add ssr fragment for statements

Author: matklad

crates/ide_ssr/src/fragments.rs

@@ -19,7 +19,7 @@ pub(crate) fn ty(s: &str) -> Result<SyntaxNode, ()> {
     if node.to_string() != s {
         return Err(());
     }
-    Ok(node.syntax().clone())
+    Ok(node.syntax().clone_subtree())
 }
 
 pub(crate) fn item(s: &str) -> Result<SyntaxNode, ()> {
@@ -33,7 +33,7 @@ pub(crate) fn item(s: &str) -> Result<SyntaxNode, ()> {
     if node.to_string() != s {
         return Err(());
     }
-    Ok(node.syntax().clone())
+    Ok(node.syntax().clone_subtree())
 }
 
 pub(crate) fn expr(s: &str) -> Result<SyntaxNode, ()> {
@@ -47,5 +47,24 @@ pub(crate) fn expr(s: &str) -> Result<SyntaxNode, ()> {
     if node.to_string() != s {
         return Err(());
     }
-    Ok(node.syntax().clone())
+    Ok(node.syntax().clone_subtree())
+}
+
+pub(crate) fn stmt(s: &str) -> Result<SyntaxNode, ()> {
+    let template = "const _: () = { {}; };";
+    let input = template.replace("{}", s);
+    let parse = syntax::SourceFile::parse(&input);
+    if !parse.errors().is_empty() {
+        return Err(());
+    }
+    let mut node =
+        parse.tree().syntax().descendants().skip(2).find_map(ast::Stmt::cast).ok_or(())?;
+    if !s.ends_with(';') && node.to_string().ends_with(';') {
+        node = node.clone_for_update();
+        node.syntax().last_token().map(|it| it.detach());
+    }
+    if node.to_string() != s {
+        return Err(());
+    }
+    Ok(node.syntax().clone_subtree())
 }

crates/ide_ssr/src/parsing.rs

@@ -73,17 +73,17 @@ impl ParsedRule {
             rules: Vec::new(),
         };
 
-        let raw_template_stmt = raw_template.map(ast::Stmt::parse);
+        let raw_template_stmt = raw_template.map(fragments::stmt);
         if let raw_template_expr @ Some(Ok(_)) = raw_template.map(fragments::expr) {
             builder.try_add2(fragments::expr(&raw_pattern), raw_template_expr);
         } else {
-            builder.try_add(ast::Expr::parse(&raw_pattern), raw_template_stmt.clone());
+            builder.try_add2(fragments::expr(&raw_pattern), raw_template_stmt.clone());
         }
         builder.try_add2(fragments::ty(&raw_pattern), raw_template.map(fragments::ty));
         builder.try_add2(fragments::item(&raw_pattern), raw_template.map(fragments::item));
         builder.try_add(ast::Path::parse(&raw_pattern), raw_template.map(ast::Path::parse));
         builder.try_add(ast::Pat::parse(&raw_pattern), raw_template.map(ast::Pat::parse));
-        builder.try_add(ast::Stmt::parse(&raw_pattern), raw_template_stmt);
+        builder.try_add2(fragments::stmt(&raw_pattern), raw_template_stmt);
         builder.build()
     }
 }