Rollup merge of #76567 - matthiaskrgr:clone_on_copy, r=varkor

tmandry · web-flow · commit c8f9c728c292 · 2020-09-10T12:20:12.000-07:00
use push(char) to add chars (single-char &amp;strs) to strings instead of push_str(&amp;str)
diff --git a/compiler/rustc_builtin_macros/src/format_foreign.rs b/compiler/rustc_builtin_macros/src/format_foreign.rs
@@ -166,14 +166,14 @@ pub mod printf {
             let cap = self.span.len() + if has_options { 2 } else { 0 };
             let mut s = String::with_capacity(cap);
 
-            s.push_str("{");
+            s.push('{');
 
             if let Some(arg) = self.parameter {
                 write!(s, "{}", arg.checked_sub(1)?).ok()?;
             }
 
             if has_options {
-                s.push_str(":");
+                s.push(':');
 
                 let align = if let Some(fill) = fill {
                     s.push_str(fill);
@@ -191,19 +191,19 @@ pub mod printf {
                 }
 
                 if alt {
-                    s.push_str("#");
+                    s.push('#');
                 }
 
                 if zero_fill {
-                    s.push_str("0");
+                    s.push('0');
                 }
 
                 if let Some(width) = width {
                     width.translate(&mut s).ok()?;
                 }
 
                 if let Some(precision) = precision {
-                    s.push_str(".");
+                    s.push('.');
                     precision.translate(&mut s).ok()?;
                 }
 
@@ -212,7 +212,7 @@ pub mod printf {
                 }
             }
 
-            s.push_str("}");
+            s.push('}');
             Some(s)
         }
     }
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -1076,7 +1076,7 @@ fn exec_linker(
             }
             .to_string(),
         );
-        args.push_str("\n");
+        args.push('\n');
     }
     let file = tmpdir.join("linker-arguments");
     let bytes = if sess.target.target.options.is_like_msvc {
diff --git a/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs b/compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
@@ -37,7 +37,7 @@ pub fn push_debuginfo_type_name<'tcx>(
         ty::Bool => output.push_str("bool"),
         ty::Char => output.push_str("char"),
         ty::Str => output.push_str("str"),
-        ty::Never => output.push_str("!"),
+        ty::Never => output.push('!'),
         ty::Int(int_ty) => output.push_str(int_ty.name_str()),
         ty::Uint(uint_ty) => output.push_str(uint_ty.name_str()),
         ty::Float(float_ty) => output.push_str(float_ty.name_str()),
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -2093,7 +2093,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 _ => String::new(),
             };
             if !s.is_empty() {
-                s.push_str(" ");
+                s.push(' ');
             }
             s
         };
diff --git a/compiler/rustc_infer/src/infer/lub.rs b/compiler/rustc_infer/src/infer/lub.rs
@@ -50,7 +50,7 @@ impl TypeRelation<'tcx> for Lub<'combine, 'infcx, 'tcx> {
             ty::Invariant => self.fields.equate(self.a_is_expected).relate(a, b),
             ty::Covariant => self.relate(a, b),
             // FIXME(#41044) -- not correct, need test
-            ty::Bivariant => Ok(a.clone()),
+            ty::Bivariant => Ok(a),
             ty::Contravariant => self.fields.glb(self.a_is_expected).relate(a, b),
         }
     }
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
@@ -150,8 +150,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             Some(mut descr) => {
                 // Surround descr with `backticks`.
                 descr.reserve(2);
-                descr.insert_str(0, "`");
-                descr.push_str("`");
+                descr.insert(0, '`');
+                descr.push('`');
                 descr
             }
             None => "value".to_string(),
@@ -222,7 +222,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             if self.upvars[var_index].by_ref {
                                 buf.push_str(&name);
                             } else {
-                                buf.push_str(&format!("*{}", &name));
+                                buf.push('*');
+                                buf.push_str(&name);
                             }
                         } else {
                             if autoderef {
@@ -234,7 +235,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                     &including_downcast,
                                 )?;
                             } else {
-                                buf.push_str(&"*");
+                                buf.push('*');
                                 self.append_place_to_string(
                                     PlaceRef { local, projection: proj_base },
                                     buf,
@@ -272,7 +273,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 autoderef,
                                 &including_downcast,
                             )?;
-                            buf.push_str(&format!(".{}", field_name));
+                            buf.push('.');
+                            buf.push_str(&field_name);
                         }
                     }
                     ProjectionElem::Index(index) => {
@@ -284,11 +286,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             autoderef,
                             &including_downcast,
                         )?;
-                        buf.push_str("[");
+                        buf.push('[');
                         if self.append_local_to_string(*index, buf).is_err() {
-                            buf.push_str("_");
+                            buf.push('_');
                         }
-                        buf.push_str("]");
+                        buf.push(']');
                     }
                     ProjectionElem::ConstantIndex { .. } | ProjectionElem::Subslice { .. } => {
                         autoderef = true;
@@ -301,7 +303,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             autoderef,
                             &including_downcast,
                         )?;
-                        buf.push_str(&"[..]");
+                        buf.push_str("[..]");
                     }
                 };
             }
@@ -648,7 +650,7 @@ impl UseSpans {
                     " in closure".to_string()
                 }
             }
-            _ => "".to_string(),
+            _ => String::new(),
         }
     }
 
diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/values.rs b/compiler/rustc_mir/src/borrow_check/region_infer/values.rs
@@ -417,7 +417,7 @@ crate fn location_set_str(
 
 fn region_value_str(elements: impl IntoIterator<Item = RegionElement>) -> String {
     let mut result = String::new();
-    result.push_str("{");
+    result.push('{');
 
     // Set to Some(l1, l2) when we have observed all the locations
     // from l1..=l2 (inclusive) but not yet printed them. This
@@ -478,7 +478,7 @@ fn region_value_str(elements: impl IntoIterator<Item = RegionElement>) -> String
         push_location_range(&mut result, location1, location2);
     }
 
-    result.push_str("}");
+    result.push('}');
 
     return result;
 
diff --git a/compiler/rustc_mir/src/monomorphize/partitioning/mod.rs b/compiler/rustc_mir/src/monomorphize/partitioning/mod.rs
@@ -382,7 +382,7 @@ fn collect_and_partition_mono_items<'tcx>(
                 cgus.sort_by_key(|(name, _)| *name);
                 cgus.dedup();
                 for &(ref cgu_name, (linkage, _)) in cgus.iter() {
-                    output.push_str(" ");
+                    output.push(' ');
                     output.push_str(&cgu_name.as_str());
 
                     let linkage_abbrev = match linkage {
@@ -399,9 +399,9 @@ fn collect_and_partition_mono_items<'tcx>(
                         Linkage::Common => "Common",
                     };
 
-                    output.push_str("[");
+                    output.push('[');
                     output.push_str(linkage_abbrev);
-                    output.push_str("]");
+                    output.push(']');
                 }
                 output
             })
diff --git a/compiler/rustc_mir/src/transform/instrument_coverage.rs b/compiler/rustc_mir/src/transform/instrument_coverage.rs
@@ -353,7 +353,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {
                             if !INCLUDE_COVERAGE_STATEMENTS {
                                 continue;
                             }
-                            format!("unreachable")
+                            String::from("unreachable")
                         }
                     },
                     _ => format!("{:?}", statement),
diff --git a/compiler/rustc_mir/src/util/pretty.rs b/compiler/rustc_mir/src/util/pretty.rs
@@ -514,7 +514,7 @@ fn write_scope_tree(
                 write!(indented_decl, " as {:?}", user_ty).unwrap();
             }
         }
-        indented_decl.push_str(";");
+        indented_decl.push(';');
 
         let local_name =
             if local == RETURN_PLACE { " return place".to_string() } else { String::new() };
diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
@@ -438,7 +438,7 @@ impl<'tcx> SaveContext<'tcx> {
                                     .next()
                                     .map(|item| item.def_id);
                             }
-                            qualname.push_str(">");
+                            qualname.push('>');
 
                             (qualname, trait_id, decl_id, docs, attrs)
                         }
diff --git a/compiler/rustc_save_analysis/src/sig.rs b/compiler/rustc_save_analysis/src/sig.rs
@@ -497,7 +497,7 @@ impl<'hir> Sig for hir::Item<'hir> {
                     sig.text.push_str(&bounds_to_string(bounds));
                 }
                 // FIXME where clause
-                sig.text.push_str(";");
+                sig.text.push(';');
 
                 Ok(sig)
             }
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
@@ -581,9 +581,9 @@ impl OutputFilenames {
 
         if !ext.is_empty() {
             if !extension.is_empty() {
-                extension.push_str(".");
+                extension.push('.');
                 extension.push_str(RUST_CGU_EXT);
-                extension.push_str(".");
+                extension.push('.');
             }
 
             extension.push_str(ext);

