fix: only special casing 3 colon in a row

Author: yue4u

crates/ide-completion/src/context.rs

@@ -573,15 +573,17 @@ impl<'a> CompletionContext<'a> {
         // this approach works in normal path and inside token tree
         match original_token.kind() {
             T![:] => {
-                // return if no prev token before colon
+                // no prev token before colon
                 let prev_token = original_token.prev_token()?;
 
                 // only has a single colon
                 if prev_token.kind() != T![:] {
                     return None;
                 }
 
-                if !is_prev_token_valid_path_start_or_segment(&prev_token) {
+                // has 3 colon in a row
+                // special casing this as per discussion in https://github.com/rust-lang/rust-analyzer/pull/13611#discussion_r1031845205
+                if prev_token.prev_token().map(|t| t.kind() == T![:]).unwrap_or(false) {
                     return None;
                 }
             }
@@ -637,24 +639,6 @@ impl<'a> CompletionContext<'a> {
     }
 }
 
-fn is_prev_token_valid_path_start_or_segment(token: &SyntaxToken) -> bool {
-    if let Some(prev_token) = token.prev_token() {
-        // token before coloncolon is invalid
-        if !matches!(
-            prev_token.kind(),
-            // trival
-            WHITESPACE | COMMENT
-            // PathIdentSegment
-            | IDENT | T![super] | T![self] | T![Self] | T![crate]
-            // QualifiedPath
-            | T![>]
-        ) {
-            return false;
-        }
-    }
-    true
-}
-
 const OP_TRAIT_LANG_NAMES: &[&str] = &[
     "add_assign",
     "add",

crates/ide-completion/src/tests/special.rs

@@ -967,16 +967,10 @@ fn foo { crate:$0 }
 }
 
 #[test]
-fn no_completions_in_invalid_path() {
+fn no_completions_in_after_tripple_colon() {
     check(
         r#"
 fn foo { crate:::$0 }
-"#,
-        expect![""],
-    );
-    check(
-        r#"
-fn foo { crate::::$0 }
 "#,
         expect![""],
     );