diff --git a/src/librustc/infer/opaque_types/mod.rs b/src/librustc/infer/opaque_types/mod.rs
index 8e9af8b39385f..1c52b5775a0cc 100644
--- a/src/librustc/infer/opaque_types/mod.rs
+++ b/src/librustc/infer/opaque_types/mod.rs
@@ -307,7 +307,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
let required_region_bounds = tcx.required_region_bounds(
opaque_type,
- bounds.predicates.clone(),
+ bounds.predicates,
);
debug_assert!(!required_region_bounds.is_empty());
diff --git a/src/librustc/middle/liveness.rs b/src/librustc/middle/liveness.rs
index 260935a38d6d4..29c624575c3c2 100644
--- a/src/librustc/middle/liveness.rs
+++ b/src/librustc/middle/liveness.rs
@@ -1617,7 +1617,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
self.ir.tcx.lint_hir_note(
lint::builtin::UNUSED_VARIABLES,
hir_id,
- spans.clone(),
+ spans,
&format!("variable `{}` is assigned to, but never used", name),
&format!("consider using `_{}` instead", name),
);
diff --git a/src/librustc_borrowck/borrowck/check_loans.rs b/src/librustc_borrowck/borrowck/check_loans.rs
index 4a36d441d3d9f..54989db46c1c5 100644
--- a/src/librustc_borrowck/borrowck/check_loans.rs
+++ b/src/librustc_borrowck/borrowck/check_loans.rs
@@ -36,7 +36,7 @@ fn owned_ptr_base_path<'a, 'tcx>(loan_path: &'a LoanPath<'tcx>) -> &'a LoanPath<
return match helper(loan_path) {
Some(new_loan_path) => new_loan_path,
- None => loan_path.clone()
+ None => loan_path,
};
fn helper<'a, 'tcx>(loan_path: &'a LoanPath<'tcx>) -> Option<&'a LoanPath<'tcx>> {
diff --git a/src/librustc_codegen_llvm/back/lto.rs b/src/librustc_codegen_llvm/back/lto.rs
index 74cda2d2fd182..5d3cc0c0a255f 100644
--- a/src/librustc_codegen_llvm/back/lto.rs
+++ b/src/librustc_codegen_llvm/back/lto.rs
@@ -279,7 +279,7 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
}
}));
serialized_modules.extend(cached_modules.into_iter().map(|(buffer, wp)| {
- (buffer, CString::new(wp.cgu_name.clone()).unwrap())
+ (buffer, CString::new(wp.cgu_name).unwrap())
}));
// For all serialized bitcode files we parse them and link them in as we did
diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index 967fe877fd1ad..588f7481cc060 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -459,7 +459,7 @@ impl CodegenCx<'b, 'tcx> {
};
let f = self.declare_cfn(name, fn_ty);
llvm::SetUnnamedAddr(f, false);
- self.intrinsics.borrow_mut().insert(name, f.clone());
+ self.intrinsics.borrow_mut().insert(name, f);
f
}
diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index d43adc9cb92c5..fbeda43af42b0 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -1609,7 +1609,7 @@ impl<'tcx> VariantInfo<'tcx> {
// with every variant, make each variant name be just the value
// of the discriminant. The struct name for the variant includes
// the actual variant description.
