitable;
 use smallvec::SmallVec;
-use std::convert::TryInto;
 
 impl<'a, 'tcx> Builder<'a, 'tcx> {
     pub(crate) fn field_match_pairs<'pat>(
diff --git a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
index d60e8722cb6..18e9c69c487 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
@@ -45,7 +45,7 @@
 use std::cell::Cell;
 use std::cmp::{self, max, min, Ordering};
 use std::fmt;
-use std::iter::{once, IntoIterator};
+use std::iter::once;
 use std::ops::RangeInclusive;
 
 use smallvec::{smallvec, SmallVec};
diff --git a/compiler/rustc_mir_dataflow/src/framework/lattice.rs b/compiler/rustc_mir_dataflow/src/framework/lattice.rs
index f0e75c53ea1..8fdac7b2cf5 100644
--- a/compiler/rustc_mir_dataflow/src/framework/lattice.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/lattice.rs
@@ -26,7 +26,7 @@
 //! ## `PartialOrd`
 //!
 //! Given that they represent partially ordered sets, you may be surprised that [`JoinSemiLattice`]
-//! and [`MeetSemiLattice`] do not have [`PartialOrd`][std::cmp::PartialOrd] as a supertrait. This
+//! and [`MeetSemiLattice`] do not have [`PartialOrd`] as a supertrait. This
 //! is because most standard library types use lexicographic ordering instead of set inclusion for
 //! their `PartialOrd` impl. Since we do not actually need to compare lattice elements to run a
 //! dataflow analysis, there's no need for a newtype wrapper with a custom `PartialOrd` impl. The
diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index 475e2ec9a1d..8212a7b523b 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -35,7 +35,6 @@ use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Vis
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
 use smallvec::SmallVec;
-use std::convert::TryInto;
 
 pub struct SimplifyCfg {
     label: String,
diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs
index 650076c2213..703ed09a254 100644
--- a/compiler/rustc_monomorphize/src/polymorphize.rs
+++ b/compiler/rustc_monomorphize/src/polymorphize.rs
@@ -20,7 +20,6 @@ use rustc_middle::ty::{
     Const, Ty, TyCtxt,
 };
 use rustc_span::symbol::sym;
-use std::convert::TryInto;
 use std::ops::ControlFlow;
 
 use crate::errors::UnusedGenericParams;
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index c7d239b647f..686454a8f18 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -6,7 +6,6 @@ use rustc_ast::attr;
 use rustc_ast::token::{self, Delimiter, Nonterminal};
 use rustc_errors::{error_code, fluent, Diagnostic, IntoDiagnostic, PResult};
 use rustc_span::{sym, BytePos, Span};
-use std::convert::TryInto;
 
 // Public for rustfmt usage
 #[derive(Debug)]
diff --git a/compiler/rustc_parse/src/parser/attr_wrapper.rs b/compiler/rustc_parse/src/parser/attr_wrapper.rs
index a084a701088..b97f22417cb 100644
--- a/compiler/rustc_parse/src/parser/attr_wrapper.rs
+++ b/compiler/rustc_parse/src/parser/attr_wrapper.rs
@@ -8,7 +8,6 @@ use rustc_errors::PResult;
 use rustc_session::parse::ParseSess;
 use rustc_span::{sym, Span, DUMMY_SP};
 
-use std::convert::TryInto;
 use std::ops::Range;
 
 /// A wrapper type to ensure that the parser handles outer attributes correctly.
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 03f25392a7c..7ebcda249e2 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -21,7 +21,6 @@ use rustc_span::lev_distance::lev_distance;
 use rustc_span::source_map::{self, Span};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::DUMMY_SP;
-use std::convert::TryFrom;
 use std::mem;
 use thin_vec::ThinVec;
 use tracing::debug;
diff --git a/compiler/rustc_query_system/src/dep_graph/graph.rs b/compiler/rustc_query_system/src/dep_graph/graph.rs
index 38c7c6cce67..0e7d628c1eb 100644
--- a/compiler/rustc_query_system/src/dep_graph/graph.rs
+++ b/compiler/rustc_query_system/src/dep_graph/graph.rs
@@ -46,7 +46,7 @@ impl DepNodeIndex {
     pub const FOREVER_RED_NODE: DepNodeIndex = DepNodeIndex::from_u32(1);
 }
 
-impl std::convert::From<DepNodeIndex> for QueryInvocationId {
+impl From<DepNodeIndex> for QueryInvocationId {
     #[inline]
     fn from(dep_node_index: DepNodeIndex) -> Self {
         QueryInvocationId(dep_node_index.as_u32())
diff --git a/compiler/rustc_query_system/src/dep_graph/serialized.rs b/compiler/rustc_query_system/src/dep_graph/serialized.rs
index 3b20ec70d73..d292f4beef2 100644
--- a/compiler/rustc_query_system/src/dep_graph/serialized.rs
+++ b/compiler/rustc_query_system/src/dep_graph/serialized.rs
@@ -22,7 +22,6 @@ use rustc_index::vec::{Idx, IndexVec};
 use rustc_serialize::opaque::{FileEncodeResult, FileEncoder, IntEncodedWithFixedSize, MemDecoder};
 use rustc_serialize::{Decodable, Decoder, Encodable};
 use smallvec::SmallVec;
-use std::convert::TryInto;
 
