rationalize AbiConvErr better

Author: workingjubilee

compiler/rustc_abi/src/canon_abi.rs

@@ -6,7 +6,7 @@ use std::str::FromStr;
 #[cfg(feature = "nightly")]
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableOrd};
 
-use crate::{AbiFromStrErr, ExternAbi};
+use crate::{AbiConvErr, ExternAbi};
 
 /// Calling convention to determine codegen
 ///
@@ -137,7 +137,7 @@ impl CanonAbi {
     /// convert an ExternAbi to a CanonAbi if it maps directly
     ///
     /// Pretty incorrect to publicly expose!
-    const fn try_from_extern_abi(extern_abi: ExternAbi) -> Result<Self, AbiFromStrErr> {
+    const fn try_from_extern_abi(extern_abi: ExternAbi) -> Result<Self, AbiConvErr> {
         match extern_abi {
             ExternAbi::C { unwind: false } => Ok(Self::C),
             ExternAbi::Rust => Ok(Self::Rust),
@@ -173,7 +173,7 @@ impl CanonAbi {
             | ExternAbi::PtxKernel
             | ExternAbi::RustCall
             | ExternAbi::System { unwind: _ }
-            | ExternAbi::Unadjusted => Err(AbiFromStrErr::Unknown),
+            | ExternAbi::Unadjusted => Err(AbiConvErr::Unknown),
             // unwind where it should not unwind
             ExternAbi::Aapcs { unwind: true }
             | ExternAbi::C { unwind: true }
@@ -182,13 +182,13 @@ impl CanonAbi {
             | ExternAbi::Vectorcall { unwind: true }
             | ExternAbi::Thiscall { unwind: true }
             | ExternAbi::Win64 { unwind: true }
-            | ExternAbi::SysV64 { unwind: true } => Err(AbiFromStrErr::NoUnwind),
+            | ExternAbi::SysV64 { unwind: true } => Err(AbiConvErr::UnwindInvalid),
         }
     }
 }
 
 impl FromStr for CanonAbi {
-    type Err = AbiFromStrErr;
+    type Err = AbiConvErr;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         // parse as ExternAbi and propagate out errors, as CanonAbi uses the same errors

compiler/rustc_abi/src/extern_abi.rs

@@ -7,7 +7,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableOrd};
 #[cfg(feature = "nightly")]
 use rustc_macros::{Decodable, Encodable};
 
-use crate::AbiFromStrErr;
+use crate::AbiConvErr;
 
 #[cfg(test)]
 mod tests;
@@ -90,11 +90,11 @@ macro_rules! abi_impls {
         }
 
         impl ::core::str::FromStr for $e_name {
-            type Err = AbiFromStrErr;
+            type Err = AbiConvErr;
             fn from_str(s: &str) -> Result<$e_name, Self::Err> {
                 match s {
                     $($tok => Ok($e_name::$variant $({ unwind: $uw })*),)*
-                    _ => Err(AbiFromStrErr::Unknown),
+                    _ => Err(AbiConvErr::Unknown),
                 }
             }
         }

compiler/rustc_abi/src/extern_abi/tests.rs

@@ -19,7 +19,7 @@ fn lookup_cdecl() {
 #[test]
 fn lookup_baz() {
     let abi = ExternAbi::from_str("baz");
-    assert_matches!(abi, Err(AbiFromStrErr::Unknown));
+    assert_matches!(abi, Err(AbiConvErr::Unknown));
 }
 
 #[test]

compiler/rustc_abi/src/lib.rs

@@ -1897,10 +1897,12 @@ pub enum StructKind {
     Prefixed(Size, Align),
 }
 
+/// Errors in converting to or from an "Abi" type,
+/// relative to the conversion performed.
 #[derive(Clone, Debug)]
-pub enum AbiFromStrErr {
+pub enum AbiConvErr {
     /// not a known ABI
     Unknown,
-    /// no "-unwind" variant
-    NoUnwind,
+    /// "unwind" isn't valid
+    UnwindInvalid,
 }