Substitute type parameters with type aliases

Enable customization of the template instantiation
process in unit tests.

Author: robertoraggi

src/parser/cxx/ast_rewriter.cc

@@ -3457,6 +3457,18 @@ auto ASTRewriter::SpecifierVisitor::operator()(NamedTypeSpecifierAST* ast)
   copy->isTemplateIntroduced = ast->isTemplateIntroduced;
   copy->symbol = ast->symbol;
 
+  if (auto typeParameter = symbol_cast<TypeParameterSymbol>(copy->symbol)) {
+    const auto& args = rewrite.templateArguments_;
+    if (typeParameter && typeParameter->depth() == 0 &&
+        typeParameter->index() < args.size()) {
+      auto index = typeParameter->index();
+
+      if (auto sym = std::get_if<Symbol*>(&args[index])) {
+        copy->symbol = *sym;
+      }
+    }
+  }
+
   return copy;
 }
 

src/parser/cxx/binder.cc

@@ -661,6 +661,8 @@ auto Binder::resolve(NestedNameSpecifierAST* nestedNameSpecifier,
 }
 
 auto Binder::instantiate(SimpleTemplateIdAST* templateId) -> Symbol* {
+  if (!translationUnit()->config().templateInstantiation) return nullptr;
+
   std::vector<TemplateArgument> args;
   for (auto it = templateId->templateArgumentList; it; it = it->next) {
     if (auto arg = ast_cast<TypeTemplateArgumentAST>(it->value)) {

src/parser/cxx/decl_specs.cc

@@ -256,21 +256,6 @@ void DeclSpecs::Visitor::operator()(ComplexTypeSpecifierAST* ast) {
 void DeclSpecs::Visitor::operator()(NamedTypeSpecifierAST* ast) {
   specs.typeSpecifier = ast;
 
-  if (specs.rewriter) {
-    auto typeParameter = symbol_cast<TypeParameterSymbol>(ast->symbol);
-    const auto& args = specs.rewriter->templateArguments();
-
-    if (typeParameter && typeParameter->depth() == 0 &&
-        typeParameter->index() < args.size()) {
-      auto index = typeParameter->index();
-
-      if (auto ty = std::get_if<const Type*>(&args[index])) {
-        specs.type = *ty;
-        return;
-      }
-    }
-  }
-
   if (ast->symbol)
     specs.type = ast->symbol->type();
   else

src/parser/cxx/parser.cc

@@ -268,10 +268,8 @@ auto Parser::expect(TokenKind tk, SourceLocation& location) -> bool {
 
 void Parser::operator()(UnitAST*& ast) { parse(ast); }
 
-auto Parser::config() const -> const ParserConfiguration& { return config_; }
-
-void Parser::setConfig(ParserConfiguration config) {
-  config_ = std::move(config);
+auto Parser::config() const -> const ParserConfiguration& {
+  return unit->config();
 }
 
 void Parser::parse(UnitAST*& ast) { parse_translation_unit(ast); }
@@ -676,7 +674,7 @@ auto Parser::parse_completion(SourceLocation& loc) -> bool {
   if (didAcceptCompletionToken_) return false;
 
   // if there is no completer, return false
-  if (!config_.complete) return false;
+  if (!config().complete) return false;
 
   if (!match(TokenKind::T_CODE_COMPLETION, loc)) return false;
 
@@ -709,7 +707,7 @@ auto Parser::parse_primary_expression(ExpressionAST*& yyast,
 }
 
 auto Parser::parse_splicer(SplicerAST*& yyast) -> bool {
-  if (!config_.reflect) return false;
+  if (!config().reflect) return false;
 
   if (!lookat(TokenKind::T_LBRACKET, TokenKind::T_COLON)) return false;
 
@@ -729,7 +727,7 @@ auto Parser::parse_splicer(SplicerAST*& yyast) -> bool {
 
 auto Parser::parse_splicer_expression(ExpressionAST*& yyast,
                                       const ExprContext& ctx) -> bool {
-  if (!config_.reflect) return false;
+  if (!config().reflect) return false;
 
