1 files changed, 81 insertions, 60 deletions

diff --git a/crates/ra_syntax/src/validation.rs b/crates/ra_syntax/src/validation.rs
index f0b3dec63..fdec48fb0 100644
--- a/crates/ra_syntax/src/validation.rs
+++ b/crates/ra_syntax/src/validation.rs
@@ -2,15 +2,15 @@
 
 mod block;
 
-use std::convert::TryFrom;
-
-use rustc_lexer::unescape;
-
 use crate::{
     ast, match_ast, AstNode, SyntaxError,
     SyntaxKind::{BYTE, BYTE_STRING, CHAR, CONST_DEF, FN_DEF, INT_NUMBER, STRING, TYPE_ALIAS_DEF},
     SyntaxNode, SyntaxToken, TextSize, T,
 };
+use rustc_lexer::unescape::{
+    self, unescape_byte, unescape_byte_literal, unescape_char, unescape_literal, Mode,
+};
+use std::convert::TryFrom;
 
 fn rustc_unescape_error_to_string(err: unescape::EscapeError) -> &'static str {
     use unescape::EscapeError as EE;
@@ -54,7 +54,7 @@ fn rustc_unescape_error_to_string(err: unescape::EscapeError) -> &'static str {
             "Unicode escape must not be empty"
         }
         EE::UnclosedUnicodeEscape => {
-            "Missing '}' to terminate the unicode escape"
+            "Missing `}` to terminate the unicode escape"
         }
         EE::LeadingUnderscoreUnicodeEscape => {
             "Unicode escape code must not begin with an underscore"
@@ -81,10 +81,8 @@ fn rustc_unescape_error_to_string(err: unescape::EscapeError) -> &'static str {
 
 pub(crate) fn validate(root: &SyntaxNode) -> Vec<SyntaxError> {
     // FIXME:
-    // * Add validation of character literal containing only a single char
-    // * Add validation of `crate` keyword not appearing in the middle of the symbol path
+    // * Add unescape validation of raw string literals and raw byte string literals
     // * Add validation of doc comments are being attached to nodes
-    // * Remove validation of unterminated literals (it is already implemented in `tokenize()`)
 
     let mut errors = Vec::new();
     for node in root.descendants() {
@@ -96,7 +94,7 @@ pub(crate) fn validate(root: &SyntaxNode) -> Vec<SyntaxError> {
                 ast::RecordField(it) => validate_numeric_name(it.name_ref(), &mut errors),
                 ast::Visibility(it) => validate_visibility(it, &mut errors),
                 ast::RangeExpr(it) => validate_range_expr(it, &mut errors),
-                ast::PathSegment(it) => validate_crate_keyword_in_path_segment(it, &mut errors),
+                ast::PathSegment(it) => validate_path_keywords(it, &mut errors),
                 _ => (),
             }
         }
@@ -121,18 +119,18 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
 
     match token.kind() {
         BYTE => {
-            if let Some(Err(e)) = unquote(text, 2, '\'').map(unescape::unescape_byte) {
+            if let Some(Err(e)) = unquote(text, 2, '\'').map(unescape_byte) {
                 push_err(2, e);
             }
         }
         CHAR => {
-            if let Some(Err(e)) = unquote(text, 1, '\'').map(unescape::unescape_char) {
+            if let Some(Err(e)) = unquote(text, 1, '\'').map(unescape_char) {
                 push_err(1, e);
             }
         }
         BYTE_STRING => {
             if let Some(without_quotes) = unquote(text, 2, '"') {
-                unescape::unescape_byte_str(without_quotes, &mut |range, char| {
+                unescape_byte_literal(without_quotes, Mode::ByteStr, &mut |range, char| {
                     if let Err(err) = char {
                         push_err(2, (range.start, err));
                     }
@@ -141,7 +139,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
         }
         STRING => {
             if let Some(without_quotes) = unquote(text, 1, '"') {
-                unescape::unescape_str(without_quotes, &mut |range, char| {
+                unescape_literal(without_quotes, Mode::Str, &mut |range, char| {
                     if let Err(err) = char {
                         push_err(1, (range.start, err));
                     }
@@ -224,59 +222,82 @@ fn validate_range_expr(expr: ast::RangeExpr, errors: &mut Vec<SyntaxError>) {
     }
 }
 