- format!("{}", variant_index.as_usize()).to_string()
+ format!("{}", variant_index.as_usize())
}
}
}
diff --git a/src/librustc_errors/annotate_snippet_emitter_writer.rs b/src/librustc_errors/annotate_snippet_emitter_writer.rs
index 9f9c7588d977b..7ed2fddf72d23 100644
--- a/src/librustc_errors/annotate_snippet_emitter_writer.rs
+++ b/src/librustc_errors/annotate_snippet_emitter_writer.rs
@@ -194,7 +194,7 @@ impl AnnotateSnippetEmitterWriter {
let converter = DiagnosticConverter {
source_map: self.source_map.clone(),
level: level.clone(),
- message: message.clone(),
+ message,
code: code.clone(),
msp: msp.clone(),
children,
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index 7ffba41e2569a..5fef8e53e1d0c 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -236,7 +236,7 @@ impl<'a> CrateLoader<'a> {
let host_lib = host_lib.unwrap();
self.load_derive_macros(
&host_lib.metadata.get_root(),
- host_lib.dylib.clone().map(|p| p.0),
+ host_lib.dylib.map(|p| p.0),
span
)
} else {
diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs
index 4f73c92be504e..f9e503ee69b12 100644
--- a/src/librustc_mir/build/matches/mod.rs
+++ b/src/librustc_mir/build/matches/mod.rs
@@ -1737,7 +1737,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
pat_span,
}))),
};
- let for_arm_body = self.local_decls.push(local.clone());
+ let for_arm_body = self.local_decls.push(local);
let locals = if has_guard.0 {
let ref_for_guard = self.local_decls.push(LocalDecl::<'tcx> {
// This variable isn't mutated but has a name, so has to be
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 77ac2b96160a6..bf64643e5a745 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -922,7 +922,7 @@ fn receiver_is_valid<'fcx, 'tcx>(
};
let obligation = traits::Obligation::new(
- cause.clone(),
+ cause,
fcx.param_env,
trait_ref.to_predicate()
);
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index 985bb02614b61..20a4f86aedb90 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -317,7 +317,7 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
// Ensure that rustdoc works even if rustc is feature-staged
unstable_features: UnstableFeatures::Allow,
actually_rustdoc: true,
- debugging_opts: debugging_options.clone(),
+ debugging_opts: debugging_options,
error_format,
edition,
describe_lints,
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index 5bce5d6ba5de1..baf99bacb8ee6 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -740,7 +740,7 @@ impl Tester for Collector {
debug!("Creating test {}: {}", name, test);
self.tests.push(testing::TestDescAndFn {
desc: testing::TestDesc {
- name: testing::DynTestName(name.clone()),
+ name: testing::DynTestName(name),
ignore: config.ignore,
// compiler failures are test failures
should_panic: testing::ShouldPanic::No,
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 5dbf21867afa6..ae35d98881078 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -23,6 +23,7 @@ use log::debug;
use rustc_data_structures::fx::{FxHashMap};
use std::borrow::Cow;
use std::collections::hash_map::Entry;
+use std::slice;
use rustc_data_structures::sync::Lrc;
use errors::Applicability;
@@ -358,10 +359,10 @@ pub fn compile(
// don't abort iteration early, so that errors for multiple lhses can be reported
for lhs in &lhses {
- valid &= check_lhs_no_empty_seq(sess, &[lhs.clone()]);
+ valid &= check_lhs_no_empty_seq(sess, slice::from_ref(lhs));
valid &= check_lhs_duplicate_matcher_bindings(
sess,
- &[lhs.clone()],
+ slice::from_ref(lhs),
&mut FxHashMap::default(),
def.id
);
diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 85b524786b2f5..f44a6e7efa4f1 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -887,7 +887,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt<'_>,
};
let fmt_str = &*fmt.node.0.as_str(); // for the suggestions below
- let mut parser = parse::Parser::new(fmt_str, str_style, skips.clone(), append_newline);
+ let mut parser = parse::Parser::new(fmt_str, str_style, skips, append_newline);
let mut unverified_pieces = Vec::new();
while let Some(piece) = parser.next() {
diff --git a/src/libsyntax_ext/proc_macro_server.rs b/src/libsyntax_ext/proc_macro_server.rs
index 00a420d3fa899..b5d5a38ce5b38 100644
--- a/src/libsyntax_ext/proc_macro_server.rs
+++ b/src/libsyntax_ext/proc_macro_server.rs
@@ -409,7 +409,7 @@ impl server::TokenStream for Rustc<'_> {
}
fn from_str(&mut self, src: &str) -> Self::TokenStream {
parse::parse_stream_from_source_str(
- FileName::proc_macro_source_code(src.clone()),
+ FileName::proc_macro_source_code(src),
src.to_string(),
self.sess,
Some(self.call_site),