   SplicerAST* splicer = nullptr;
   if (!parse_splicer(splicer)) return false;
@@ -741,7 +739,7 @@ auto Parser::parse_splicer_expression(ExpressionAST*& yyast,
 
 auto Parser::parse_reflect_expression(ExpressionAST*& yyast,
                                       const ExprContext& ctx) -> bool {
-  if (!config_.reflect) return false;
+  if (!config().reflect) return false;
 
   SourceLocation caretLoc;
 
@@ -1054,7 +1052,7 @@ auto Parser::parse_template_nested_name_specifier(
     }
   }
 
-  if (!ast->symbol && config_.checkTypes) {
+  if (!ast->symbol && config().checkTypes) {
     ast->symbol = binder_.instantiate(templateId);
   }
 
@@ -1859,7 +1857,7 @@ auto Parser::parse_member_expression(ExpressionAST*& yyast) -> bool {
       auto objectType = ast->baseExpression->type;
 
       // trigger the completion
-      config_.complete(MemberCompletionContext{
+      config().complete(MemberCompletionContext{
           .objectType = objectType,
           .accessOp = ast->accessOp,
       });
@@ -4082,7 +4080,7 @@ auto Parser::parse_simple_declaration(
 
     if (auto scope = decl.getScope()) {
       setScope(scope);
-    } else if (q && config_.checkTypes) {
+    } else if (q && config().checkTypes) {
       parse_error(q->firstSourceLocation(),
                   std::format("unresolved class or namespace"));
     }
@@ -4091,7 +4089,7 @@ auto Parser::parse_simple_declaration(
     auto functionSymbol = getFunction(scope(), functionName, functionType);
 
     if (!functionSymbol) {
-      if (q && config_.checkTypes) {
+      if (q && config().checkTypes) {
         parse_error(q->firstSourceLocation(),
                     std::format("class or namespace has no member named '{}'",
                                 to_string(functionName)));
@@ -4196,7 +4194,7 @@ auto Parser::parse_notypespec_function_definition(
   if (auto scope = decl.getScope()) {
     setScope(scope);
   } else if (auto q = decl.getNestedNameSpecifier()) {
-    if (config_.checkTypes) {
+    if (config().checkTypes) {
       parse_error(q->firstSourceLocation(),
                   std::format("unresolved class or namespace"));
     }
@@ -4325,7 +4323,7 @@ auto Parser::parse_static_assert_declaration(DeclarationAST*& yyast) -> bool {
       value = visit(to_bool, *constValue);
     }
 
-    if (!value && config_.checkTypes) {
+    if (!value && config().checkTypes) {
       SourceLocation loc = ast->firstSourceLocation();
 
       if (!ast->expression || !constValue.has_value()) {
@@ -4847,12 +4845,12 @@ auto Parser::parse_named_type_specifier(SpecifierAST*& yyast, DeclSpecs& specs)
     if (conceptSymbol && !lookat(TokenKind::T_AUTO)) return false;
   }
 
-  const auto canInstantiate = config_.checkTypes;
+  const auto canInstantiate = config().checkTypes;
 
   auto symbol =
       binder_.resolve(nestedNameSpecifier, unqualifiedId, canInstantiate);
 
-  if (config_.checkTypes && !symbol && ast_cast<NameIdAST>(unqualifiedId)) {
+  if (config().checkTypes && !symbol && ast_cast<NameIdAST>(unqualifiedId)) {
     return false;
   }
 