-fn validate_crate_keyword_in_path_segment(
-    segment: ast::PathSegment,
-    errors: &mut Vec<SyntaxError>,
-) {
-    const ERR_MSG: &str = "The `crate` keyword is only allowed as the first segment of a path";
+fn validate_path_keywords(segment: ast::PathSegment, errors: &mut Vec<SyntaxError>) {
+    use ast::PathSegmentKind;
 
-    let crate_token = match segment.crate_token() {
-        None => return,
-        Some(it) => it,
-    };
+    let path = segment.parent_path();
+    let is_path_start = segment.coloncolon_token().is_none() && path.qualifier().is_none();
 
-    // Disallow both ::crate and foo::crate
-    let mut path = segment.parent_path();
-    if segment.coloncolon_token().is_some() || path.qualifier().is_some() {
-        errors.push(SyntaxError::new(ERR_MSG, crate_token.text_range()));
-        return;
+    if let Some(token) = segment.self_token() {
+        if !is_path_start {
+            errors.push(SyntaxError::new(
+                "The `self` keyword is only allowed as the first segment of a path",
+                token.text_range(),
+            ));
+        }
+    } else if let Some(token) = segment.crate_token() {
+        if !is_path_start || use_prefix(path).is_some() {
+            errors.push(SyntaxError::new(
+                "The `crate` keyword is only allowed as the first segment of a path",
+                token.text_range(),
+            ));
+        }
+    } else if let Some(token) = segment.super_token() {
+        if !all_supers(&path) {
+            errors.push(SyntaxError::new(
+                "The `super` keyword may only be preceded by other `super`s",
+                token.text_range(),
+            ));
+            return;
+        }
+
+        let mut curr_path = path;
+        while let Some(prefix) = use_prefix(curr_path) {
+            if !all_supers(&prefix) {
+                errors.push(SyntaxError::new(
+                    "The `super` keyword may only be preceded by other `super`s",
+                    token.text_range(),
+                ));
+                return;
+            }
+            curr_path = prefix;
+        }
     }
 
-    // For expressions and types, validation is complete, but we still have
-    // to handle invalid UseItems like this:
-    //
-    //      use foo:{crate::bar::baz};
-    //
-    // To handle this we must inspect the parent `UseItem`s and `UseTree`s
-    // but right now we're looking deep inside the nested `Path` nodes because
-    // `Path`s are left-associative:
-    //
-    //   ((crate)::bar)::baz)
-    //       ^ current value of path
-    //
-    // So we need to climb to the top
-    while let Some(parent) = path.parent_path() {
-        path = parent;
+    fn use_prefix(mut path: ast::Path) -> Option<ast::Path> {
+        for node in path.syntax().ancestors().skip(1) {
+            match_ast! {
+                match node {
+                    ast::UseTree(it) => if let Some(tree_path) = it.path() {
+                        // Even a top-level path exists within a `UseTree` so we must explicitly
+                        // allow our path but disallow anything else
+                        if tree_path != path {
+                            return Some(tree_path);
+                        }
+                    },
+                    ast::UseTreeList(_it) => continue,
+                    ast::Path(parent) => path = parent,
+                    _ => return None,
+                }
+            };
+        }
+        return None;
     }
 
-    // Now that we've found the whole path we need to see if there's a prefix
-    // somewhere in the UseTree hierarchy. This check is arbitrarily deep
-    // because rust allows arbitrary nesting like so:
-    //
-    // use {foo::{{{{crate::bar::baz}}}}};
-    for node in path.syntax().ancestors().skip(1) {
-        match_ast! {
-            match node {
-                ast::UseTree(it) => if let Some(tree_path) = it.path() {
-                    // Even a top-level path exists within a `UseTree` so we must explicitly
-                    // allow our path but disallow anything else
-                    if tree_path != path {
-                        errors.push(SyntaxError::new(ERR_MSG, crate_token.text_range()));
-                    }
-                },
-                ast::UseTreeList(_it) => continue,
-                _ => return,
-            }
+    fn all_supers(path: &ast::Path) -> bool {
+        let segment = match path.segment() {
+            Some(it) => it,
+            None => return false,
         };
+
+        if segment.kind() != Some(PathSegmentKind::SuperKw) {
+            return false;
+        }
+
+        if let Some(ref subpath) = path.qualifier() {
+            return all_supers(subpath);
+        }
+
+        return true;
     }
 }