Replaced some unwrap_or and map_or with lazy variants #82456

klensy · 2021-02-23T22:26:55Z

Replaced some unwrap_or and map_or with unwrap_or_else and map_or_else.

rust-highfive · 2021-02-23T22:26:58Z

(rust-highfive has picked a reviewer for you, use r? to override)

klensy · 2021-02-23T23:46:53Z

There's a bug in rust-log-analyzer, it shows:

-            .self_desc
-            .clone()
-            .clone()
-            .map_or_else(|| String::new(), |ty| format!(" for type `{}`", ty))
+        overlap.self_desc.clone().map_or_else(|| String::new(), |ty| format!(" for type `{}`", ty))

but here actually:

-        overlap
-            .self_desc
-            .clone()
-            .map_or_else(|| String::new(), |ty| format!(" for type `{}`", ty))
+        overlap.self_desc.clone().map_or_else(|| String::new(), |ty| format!(" for type `{}`", ty))

estebank

You can always pass any callable to a place that expects a closure, as long as the number of arguments matches. I'm surprised we don't lint about this.

estebank · 2021-02-24T01:24:40Z

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -2372,7 +2372,7 @@ fn compute_type_parameters(cx: &CodegenCx<'ll, 'tcx>, ty: Ty<'tcx>) -> &'ll DIAr
    fn get_parameter_names(cx: &CodegenCx<'_, '_>, generics: &ty::Generics) -> Vec<Symbol> {
        let mut names = generics
            .parent
-            .map_or(vec![], |def_id| get_parameter_names(cx, cx.tcx.generics_of(def_id)));
+            .map_or_else(|| vec![], |def_id| get_parameter_names(cx, cx.tcx.generics_of(def_id)));


Suggested change

.map_or_else(|| vec![], |def_id| get_parameter_names(cx, cx.tcx.generics_of(def_id)));

.map_or_else(Vec::new, |def_id| get_parameter_names(cx, cx.tcx.generics_of(def_id)));

estebank · 2021-02-24T01:24:50Z

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

-                .parent
-                .map_or(vec![], |def_id| get_parameter_names(cx, cx.tcx.generics_of(def_id)));
+            let mut names = generics.parent.map_or_else(
+                || vec![],


Suggested change

|| vec![],

Vec::new,

estebank · 2021-02-24T01:25:08Z

compiler/rustc_codegen_llvm/src/metadata.rs

-            let name = name_buf.map_or(
-                String::new(), // We got a NULL ptr, ignore `name_len`.
+            let name = name_buf.map_or_else(
+                || String::new(), // We got a NULL ptr, ignore `name_len`.


Suggested change

|| String::new(), // We got a NULL ptr, ignore `name_len`.

String::new, // We got a NULL ptr, ignore `name_len`.

estebank · 2021-02-24T01:25:34Z

compiler/rustc_mir/src/const_eval/eval_queries.rs

@@ -50,7 +50,7 @@ fn eval_body_using_ecx<'mir, 'tcx>(

    let name =
        with_no_trimmed_paths(|| ty::tls::with(|tcx| tcx.def_path_str(cid.instance.def_id())));
-    let prom = cid.promoted.map_or(String::new(), |p| format!("::promoted[{:?}]", p));
+    let prom = cid.promoted.map_or_else(|| String::new(), |p| format!("::promoted[{:?}]", p));


Suggested change

let prom = cid.promoted.map_or_else(|| String::new(), |p| format!("::promoted[{:?}]", p));

let prom = cid.promoted.map_or_else(String::new, |p| format!("::promoted[{:?}]", p));

estebank · 2021-02-24T01:25:48Z

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -223,7 +223,7 @@ impl<'a> Parser<'a> {
        fn tokens_to_string(tokens: &[TokenType]) -> String {
            let mut i = tokens.iter();
            // This might be a sign we need a connect method on `Iterator`.
-            let b = i.next().map_or(String::new(), |t| t.to_string());
+            let b = i.next().map_or_else(|| String::new(), |t| t.to_string());


Suggested change

let b = i.next().map_or_else(|| String::new(), |t| t.to_string());

let b = i.next().map_or_else(String::new, |t| t.to_string());

estebank · 2021-02-24T01:26:57Z

compiler/rustc_trait_selection/src/traits/specialize/mod.rs

-                        overlap.self_desc.map_or(String::new(), |ty| format!(" for `{}`", ty))
+                        overlap
+                            .self_desc
+                            .map_or_else(|| String::new(), |ty| format!(" for `{}`", ty))


Suggested change

.map_or_else(|| String::new(), |ty| format!(" for `{}`", ty))

.map_or_else(String::new, |ty| format!(" for `{}`", ty))

estebank · 2021-02-24T01:27:08Z

compiler/rustc_typeck/src/check/method/probe.rs

@@ -1695,7 +1695,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
            } else {
                self.fcx
                    .associated_item(def_id, name, Namespace::ValueNS)
-                    .map_or(Vec::new(), |x| vec![x])
+                    .map_or_else(|| Vec::new(), |x| vec![x])


