Add dangling impl

- Adds dangling impl diagnostics
- Rename validation test from dangling_impl to dangling_iml_ref

Author: Shourya742

src/tools/rust-analyzer/crates/syntax/src/validation.rs

@@ -37,6 +37,7 @@ pub(crate) fn validate(root: &SyntaxNode, errors: &mut Vec<SyntaxError>) {
                 ast::FnPtrType(it) => validate_trait_object_fn_ptr_ret_ty(it, errors),
                 ast::MacroRules(it) => validate_macro_rules(it, errors),
                 ast::LetExpr(it) => validate_let_expr(it, errors),
+                ast::ImplTraitType(it) => validate_impl_object_ty(it, errors),
                 _ => (),
             }
         }
@@ -315,21 +316,10 @@ fn validate_path_keywords(segment: ast::PathSegment, errors: &mut Vec<SyntaxErro
 }
 
 fn validate_trait_object_ref_ty(ty: ast::RefType, errors: &mut Vec<SyntaxError>) {
-    match ty.ty() {
-        Some(ast::Type::DynTraitType(ty)) => {
-            if let Some(err) = validate_trait_object_ty(ty) {
-                errors.push(err);
-            }
-        }
-        Some(ast::Type::ImplTraitType(ty)) => {
-            if ty.type_bound_list().map_or(0, |tbl| tbl.bounds().count()) == 0 {
-                errors.push(SyntaxError::new(
-                    "At least one trait must be specified",
-                    ty.syntax().text_range(),
-                ));
-            }
+    if let Some(ast::Type::DynTraitType(ty)) = ty.ty() {
+        if let Some(err) = validate_trait_object_ty(ty) {
+            errors.push(err);
         }
-        _ => {}
     }
 }
 
@@ -372,6 +362,15 @@ fn validate_trait_object_ty(ty: ast::DynTraitType) -> Option<SyntaxError> {
     }
 }
 
+fn validate_impl_object_ty(ty: ast::ImplTraitType, errors: &mut Vec<SyntaxError>) {
+    if ty.type_bound_list().map_or(0, |tbl| tbl.bounds().count()) == 0 {
+        errors.push(SyntaxError::new(
+            "At least one trait must be specified",
+            ty.syntax().text_range(),
+        ));
+    }
+}
+
 fn validate_macro_rules(mac: ast::MacroRules, errors: &mut Vec<SyntaxError>) {
     if let Some(vis) = mac.visibility() {
         errors.push(SyntaxError::new(

src/tools/rust-analyzer/crates/syntax/test_data/parser/validation/dangling_impl.rast

@@ -1,25 +1,23 @@
-SOURCE_FILE@0..17
-  FN@0..17
+SOURCE_FILE@0..16
+  FN@0..16
     [email protected] "fn"
     [email protected] " "
     [email protected]
       [email protected] "f"
-    PARAM_LIST@4..14
+    PARAM_LIST@4..13
       [email protected] "("
-      PARAM@5..13
+      PARAM@5..12
         [email protected]
           [email protected] "_"
         [email protected] ":"
         [email protected] " "
-        [email protected]
-          [email protected] "&"
-          [email protected]
-            [email protected] "impl"
-            [email protected]
-      [email protected] ")"
-    [email protected] " "
-    [email protected]
-      [email protected]
-        [email protected] "{"
-        [email protected] "}"
-error 9..13: At least one trait must be specified
+        [email protected]
+          [email protected] "impl"
+          [email protected]
+      [email protected] ")"
+    [email protected] " "
+    [email protected]
+      [email protected]
+        [email protected] "{"
+        [email protected] "}"
+error 8..12: At least one trait must be specified

src/tools/rust-analyzer/crates/syntax/test_data/parser/validation/dangling_impl.rs

@@ -1 +1 @@
-fn f(_: &impl) {}
+fn f(_: impl) {}

src/tools/rust-analyzer/crates/syntax/test_data/parser/validation/dangling_impl_reference.rast

@@ -0,0 +1,25 @@
+[email protected]
+  [email protected]
+    [email protected] "fn"
+    [email protected] " "
+    [email protected]
+      [email protected] "f"
+    [email protected]
+      [email protected] "("
+      [email protected]
+        [email protected]
+          [email protected] "_"
+        [email protected] ":"
+        [email protected] " "
+        [email protected]
+          [email protected] "&"
+          [email protected]
+            [email protected] "impl"
+            [email protected]
+      [email protected] ")"
+    [email protected] " "
+    [email protected]
+      [email protected]
+        [email protected] "{"
+        [email protected] "}"
+error 9..13: At least one trait must be specified

src/tools/rust-analyzer/crates/syntax/test_data/parser/validation/dangling_impl_reference.rs

@@ -0,0 +1 @@
+fn f(_: &impl) {}