 // The maximum value of `SerializedDepNodeIndex` leaves the upper two bits
 // unused so that we can store multiple index types in `CompressedHybridIndex`,
diff --git a/compiler/rustc_query_system/src/query/caches.rs b/compiler/rustc_query_system/src/query/caches.rs
index 4c4680b5d8e..f65846fc77f 100644
--- a/compiler/rustc_query_system/src/query/caches.rs
+++ b/compiler/rustc_query_system/src/query/caches.rs
@@ -9,7 +9,6 @@ use rustc_data_structures::sharded::Sharded;
 use rustc_data_structures::sync::Lock;
 use rustc_data_structures::sync::WorkerLocal;
 use rustc_index::vec::{Idx, IndexVec};
-use std::default::Default;
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::marker::PhantomData;
diff --git a/compiler/rustc_query_system/src/query/job.rs b/compiler/rustc_query_system/src/query/job.rs
index 49bbcf57804..701bbde6ad2 100644
--- a/compiler/rustc_query_system/src/query/job.rs
+++ b/compiler/rustc_query_system/src/query/job.rs
@@ -22,8 +22,8 @@ use {
     rustc_data_structures::{jobserver, OnDrop},
     rustc_rayon_core as rayon_core,
     rustc_span::DUMMY_SP,
-    std::iter::{self, FromIterator},
-    std::{mem, process},
+    std::iter,
+    std::process,
 };
 
 /// Represents a span and a query key.
@@ -247,7 +247,7 @@ impl QueryLatch {
             jobserver::release_thread();
             waiter.condvar.wait(&mut info);
             // Release the lock before we potentially block in `acquire_thread`
-            mem::drop(info);
+            drop(info);
             jobserver::acquire_thread();
         }
     }
diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
index 7735c571310..6c310abf10a 100644
--- a/compiler/rustc_save_analysis/src/lib.rs
+++ b/compiler/rustc_save_analysis/src/lib.rs
@@ -36,7 +36,6 @@ use rustc_span::symbol::Ident;
 use rustc_span::*;
 
 use std::cell::Cell;
-use std::default::Default;
 use std::env;
 use std::fs::File;
 use std::io::BufWriter;
diff --git a/compiler/rustc_serialize/src/opaque.rs b/compiler/rustc_serialize/src/opaque.rs
index 0afeb86fceb..0e0ebc79eb2 100644
--- a/compiler/rustc_serialize/src/opaque.rs
+++ b/compiler/rustc_serialize/src/opaque.rs
@@ -1,6 +1,5 @@
 use crate::leb128::{self, largest_max_leb128_len};
 use crate::serialize::{Decodable, Decoder, Encodable, Encoder};
-use std::convert::TryInto;
 use std::fs::File;
 use std::io::{self, Write};
 use std::mem::MaybeUninit;
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 7a20100fd31..6de564a3a06 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -32,7 +32,7 @@ use std::collections::btree_map::{
 use std::collections::{BTreeMap, BTreeSet};
 use std::fmt;
 use std::hash::Hash;
-use std::iter::{self, FromIterator};
+use std::iter;
 use std::path::{Path, PathBuf};
 use std::str::{self, FromStr};
 
diff --git a/compiler/rustc_session/src/filesearch.rs b/compiler/rustc_session/src/filesearch.rs
index 1b66773be6f..1855a49c1ec 100644
--- a/compiler/rustc_session/src/filesearch.rs
+++ b/compiler/rustc_session/src/filesearch.rs
@@ -3,7 +3,6 @@
 use smallvec::{smallvec, SmallVec};
 use std::env;
 use std::fs;
-use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 
 use crate::search_paths::{PathKind, SearchPath};
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index 2ae57d9e56d..43a31722707 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -15,11 +15,10 @@ pub use crate::*;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_data_structures::sync::{AtomicU32, Lrc, MappedReadGuard, ReadGuard, RwLock};
+use std::cmp;
 use std::hash::Hash;
 use std::path::{Path, PathBuf};
 use std::sync::atomic::Ordering;
-use std::{clone::Clone, cmp};
-use std::{convert::TryFrom, unreachable};
 
 use std::fs;
 use std::io;
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 1fcf8c7a8bf..d0fe598ce08 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -9,7 +9,6 @@ use rustc_data_structures::sync::Lock;
 use rustc_macros::HashStable_Generic;
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
-use std::cmp::{Ord, PartialEq, PartialOrd};
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::str;
@@ -1974,7 +1973,6 @@ pub mod kw {
 /// For example `sym::rustfmt` or `sym::u8`.
 pub mod sym {
     use super::Symbol;
-    use std::convert::TryInto;
 
     #[doc(inline)]
     pub use super::sym_generated::*;
diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index b69a0a645a4..dc2cc23ffb1 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -18,7 +18,6 @@
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
-use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 
 #[macro_use]
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 1db1d7e85ad..be994eda14c 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -45,9 +45,7 @@ use rustc_span::symbol::{sym, Symbol};
 use serde_json::Value;
 use std::borrow::Cow;
 use std::collections::BTreeMap;
-use std::convert::TryFrom;
 use std::hash::{Hash, Hasher};
-use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
diff --git a/compiler/rustc_type_ir/src/sty.rs b/compiler/rustc_type_ir/src/sty.rs
index 3ed616d709b..9aa2be124e2 100644
--- a/compiler/rustc_type_ir/src/sty.rs
+++ b/compiler/rustc_type_ir/src/sty.rs
@@ -1,6 +1,6 @@
 #![allow(rustc::usage_of_ty_tykind)]
 
-use std::cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd};
+use std::cmp::Ordering;
 use std::{fmt, hash};
 
 use crate::DebruijnIndex;
-- 
cgit 1.4.1-3-g733a5