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 @@ pub trait ProcMacroExpander: fmt::Debug + Send + Sync + RefUnwindSafe {
     ) -> Result<Subtree, ProcMacroExpansionError>;
 }
 
+#[derive(Debug)]
 pub enum ProcMacroExpansionError {
     Panic(String),
     /// Things like "proc macro server was killed by OOM".

crates/ide-db/src/defs.rs

@@ -161,8 +161,8 @@ impl IdentClass {
                 ast::AwaitExpr(await_expr) => OperatorClass::classify_await(sema, &await_expr).map(IdentClass::Operator),
                 ast::BinExpr(bin_expr) => OperatorClass::classify_bin(sema, &bin_expr).map(IdentClass::Operator),
                 ast::IndexExpr(index_expr) => OperatorClass::classify_index(sema, &index_expr).map(IdentClass::Operator),
-                ast::PrefixExpr(prefix_expr) => OperatorClass::classify_prefix(sema,&prefix_expr).map(IdentClass::Operator),
-                ast::TryExpr(try_expr) => OperatorClass::classify_try(sema,&try_expr).map(IdentClass::Operator),
+                ast::PrefixExpr(prefix_expr) => OperatorClass::classify_prefix(sema, &prefix_expr).map(IdentClass::Operator),
+                ast::TryExpr(try_expr) => OperatorClass::classify_try(sema, &try_expr).map(IdentClass::Operator),
                 _ => None,
             }
         }

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;
+                        IdentClass::Operator(OperatorClass::Await(_)) => None,
+
+                        IdentClass::NameRefClass(NameRefClass::ExternCrateShorthand {
+                            decl,
+                            ..
+                        }) => Some(vec![(Definition::ExternCrateDecl(decl), node)]),
+
+                        class => Some(
+                            class
+                                .definitions()
+                                .into_iter()
+                                .zip(iter::repeat(node))
+                                .collect::<Vec<_>>(),
+                        ),
                     }
-                    if let IdentClass::NameRefClass(NameRefClass::ExternCrateShorthand {
-                        decl,
-                        ..
-                    }) = class
-                    {
-                        return Some(vec![(Definition::ExternCrateDecl(decl), node)]);
-                    }
-                    Some(
-                        class
-                            .definitions()
-                            .into_iter()
-                            .zip(iter::once(node).cycle())
-                            .collect::<Vec<_>>(),
-                    )
                 })
                 .flatten()
                 .unique_by(|&(def, _)| def)