Fix clippy things

Copied from 4db48d9f13

compiler/can/src/pattern.rs

@@ -361,7 +361,7 @@ pub fn canonicalize_pattern<'a>(
 
             // If we encountered an erroneous pattern (e.g. one with shadowing),
             // use the resulting RuntimeError. Otherwise, return a successful record destructure.
-            opt_erroneous.unwrap_or_else(|| Pattern::RecordDestructure {
+            opt_erroneous.unwrap_or(Pattern::RecordDestructure {
                 whole_var,
                 ext_var,
                 destructs,

compiler/load/src/docs.rs

@@ -137,7 +137,7 @@ fn comments_or_new_lines_to_docs<'a>(
         match comment_or_new_line {
             DocComment(doc_str) => {
                 docs.push_str(doc_str);
-                docs.push_str("\n");
+                docs.push('\n');
             }
             Newline | LineComment(_) => {}
         }

compiler/mono/src/ir.rs

@@ -1263,7 +1263,7 @@ fn patterns_to_when<'a>(
                 // Even if the body was Ok, replace it with this Err.
                 // If it was already an Err, leave it at that Err, so the first
                 // RuntimeError we encountered remains the first.
-                body = body.and_then(|_| {
+                body = body.and({
                     Err(Located {
                         region: pattern.region,
                         value,

compiler/parse/src/type_annotation.rs

@@ -342,7 +342,7 @@ fn parse_concrete_type<'a>(
         //
         // If we made it this far and don't have a next_char, then necessarily
         // we have consumed a '.' char previously.
-        return malformed(next_char.or_else(|| Some('.')), arena, state, parts);
+        return malformed(next_char.or(Some('.')), arena, state, parts);
     }
 
     if part_buf.is_empty() {

roc_std/src/alloca.rs

@@ -6,7 +6,7 @@ use libc::{c_void, size_t};
 
 #[link(name = "alloca")]
 extern "C" {
-    #[no_mangle]
+    #[allow(dead_code)]
     fn c_alloca(_: size_t) -> *mut c_void;
 }