cleanup(ops): simpler is_unit_result() (denoland#14586)

Rough token-string matching is robust enough and much easier to grok

.github/workflows/ci.yml

@@ -236,7 +236,7 @@ jobs:
  ~/.cargo/registry/index
  ~/.cargo/registry/cache
  ~/.cargo/git/db
- key: 12-cargo-home-${{ matrix.os }}-${{ hashFiles('Cargo.lock') }}
+ key: 13-cargo-home-${{ matrix.os }}-${{ hashFiles('Cargo.lock') }}
 
  # In main branch, always creates fresh cache
  - name: Cache build output (main)
@@ -252,7 +252,7 @@ jobs:
  !./target/*/*.zip
  !./target/*/*.tar.gz
  key: |
- 12-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-${{ github.sha }}
+ 13-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-${{ github.sha }}
 
  # Restore cache from the latest 'main' branch build.
  - name: Cache build output (PR)
@@ -268,7 +268,7 @@ jobs:
  !./target/*/*.tar.gz
  key: never_saved
  restore-keys: |
- 12-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-
+ 13-cargo-target-${{ matrix.os }}-${{ matrix.profile }}-
 
  # Don't save cache after building PRs or branches other than 'main'.
  - name: Skip save cache (PR)

ops/lib.rs

@@ -365,27 +365,8 @@ fn is_result(ty: impl ToTokens) -> bool {
 }
 
 /// Detects if a type is of the form Result<(), Err>
-fn is_unit_result(ty: &syn::Type) -> bool {
- let path = match ty {
- syn::Type::Path(ref path) => path,
- _ => return false,
- };
-
- let maybe_result = path.path.segments.first().expect("Invalid return type.");
- if maybe_result.ident != "Result" {
- return false;
- }
- assert!(!maybe_result.arguments.is_empty());
-
- let args = match &maybe_result.arguments {
- syn::PathArguments::AngleBracketed(args) => args,
- _ => unreachable!(),
- };
-
- match args.args.first().unwrap() {
- syn::GenericArgument::Type(syn::Type::Tuple(ty)) => ty.elems.is_empty(),
- _ => false,
- }
+fn is_unit_result(ty: impl ToTokens) -> bool {
+ is_result(&ty) && tokens(&ty).contains("Result < ()")
 }
 
 fn is_mut_ref_opstate(arg: &syn::FnArg) -> bool {