Auto merge of #15660 - DaniPopes:hover-simple-refactor, r=HKalbasi

minor: hover_simple refactor

A minor refactor of `hover_simple` opportunity I noticed while skimming through the code.

- `if let`s -> `match`
- `iter::once(x).cycle` -> `iter::repeat`
- `classify_token` -> `classify_node`

crates/base-db/src/input.rs

@@ -257,6 +257,7 @@ fn expand(
     ) -> Result<Subtree, ProcMacroExpansionError>;
 }
 
+#[derive(Debug)]
 pub enum ProcMacroExpansionError {
     Panic(String),
     /// Things like "proc macro server was killed by OOM".

crates/ide/src/hover.rs

@@ -180,26 +180,24 @@ fn hover_simple(
             descended()
                 .filter_map(|token| {
                     let node = token.parent()?;
-                    let class = IdentClass::classify_token(sema, token)?;
-                    if let IdentClass::Operator(OperatorClass::Await(_)) = class {
+                    match IdentClass::classify_node(sema, &node)? {
                         // It's better for us to fall back to the keyword hover here,
                         // rendering poll is very confusing
-                        return None;
-                    }
-                    if let IdentClass::NameRefClass(NameRefClass::ExternCrateShorthand {
+                        IdentClass::Operator(OperatorClass::Await(_)) => None,
+
+                        IdentClass::NameRefClass(NameRefClass::ExternCrateShorthand {
                             decl,
                             ..
-                    }) = class
-                    {
-                        return Some(vec![(Definition::ExternCrateDecl(decl), node)]);
-                    }
-                    Some(
+                        }) => Some(vec![(Definition::ExternCrateDecl(decl), node)]),
+
+                        class => Some(
                             class
                                 .definitions()
                                 .into_iter()
-                            .zip(iter::once(node).cycle())
+                                .zip(iter::repeat(node))
                                 .collect::<Vec<_>>(),
-                    )
+                        ),
+                    }
                 })
                 .flatten()
                 .unique_by(|&(def, _)| def)