Fix random segfaults in Github runner

cpp2rust/converter/mapper.cpp

@@ -32,6 +32,7 @@ std::unordered_map<std::string, TranslationRule::TypeTgt>
 clang::PrintingPolicy getPrintPolicy() {
   assert(ctx_);
   clang::PrintingPolicy policy(ctx_->getLangOpts());
+  policy.Bool = true;
   policy.SuppressTagKeyword = true;
   policy.SuppressScope = false;
   policy.FullyQualifiedName = true;
@@ -562,6 +563,11 @@ std::string normalizeTranslationRule(std::string rule) {
 
 } // namespace
 
+PushASTContext::PushASTContext(clang::ASTContext &ctx) : prev_(ctx_) {
+  ctx_ = &ctx;
+}
+PushASTContext::~PushASTContext() { ctx_ = prev_; }
+
 bool Contains(clang::QualType qual_type) {
   return search(qual_type) != types_.end();
 }

cpp2rust/converter/mapper.h

@@ -3,6 +3,7 @@
 // Copyright (c) 2022-present INESC-ID.
 // Distributed under the MIT license that can be found in the LICENSE file.
 
+#include <clang/AST/ASTContext.h>
 #include <clang/AST/Expr.h>
 #include <clang/AST/Type.h>
 
@@ -14,6 +15,17 @@
 #include "converter/translation_rule.h"
 
 namespace cpp2rust::Mapper {
+class PushASTContext {
+public:
+  explicit PushASTContext(clang::ASTContext &ctx);
+  ~PushASTContext();
+  PushASTContext(const PushASTContext &) = delete;
+  PushASTContext &operator=(const PushASTContext &) = delete;
+
+private:
+  clang::ASTContext *prev_;
+};
+
 bool Contains(clang::QualType qual_type);
 bool Contains(const clang::Expr *expr);
 

cpp2rust/converter/translation_rule.cpp

@@ -86,6 +86,7 @@ class Callback : public clang::ast_matchers::MatchFinder::MatchCallback {
 
   void run(const clang::ast_matchers::MatchFinder::MatchResult &R) override {
     assert(sema_);
+    Mapper::PushASTContext scoped(*R.Context);
     if (auto var = R.Nodes.getNodeAs<clang::TypeAliasDecl>("tvar")) {
       clang::QualType type;
       if (auto *tdecl = var->getDescribedAliasTemplate()) {