@@ -4987,14 +4985,14 @@ auto Parser::parse_primitive_type_specifier(SpecifierAST*& yyast,
 }
 
 auto Parser::maybe_template_name(const Identifier* id) -> bool {
-  if (!config_.fuzzyTemplateResolution) return true;
+  if (!config().fuzzyTemplateResolution) return true;
   if (template_names_.contains(id)) return true;
   if (concept_names_.contains(id)) return true;
   return false;
 }
 
 void Parser::mark_maybe_template_name(const Identifier* id) {
-  if (!config_.fuzzyTemplateResolution) return;
+  if (!config().fuzzyTemplateResolution) return;
   if (!id) return;
   template_names_.insert(id);
 }
@@ -5314,7 +5312,7 @@ auto Parser::parse_declarator(DeclaratorAST*& yyast, Decl& decl,
 
   if (auto scope = decl.getScope()) {
     setScope(scope);
-  } else if (q && config_.checkTypes) {
+  } else if (q && config().checkTypes) {
     parse_error(q->firstSourceLocation(),
                 std::format("unresolved class or namespace"));
   }
@@ -9041,7 +9039,7 @@ auto Parser::parse_concept_definition(DeclarationAST*& yyast) -> bool {
 
 auto Parser::parse_splicer_specifier(SpecifierAST*& yyast, DeclSpecs& specs)
     -> bool {
-  if (!config_.reflect) return false;
+  if (!config().reflect) return false;
   if (specs.typeSpecifier) return false;
   LookaheadParser lookahead{this};
   SourceLocation typenameLoc;
@@ -9391,7 +9389,7 @@ void Parser::check(ExpressionAST* ast) {
   if (binder_.inTemplate()) return;
   TypeChecker check{unit};
   check.setScope(scope());
-  check.setReportErrors(config_.checkTypes);
+  check.setReportErrors(config().checkTypes);
   check(ast);
 }
 

src/parser/cxx/parser.h

@@ -69,7 +69,6 @@ class Parser final {
   void operator()(UnitAST*& ast);
 
   [[nodiscard]] auto config() const -> const ParserConfiguration&;
-  void setConfig(ParserConfiguration config);
 
  private:
   struct TemplateHeadContext;
@@ -111,7 +110,7 @@ class Parser final {
 
   [[nodiscard]] auto shouldStopParsing() const -> bool {
     if (didAcceptCompletionToken_) return true;
-    if (config_.stopParsingPredicate) return config_.stopParsingPredicate();
+    if (config().stopParsingPredicate) return config().stopParsingPredicate();
     return false;
   }
 
@@ -804,7 +803,6 @@ class Parser final {
   DiagnosticsClient* diagnosticClient_ = nullptr;
   Scope* globalScope_ = nullptr;
   Binder binder_;
-  ParserConfiguration config_{};
   bool skipFunctionBody_ = false;
   bool moduleUnit_ = false;
   const Identifier* moduleId_ = nullptr;

src/parser/cxx/parser_fwd.h

@@ -47,6 +47,7 @@ using CodeCompletionContext =
 struct ParserConfiguration {
   bool checkTypes = false;
   bool fuzzyTemplateResolution = false;
+  bool templateInstantiation = true;
   bool reflect = true;
   std::function<bool()> stopParsingPredicate;
   std::function<void(const CodeCompletionContext&)> complete;

src/parser/cxx/translation_unit.cc

@@ -167,12 +167,18 @@ void TranslationUnit::parse(ParserConfiguration config) {
   if (ast_) {
     cxx_runtime_error("translation unit already parsed");
   }
+
+  config_ = std::move(config);
+
   preprocessor_->squeeze();
   Parser parse(this);
-  parse.setConfig(std::move(config));
   parse(ast_);
 }
 
+auto TranslationUnit::config() const -> const ParserConfiguration& {
+  return config_;
+}
+
 auto TranslationUnit::globalScope() const -> Scope* {
   if (!globalNamespace_) return nullptr;
   return globalNamespace_->scope();

src/parser/cxx/translation_unit.h

@@ -68,6 +68,8 @@ class TranslationUnit {
 
   void parse(ParserConfiguration config = {});
 
+  [[nodiscard]] auto config() const -> const ParserConfiguration&;
+
   // set source and preprocess, deprecated.
   void setSource(std::string source, std::string fileName);
 
@@ -137,6 +139,7 @@ class TranslationUnit {
   const char* yyptr = nullptr;
   DiagnosticsClient* diagnosticsClient_ = nullptr;
   NamespaceSymbol* globalNamespace_ = nullptr;
+  ParserConfiguration config_;
 };
 
 }  // namespace cxx