Suggested change

.map_or_else(|| Vec::new(), |x| vec![x])

.map_or_else(Vec::new, |x| vec![x])

estebank · 2021-02-24T01:27:23Z

compiler/rustc_typeck/src/check/mod.rs

+        tcx.sess
+            .source_map()
+            .span_to_snippet(span)
+            .map_or_else(|_| String::new(), |s| format!(" `{}`", s)),


Suggested change

.map_or_else(|_| String::new(), |s| format!(" `{}`", s)),

.map_or_else(String::new, |s| format!(" `{}`", s)),

as long as the number of arguments matches

You catched me here and with next 2 suggestions )

estebank · 2021-02-24T01:27:34Z

compiler/rustc_typeck/src/check/pat.rs

@@ -879,7 +879,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
            let sm = tcx.sess.source_map();
            let path_str = sm
                .span_to_snippet(sm.span_until_char(pat.span, '('))
-                .map_or(String::new(), |s| format!(" `{}`", s.trim_end()));
+                .map_or_else(|_| String::new(), |s| format!(" `{}`", s.trim_end()));


Suggested change

.map_or_else(|_| String::new(), |s| format!(" `{}`", s.trim_end()));

.map_or_else(String::new, |s| format!(" `{}`", s.trim_end()));

compiler/rustc_typeck/src/collect.rs

estebank · 2021-02-25T17:24:29Z

@bors r+

bors · 2021-02-25T17:24:30Z

📌 Commit 08b1e80 has been approved by estebank

Replaced some unwrap_or and map_or with lazy variants Replaced some `unwrap_or` and `map_or` with `unwrap_or_else` and `map_or_else`.

…laumeGomez Rollup of 8 pull requests Successful merges: - rust-lang#81940 (Stabilize str_split_once) - rust-lang#82165 (Reword labels on E0308 involving async fn return type) - rust-lang#82456 (Replaced some unwrap_or and map_or with lazy variants) - rust-lang#82491 (Consider inexpensive inlining criteria first) - rust-lang#82506 (Properly account for non-shorthand pattern field in unused variable lint) - rust-lang#82535 (Set codegen thread names) - rust-lang#82545 (rustdoc: add optional woff2 versions of FiraSans.) - rust-lang#82549 (Revert "Update normalize.css to 8.0.1") Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

replaced some unwrap_or with unwrap_or_else

5ff1be1

rust-highfive assigned estebank Feb 23, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 23, 2021

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klensy force-pushed the or-else branch from 7bd3004 to c592430 Compare February 23, 2021 23:14

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klensy force-pushed the or-else branch from c592430 to c0c1000 Compare February 23, 2021 23:26

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replaced some map_or with map_or_else

c75c4a5

klensy force-pushed the or-else branch from c0c1000 to c75c4a5 Compare February 23, 2021 23:47

estebank reviewed Feb 24, 2021

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fix review

08b1e80

klensy force-pushed the or-else branch from 176c141 to 08b1e80 Compare February 25, 2021 01:21

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 25, 2021

GuillaumeGomez mentioned this pull request Feb 26, 2021

Rollup of 9 pull requests #82547

Closed

This was referenced Feb 26, 2021

Rollup of 8 pull requests #82550

Closed

Rollup of 8 pull requests #82552

Merged

bors merged commit 039b1b6 into rust-lang:master Feb 26, 2021

rustbot added this to the 1.52.0 milestone Feb 26, 2021

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Replaced some unwrap_or and map_or with lazy variants #82456

Replaced some unwrap_or and map_or with lazy variants #82456

klensy commented Feb 23, 2021

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estebank commented Feb 25, 2021

bors commented Feb 25, 2021

	.map_or_else(\|\| vec![], \|def_id\| get_parameter_names(cx, cx.tcx.generics_of(def_id)));
	.map_or_else(Vec::new, \|def_id\| get_parameter_names(cx, cx.tcx.generics_of(def_id)));

	\|\| String::new(), // We got a NULL ptr, ignore `name_len`.
	String::new, // We got a NULL ptr, ignore `name_len`.

	let prom = cid.promoted.map_or_else(\|\| String::new(), \|p\| format!("::promoted[{:?}]", p));
	let prom = cid.promoted.map_or_else(String::new, \|p\| format!("::promoted[{:?}]", p));

	let b = i.next().map_or_else(\|\| String::new(), \|t\| t.to_string());
	let b = i.next().map_or_else(String::new, \|t\| t.to_string());

	.map_or_else(\|\| String::new(), \|ty\| format!(" for `{}`", ty))
	.map_or_else(String::new, \|ty\| format!(" for `{}`", ty))

	.map_or_else(\|\| Vec::new(), \|x\| vec![x])
	.map_or_else(Vec::new, \|x\| vec![x])

	.map_or_else(\|_\| String::new(), \|s\| format!(" `{}`", s)),
	.map_or_else(String::new, \|s\| format!(" `{}`", s)),

Replaced some unwrap_or and map_or with lazy variants #82456

Replaced some unwrap_or and map_or with lazy variants #82456

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estebank commented Feb 25, 2021

bors commented Feb 25, 2021