Various small code review improvements

crates/ra_hir/src/expr.rs

@@ -1,3 +1,4 @@
+use std::ops::Index;
 use std::sync::Arc;
 
 use rustc_hash::FxHashMap;
@@ -44,14 +45,6 @@ pub struct BodySyntaxMapping {
 }
 
 impl Body {
-    pub fn expr(&self, expr: ExprId) -> &Expr {
-        &self.exprs[expr]
-    }
-
-    pub fn pat(&self, pat: PatId) -> &Pat {
-        &self.pats[pat]
-    }
-
     pub fn args(&self) -> &[PatId] {
         &self.args
     }
@@ -61,6 +54,22 @@ impl Body {
     }
 }
 
+impl Index<ExprId> for Body {
+    type Output = Expr;
+
+    fn index(&self, expr: ExprId) -> &Expr {
+        &self.exprs[expr]
+    }
+}
+
+impl Index<PatId> for Body {
+    type Output = Pat;
+
+    fn index(&self, pat: PatId) -> &Pat {
+        &self.pats[pat]
+    }
+}
+
 impl BodySyntaxMapping {
     pub fn expr_syntax(&self, expr: ExprId) -> Option<LocalSyntaxPtr> {
         self.expr_syntax_mapping_back.get(&expr).cloned()
@@ -377,11 +386,7 @@ impl ExprCollector {
                         syntax_ptr,
                     )
                 } else {
-                    let condition = if let Some(condition) = e.condition() {
-                        self.collect_expr_opt(condition.expr())
-                    } else {
-                        self.exprs.alloc(Expr::Missing)
-                    };
+                    let condition = self.collect_expr_opt(e.condition().and_then(|c| c.expr()));
                     let then_branch = self.collect_block_opt(e.then_branch());
                     let else_branch = e.else_branch().map(|e| self.collect_block(e));
                     self.alloc_expr(

crates/ra_hir/src/function/scope.rs

@@ -66,8 +66,7 @@ impl FnScopes {
             .scope_chain_for(context_expr)
             .flat_map(|scope| self.entries(scope).iter())
             .filter(|entry| shadowed.insert(entry.name()))
-            .filter(|entry| entry.name() == &name)
-            .nth(0);
+            .find(|entry| entry.name() == &name);
         ret
     }
 
@@ -84,7 +83,7 @@ impl FnScopes {
         })
     }
     fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
-        match body.pat(pat) {
+        match &body[pat] {
             Pat::Bind { name } => self.scopes[scope].entries.push(ScopeEntry {
                 name: name.clone(),
                 pat,
@@ -96,7 +95,7 @@ impl FnScopes {
         let body = Arc::clone(&self.body);
         params
             .into_iter()
-            .for_each(|it| self.add_bindings(&body, scope, *it));
+            .for_each(|pat| self.add_bindings(&body, scope, *pat));
     }
     fn set_scope(&mut self, node: ExprId, scope: ScopeId) {
         self.scope_for.insert(node, scope);
@@ -218,8 +217,7 @@ impl ScopesWithSyntaxMapping {
         node.ancestors()
             .map(LocalSyntaxPtr::new)
             .filter_map(|ptr| self.syntax_mapping.syntax_expr(ptr))
-            .filter_map(|it| self.scopes.scope_for(it))
-            .next()
+            .find_map(|it| self.scopes.scope_for(it))
     }
 }
 
@@ -264,7 +262,7 @@ fn compute_block_scopes(
 
 fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut FnScopes, scope: ScopeId) {
     scopes.set_scope(expr, scope);
-    match body.expr(expr) {
+    match &body[expr] {
         Expr::Block { statements, tail } => {
             compute_block_scopes(&statements, *tail, body, scopes, scope);
         }

crates/ra_hir/src/source_binder.rs

@@ -92,12 +92,10 @@ pub fn function_from_position(
     position: FilePosition,
 ) -> Cancelable<Option<Function>> {
     let file = db.source_file(position.file_id);
-    let fn_def = if let Some(f) = find_node_at_offset::<ast::FnDef>(file.syntax(), position.offset)
-    {
-        f
-    } else {
-        return Ok(None);
-    };
+    let fn_def = ctry!(find_node_at_offset::<ast::FnDef>(
+        file.syntax(),
+        position.offset
+    ));
     function_from_source(db, position.file_id, fn_def)
 }