getTypeAtLocation on a JSDoc @template type parameter dereferences a nil symbol #144

• Repository: pingdotgg/ts-rust
• Target commit: 2b0aaf111f15
• File: crates/ts_goport/src/checker/checker_p16.rs:695

Summary

A .ts file whose declaration carries @template T / @template {string} K loads fine, the type parameter is reachable with the real ast::get_node_at_position(..., true), and calling Checker::get_type_at_location on it panics with runtime error: invalid memory address or nil pointer dereference.

Affected code

crates/ts_goport/src/checker/checker_p16.rs:

  687              && self.sym(symbol).flags.intersects(SymbolFlags::EXPORT_VALUE)
  688              && self.sym(symbol).export_symbol.is_some()
  689          {
  690              symbol = self.sym(symbol).export_symbol;
  691          }
  692          self.get_merged_symbol(symbol)
  693      }
  694  
  695      // Go: checker/checker.go:14618 getSymbolOfDeclaration
  696      pub fn get_symbol_of_declaration(&mut self, node: Node) -> SymbolId {
  697          let symbol = node.symbol();
  698          if symbol.is_some() {
  699              let late = self.get_late_bound_symbol(symbol);
  700              return self.get_merged_symbol(late);
  701          }
  702          SymbolId::NIL
  703      }
  704  
  705      // Go: checker/checker.go:14628 getSymbolOfNode
  706      // Get the merged symbol for a node. If you know the node is a `Declaration`, it is more type safe to
  707      // use use `getSymbolOfDeclaration` instead.

Expected behavior

Every reachable helper dereference receives a non-null object or returns safely before the dereference.

Actual behavior

A .ts file whose declaration carries @template T / @template {string} K loads fine, the type parameter is reachable with the real ast::get_node_at_position(..., true), and calling Checker::get_type_at_location on it panics with runtime error: invalid memory address or nil pointer dereference. The sink is checker_p26.rs:762's go_nil_dereference() reached through get_declared_type_of_symbol; the JSDoc type parameter has no symbol in the file's symbol table.

How to reproduce

Load a .ts file with a JSDoc @template T on a declaration, resolve the type-parameter node, and call Checker::get_type_at_location; the process aborts with the nil-dereference panic.

Root cause

get_type_at_location takes the is_type_declaration branch for the type-parameter node and calls get_symbol_of_declaration; for a JSDoc-introduced @template parameter the binder records no symbol, so the result is nil and go_nil_dereference traps. The public checker path never guards this case (the callers that do work only use type parameters declared in .ts syntax, where a symbol exists).

Suggested fix

Guard the nil symbol in get_type_at_location/get_declared_type_of_symbol and return the declared type (or anyType) for JSDoc type parameters without a symbol. Add a checker test that loads a .ts file with @template and calls the public API on the type-parameter node.