Original file line number	Diff line number	Diff line change
`@@ -166,14 +166,14 @@ pub mod printf {`
`166`	`166`	`let cap = self.span.len() + if has_options { 2 } else { 0 };`
`167`	`167`	`let mut s = String::with_capacity(cap);`
`168`	`168`
`169`		`- s.push_str("{");`
	`169`	`+ s.push('{');`
`170`	`170`
`171`	`171`	`if let Some(arg) = self.parameter {`
`172`	`172`	`write!(s, "{}", arg.checked_sub(1)?).ok()?;`
`173`	`173`	`}`
`174`	`174`
`175`	`175`	`if has_options {`
`176`		`- s.push_str(":");`
	`176`	`+ s.push(':');`
`177`	`177`
`178`	`178`	`let align = if let Some(fill) = fill {`
`179`	`179`	`s.push_str(fill);`
`@@ -191,19 +191,19 @@ pub mod printf {`
`191`	`191`	`}`
`192`	`192`
`193`	`193`	`if alt {`
`194`		`- s.push_str("#");`
	`194`	`+ s.push('#');`
`195`	`195`	`}`
`196`	`196`
`197`	`197`	`if zero_fill {`
`198`		`- s.push_str("0");`
	`198`	`+ s.push('0');`
`199`	`199`	`}`
`200`	`200`
`201`	`201`	`if let Some(width) = width {`
`202`	`202`	`width.translate(&mut s).ok()?;`
`203`	`203`	`}`
`204`	`204`
`205`	`205`	`if let Some(precision) = precision {`
`206`		`- s.push_str(".");`
	`206`	`+ s.push('.');`
`207`	`207`	`precision.translate(&mut s).ok()?;`
`208`	`208`	`}`
`209`	`209`
`@@ -212,7 +212,7 @@ pub mod printf {`
`212`	`212`	`}`
`213`	`213`	`}`
`214`	`214`
`215`		`- s.push_str("}");`
	`215`	`+ s.push('}');`
`216`	`216`	`Some(s)`
`217`	`217`	`}`
`218`	`218`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1076,7 +1076,7 @@ fn exec_linker(`
`1076`	`1076`	`}`
`1077`	`1077`	`.to_string(),`
`1078`	`1078`	`);`
`1079`		`- args.push_str("\n");`
	`1079`	`+ args.push('\n');`
`1080`	`1080`	`}`
`1081`	`1081`	`let file = tmpdir.join("linker-arguments");`
`1082`	`1082`	`let bytes = if sess.target.target.options.is_like_msvc {`
Original file line number	Diff line number	Diff line change
`@@ -2093,7 +2093,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {`
`2093`	`2093`	`_ => String::new(),`
`2094`	`2094`	`};`
`2095`	`2095`	`if !s.is_empty() {`
`2096`		`- s.push_str(" ");`
	`2096`	`+ s.push(' ');`
`2097`	`2097`	`}`
`2098`	`2098`	`s`
`2099`	`2099`	`};`
Original file line number	Diff line number	Diff line change
`@@ -50,7 +50,7 @@ impl TypeRelation<'tcx> for Lub<'combine, 'infcx, 'tcx> {`
`50`	`50`	`ty::Invariant => self.fields.equate(self.a_is_expected).relate(a, b),`
`51`	`51`	`ty::Covariant => self.relate(a, b),`
`52`	`52`	`// FIXME(#41044) -- not correct, need test`
`53`		`- ty::Bivariant => Ok(a.clone()),`
	`53`	`+ ty::Bivariant => Ok(a),`
`54`	`54`	`ty::Contravariant => self.fields.glb(self.a_is_expected).relate(a, b),`
`55`	`55`	`}`
`56`	`56`	`}`
Original file line number	Diff line number	Diff line change
`@@ -353,7 +353,7 @@ impl<'a, 'tcx> Instrumentor<'a, 'tcx> {`
`353`	`353`	`if !INCLUDE_COVERAGE_STATEMENTS {`
`354`	`354`	`continue;`
`355`	`355`	`}`
`356`		`- format!("unreachable")`
	`356`	`+ String::from("unreachable")`
`357`	`357`	`}`
`358`	`358`	`},`
`359`	`359`	`_ => format!("{:?}", statement),`
Original file line number	Diff line number	Diff line change
`@@ -514,7 +514,7 @@ fn write_scope_tree(`
`514`	`514`	`write!(indented_decl, " as {:?}", user_ty).unwrap();`
`515`	`515`	`}`
`516`	`516`	`}`
`517`		`- indented_decl.push_str(";");`
	`517`	`+ indented_decl.push(';');`
`518`	`518`
`519`	`519`	`let local_name =`
`520`	`520`	`if local == RETURN_PLACE { " return place".to_string() } else { String::new() };`