Auto merge of rust-lang#13952 - WaffleLapkin:either_ast_node2, r=lnicola

minor: Use the fact that `Either`: `AstNode`

Continuation of rust-lang/rust-analyzer#13949

Author: bors

crates/ide-assists/src/handlers/convert_named_struct_to_tuple_struct.rs

@@ -52,10 +52,7 @@ pub(crate) fn convert_named_struct_to_tuple_struct(
     acc: &mut Assists,
     ctx: &AssistContext<'_>,
 ) -> Option<()> {
-    let strukt = ctx
-        .find_node_at_offset::<ast::Struct>()
-        .map(Either::Left)
-        .or_else(|| ctx.find_node_at_offset::<ast::Variant>().map(Either::Right))?;
+    let strukt = ctx.find_node_at_offset::<Either<ast::Struct, ast::Variant>>()?;
     let field_list = strukt.as_ref().either(|s| s.field_list(), |v| v.field_list())?;
     let record_fields = match field_list {
         ast::FieldList::RecordFieldList(it) => it,

crates/ide-assists/src/handlers/convert_tuple_struct_to_named_struct.rs

@@ -50,10 +50,7 @@ pub(crate) fn convert_tuple_struct_to_named_struct(
     acc: &mut Assists,
     ctx: &AssistContext<'_>,
 ) -> Option<()> {
-    let strukt = ctx
-        .find_node_at_offset::<ast::Struct>()
-        .map(Either::Left)
-        .or_else(|| ctx.find_node_at_offset::<ast::Variant>().map(Either::Right))?;
+    let strukt = ctx.find_node_at_offset::<Either<ast::Struct, ast::Variant>>()?;
     let field_list = strukt.as_ref().either(|s| s.field_list(), |v| v.field_list())?;
     let tuple_fields = match field_list {
         ast::FieldList::TupleFieldList(it) => it,

crates/ide-assists/src/handlers/extract_type_alias.rs

@@ -1,9 +1,6 @@
 use either::Either;
 use ide_db::syntax_helpers::node_ext::walk_ty;
-use syntax::{
-    ast::{self, edit::IndentLevel, make, AstNode, HasGenericParams, HasName},
-    match_ast,
-};
+use syntax::ast::{self, edit::IndentLevel, make, AstNode, HasGenericParams, HasName};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
@@ -31,15 +28,8 @@ pub(crate) fn extract_type_alias(acc: &mut Assists, ctx: &AssistContext<'_>) ->
 
     let ty = ctx.find_node_at_range::<ast::Type>()?;
     let item = ty.syntax().ancestors().find_map(ast::Item::cast)?;
-    let assoc_owner = item.syntax().ancestors().nth(2).and_then(|it| {
-        match_ast! {
-            match it {
-                ast::Trait(tr) => Some(Either::Left(tr)),
-                ast::Impl(impl_) => Some(Either::Right(impl_)),
-                _ => None,
-            }
-        }
-    });
+    let assoc_owner =
+        item.syntax().ancestors().nth(2).and_then(Either::<ast::Trait, ast::Impl>::cast);
     let node = assoc_owner.as_ref().map_or_else(
         || item.syntax(),
         |impl_| impl_.as_ref().either(AstNode::syntax, AstNode::syntax),

crates/ide-assists/src/handlers/reorder_fields.rs

@@ -20,10 +20,7 @@ use crate::{AssistContext, AssistId, AssistKind, Assists};
 // const test: Foo = Foo {foo: 1, bar: 0}
 // ```
 pub(crate) fn reorder_fields(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
-    let record = ctx
-        .find_node_at_offset::<ast::RecordExpr>()
-        .map(Either::Left)
-        .or_else(|| ctx.find_node_at_offset::<ast::RecordPat>().map(Either::Right))?;
+    let record = ctx.find_node_at_offset::<Either<ast::RecordExpr, ast::RecordPat>>()?;
 
     let path = record.as_ref().either(|it| it.path(), |it| it.path())?;
     let ranks = compute_fields_ranks(&path, ctx)?;

crates/ide/src/hover.rs

@@ -230,15 +230,8 @@ fn hover_ranged(
     config: &HoverConfig,
 ) -> Option<RangeInfo<HoverResult>> {
     // FIXME: make this work in attributes
-    let expr_or_pat = file.covering_element(range).ancestors().find_map(|it| {
-        match_ast! {
-            match it {
-                ast::Expr(expr) => Some(Either::Left(expr)),
-                ast::Pat(pat) => Some(Either::Right(pat)),
-                _ => None,
-            }
-        }
-    })?;
+    let expr_or_pat =
+        file.covering_element(range).ancestors().find_map(Either::<ast::Expr, ast::Pat>::cast)?;
     let res = match &expr_or_pat {
         Either::Left(ast::Expr::TryExpr(try_expr)) => render::try_expr(sema, config, try_expr),
         Either::Left(ast::Expr::PrefixExpr(prefix_expr))