Statically prove uninhabitedness

time-rs · Dec 15, 2024 · dad76cb · dad76cb
1 parent 16b436b
commit dad76cb
Show file tree

Hide file tree

Showing 3 changed files with 20 additions and 15 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -122,8 +122,9 @@ unwrap-in-result = "warn"
 unwrap-used = "warn"
 use-debug = "warn"
 
-option-if-let-else = { level = "allow", priority = 1 }  # suggests terrible code, overrides #![warn(clippy::nursery)]
-redundant-pub-crate = { level = "allow", priority = 1 } # rust-lang/rust-clippy#5369, overrides #![warn(clippy::nursery)]
+option-if-let-else = { level = "allow", priority = 1 }     # suggests terrible code, overrides #![warn(clippy::nursery)]
+redundant-pub-crate = { level = "allow", priority = 1 }    # rust-lang/rust-clippy#5369, overrides #![warn(clippy::nursery)]
+uninhabited-references = { level = "allow", priority = 1 } # rust-lang/rust-clippy#11984
 
 [workspace.lints.rustdoc]
 private-doc-tests = "warn"

diff --git a/time/src/error/mod.rs b/time/src/error/mod.rs
@@ -17,6 +17,7 @@ mod parse_from_description;
 #[cfg(feature = "parsing")]
 mod try_from_parsed;
 
+use core::convert::Infallible;
 use core::fmt;
 
 pub use component_range::ComponentRange;
@@ -36,9 +37,6 @@ pub use parse_from_description::ParseFromDescription;
 #[cfg(feature = "parsing")]
 pub use try_from_parsed::TryFromParsed;
 
-#[cfg(feature = "parsing")]
-use crate::internal_macros::bug;
-
 /// A unified error type for anything returned by a method in the time crate.
 ///
 /// This can be used when you either don't know or don't care about the exact error returned.
@@ -66,7 +64,10 @@ pub enum Error {
         since = "0.3.28",
         note = "no longer output. moved to the `ParseFromDescription` variant"
     )]
-    UnexpectedTrailingCharacters,
+    UnexpectedTrailingCharacters {
+        #[doc(hidden)]
+        never: Infallible,
+    },
     #[cfg(feature = "parsing")]
     #[allow(missing_docs)]
     TryFromParsed(TryFromParsed),
@@ -92,7 +93,7 @@ impl fmt::Display for Error {
             Self::ParseFromDescription(e) => e.fmt(f),
             #[cfg(feature = "parsing")]
             #[allow(deprecated)]
-            Self::UnexpectedTrailingCharacters => bug!("variant should not be used"),
+            Self::UnexpectedTrailingCharacters { never } => match *never {},
             #[cfg(feature = "parsing")]
             Self::TryFromParsed(e) => e.fmt(f),
             #[cfg(all(any(feature = "formatting", feature = "parsing"), feature = "alloc"))]
@@ -117,7 +118,7 @@ impl std::error::Error for Error {
             Self::ParseFromDescription(err) => Some(err),
             #[cfg(feature = "parsing")]
             #[allow(deprecated)]
-            Self::UnexpectedTrailingCharacters => bug!("variant should not be used"),
+            Self::UnexpectedTrailingCharacters { never } => match *never {},
             #[cfg(feature = "parsing")]
             Self::TryFromParsed(err) => Some(err),
             #[cfg(all(any(feature = "formatting", feature = "parsing"), feature = "alloc"))]

diff --git a/time/src/error/parse.rs b/time/src/error/parse.rs
@@ -1,9 +1,9 @@
 //! Error that occurred at some stage of parsing
 
+use core::convert::Infallible;
 use core::fmt;
 
 use crate::error::{self, ParseFromDescription, TryFromParsed};
-use crate::internal_macros::bug;
 
 /// An error that occurred at some stage of parsing.
 #[non_exhaustive]
@@ -13,13 +13,16 @@ pub enum Parse {
     TryFromParsed(TryFromParsed),
     #[allow(missing_docs)]
     ParseFromDescription(ParseFromDescription),
-    /// The input should have ended, but there were characters remaining.
+    #[allow(missing_docs)]
     #[non_exhaustive]
     #[deprecated(
         since = "0.3.28",
         note = "no longer output. moved to the `ParseFromDescription` variant"
     )]
-    UnexpectedTrailingCharacters,
+    UnexpectedTrailingCharacters {
+        #[doc(hidden)]
+        never: Infallible,
+    },
 }
 
 impl fmt::Display for Parse {
@@ -28,7 +31,7 @@ impl fmt::Display for Parse {
             Self::TryFromParsed(err) => err.fmt(f),
             Self::ParseFromDescription(err) => err.fmt(f),
             #[allow(deprecated)]
-            Self::UnexpectedTrailingCharacters => bug!("variant should not be used"),
+            Self::UnexpectedTrailingCharacters { never } => match *never {},
         }
     }
 }
@@ -40,7 +43,7 @@ impl std::error::Error for Parse {
             Self::TryFromParsed(err) => Some(err),
             Self::ParseFromDescription(err) => Some(err),
             #[allow(deprecated)]
-            Self::UnexpectedTrailingCharacters => bug!("variant should not be used"),
+            Self::UnexpectedTrailingCharacters { never } => match *never {},
         }
     }
 }
@@ -85,7 +88,7 @@ impl From<Parse> for crate::Error {
             Parse::TryFromParsed(err) => Self::TryFromParsed(err),
             Parse::ParseFromDescription(err) => Self::ParseFromDescription(err),
             #[allow(deprecated)]
-            Parse::UnexpectedTrailingCharacters => bug!("variant should not be used"),
+            Parse::UnexpectedTrailingCharacters { never } => match never {},
         }
     }
 }
@@ -97,7 +100,7 @@ impl TryFrom<crate::Error> for Parse {
         match err {
             crate::Error::ParseFromDescription(err) => Ok(Self::ParseFromDescription(err)),
             #[allow(deprecated)]
-            crate::Error::UnexpectedTrailingCharacters => bug!("variant should not be used"),
+            crate::Error::UnexpectedTrailingCharacters { never } => match never {},
             crate::Error::TryFromParsed(err) => Ok(Self::TryFromParsed(err)),
             _ => Err(error::DifferentVariant),
         }