1 files changed, 23 insertions, 1 deletions

diff --git a/crates/ra_ssr/src/parsing.rs b/crates/ra_ssr/src/parsing.rs
index 2d6f4e514..769720bef 100644
--- a/crates/ra_ssr/src/parsing.rs
+++ b/crates/ra_ssr/src/parsing.rs
@@ -10,6 +10,7 @@ use crate::{SsrError, SsrPattern, SsrRule};
 use ra_syntax::{ast, AstNode, SmolStr, SyntaxKind, SyntaxNode, T};
 use rustc_hash::{FxHashMap, FxHashSet};
 use std::str::FromStr;
+use test_utils::mark;
 
 #[derive(Debug)]
 pub(crate) struct ParsedRule {
@@ -102,14 +103,35 @@ impl RuleBuilder {
         }
     }
 
-    fn build(self) -> Result<Vec<ParsedRule>, SsrError> {
+    fn build(mut self) -> Result<Vec<ParsedRule>, SsrError> {
         if self.rules.is_empty() {
             bail!("Not a valid Rust expression, type, item, path or pattern");
         }
+        // If any rules contain paths, then we reject any rules that don't contain paths. Allowing a
+        // mix leads to strange semantics, since the path-based rules only match things where the
+        // path refers to semantically the same thing, whereas the non-path-based rules could match
+        // anything. Specifically, if we have a rule like `foo ==>> bar` we only want to match the
+        // `foo` that is in the current scope, not any `foo`. However "foo" can be parsed as a
+        // pattern (BIND_PAT -> NAME -> IDENT). Allowing such a rule through would result in
+        // renaming everything called `foo` to `bar`. It'd also be slow, since without a path, we'd
+        // have to use the slow-scan search mechanism.
+        if self.rules.iter().any(|rule| contains_path(&rule.pattern)) {
+            let old_len = self.rules.len();
+            self.rules.retain(|rule| contains_path(&rule.pattern));
+            if self.rules.len() < old_len {
+                mark::hit!(pattern_is_a_single_segment_path);
+            }
+        }
         Ok(self.rules)
     }
 }
 
+/// Returns whether there are any paths in `node`.
+fn contains_path(node: &SyntaxNode) -> bool {
+    node.kind() == SyntaxKind::PATH
+        || node.descendants().any(|node| node.kind() == SyntaxKind::PATH)
+}
+
 impl FromStr for SsrRule {
     type Err = SsrError;