Auto merge of #55014 - ljedrz:lazyboye_unwraps, r=matthewjasper

Prefer unwrap_or_else to unwrap_or in case of function calls/allocations

The contents of `unwrap_or` are evaluated eagerly, so it's not a good pick in case of function calls and allocations. This PR also changes a few `unwrap_or`s with `unwrap_or_default`.

An added bonus is that in some cases this change also reveals if the object it's called on is an `Option` or a `Result` (based on whether the closure takes an argument).

2 files changed, 2 insertions, 2 deletions

diff --git a/src/librustc_codegen_llvm/llvm/archive_ro.rs b/src/librustc_codegen_llvm/llvm/archive_ro.rs
index e0a9f31e508..2a77f256e3a 100644
--- a/src/librustc_codegen_llvm/llvm/archive_ro.rs
+++ b/src/librustc_codegen_llvm/llvm/archive_ro.rs
@@ -40,7 +40,7 @@ impl ArchiveRO {
         return unsafe {
             let s = path2cstr(dst);
             let ar = super::LLVMRustOpenArchive(s.as_ptr()).ok_or_else(|| {
-                super::last_error().unwrap_or("failed to open archive".to_owned())
+                super::last_error().unwrap_or_else(|| "failed to open archive".to_owned())
             })?;
             Ok(ArchiveRO { raw: ar })
         };
diff --git a/src/librustc_codegen_llvm/llvm/diagnostic.rs b/src/librustc_codegen_llvm/llvm/diagnostic.rs
index c41a5f74ae3..b080c51c83a 100644
--- a/src/librustc_codegen_llvm/llvm/diagnostic.rs
+++ b/src/librustc_codegen_llvm/llvm/diagnostic.rs
@@ -77,7 +77,7 @@ impl OptimizationDiagnostic<'ll> {
             ).ok()
         ).ok();
 
-        let mut filename = filename.unwrap_or(String::new());
+        let mut filename = filename.unwrap_or_default();
         if filename.is_empty() {
             filename.push_str("<unknown file>");
         }