refactor(fe): delete unused user_diag_reporter_ code

user_diag_reporter_ is always a Null_Diag_Reporter. Stop calling
Null_Diag_Reporter::report_impl (which does nothing).

src/quick-lint-js/fe/lex.cpp

@@ -230,7 +230,6 @@ Lexer::Lexer(Padded_String_View input)
 
 Lexer::Lexer(Padded_String_View input, Lexer_Options options)
     : input_(input.data()),
-      user_diag_reporter_(&Null_Diag_Reporter::instance),
       original_input_(input),
       options_(options) {
   this->last_token_.end = this->input_;
@@ -265,8 +264,6 @@ void Lexer::parse_bom_before_shebang() {
   while (!this->try_parse_current_token()) {
     // Loop.
   }
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 bool Lexer::try_parse_current_token() {
@@ -1063,8 +1060,6 @@ void Lexer::skip_in_jsx() {
     }
     break;
   }
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 void Lexer::skip_in_jsx_children() {
@@ -1244,8 +1239,6 @@ void Lexer::reparse_as_regexp() {
 
   this->input_ = c;
   this->last_token_.end = this->input_;
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 Lexer_Transaction Lexer::begin_transaction() {
@@ -1266,8 +1259,6 @@ void Lexer::commit_transaction(Lexer_Transaction&& transaction) {
   this->diag_reporter_ = transaction.old_diag_reporter;
 
   transaction.reporter.reset();
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 void Lexer::roll_back_transaction(Lexer_Transaction&& transaction) {
@@ -2307,8 +2298,6 @@ void Lexer::skip_jsx_text() {
 done:
   // TODO(strager): Should we set has_leading_newline?
   this->input_ = c;
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 bool Lexer::is_eof(const Char8* input) const {

src/quick-lint-js/fe/lex.h

@@ -342,25 +342,9 @@ class Lexer {
 
   static Token_Type identifier_token_type(String8_View);
 
- public:
-  // TODO(#1154): Delete this.
-  void flush_diags_to_user_reporter_if_needed() {
-    int i = 0;
-    this->diags().for_each([&](Diag_Type diag_type, void* diag_data) {
-      if (i >= this->diags_reporter_to_user_) {
-        this->user_diag_reporter_->report_impl(diag_type, diag_data);
-        this->diags_reporter_to_user_ += 1;
-      }
-      i += 1;
-    });
-  }
-
- private:
   Token last_token_;
   const Char8* last_last_token_end_;
   const Char8* input_;
-  Diag_Reporter* user_diag_reporter_;  // TODO(#1154): Delete.
-  int diags_reporter_to_user_ = 0;     // TODO(#1154): Delete.
   Padded_String_View original_input_;
   Lexer_Options options_;
 

src/quick-lint-js/fe/parse-expression.cpp

@@ -347,9 +347,7 @@ Expression* Parser::parse_expression(Parse_Visitor_Base& v, Precedence prec) {
   if (!prec.binary_operators && prec.math_or_logical_or_assignment) {
     return ast;
   }
-  ast = this->parse_expression_remainder(v, ast, prec);
-  this->flush_diags_to_user_reporter_if_needed();
-  return ast;
+  return this->parse_expression_remainder(v, ast, prec);
 }
 
 // TODO(strager): Why do we need precedence here? Could we get rid of prec?

src/quick-lint-js/fe/parse-statement.cpp

@@ -70,7 +70,6 @@ void Parser::parse_and_visit_module(Parse_Visitor_Base &v) {
   }
   this->check_all_jsx_attributes();
   v.visit_end_of_module();
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 bool Parser::parse_and_visit_statement(Parse_Visitor_Base &v,
@@ -785,7 +784,6 @@ bool Parser::parse_and_visit_statement(Parse_Visitor_Base &v,
 
   case Token_Type::end_of_file:
   case Token_Type::right_curly:
-    this->flush_diags_to_user_reporter_if_needed();
     // Do not set is_current_typescript_namespace_non_empty_.
     return false;
 
@@ -794,7 +792,6 @@ bool Parser::parse_and_visit_statement(Parse_Visitor_Base &v,
     break;
   }
 
-  this->flush_diags_to_user_reporter_if_needed();
   return true;
 }
 
@@ -1684,7 +1681,6 @@ void Parser::parse_and_visit_typescript_generic_parameters(
           });
     }
     this->skip();
-    this->flush_diags_to_user_reporter_if_needed();
     return;
   }
   for (const Source_Code_Span &comma : leading_commas) {
@@ -1909,8 +1905,6 @@ void Parser::parse_and_visit_typescript_generic_parameters(
 
   // See NOTE[generic-type-parameter-visit-order].
   extends_visits.visitor().move_into(v);
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 void Parser::parse_and_visit_statement_block_no_scope(Parse_Visitor_Base &v) {

src/quick-lint-js/fe/parse-type.cpp

@@ -911,8 +911,6 @@ void Parser::parse_and_visit_typescript_type_expression_no_scope(
                .parse_question_as_invalid = false,
            });
   }
-
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 void Parser::parse_and_visit_typescript_arrow_type_expression(

src/quick-lint-js/fe/parse.cpp

@@ -965,7 +965,6 @@ void Parser::commit_transaction(Parser_Transaction&& transaction) {
   this->diag_reporter_ = transaction.old_diag_reporter;
 
   this->lexer_.commit_transaction(std::move(transaction.lex_transaction));
-  this->flush_diags_to_user_reporter_if_needed();
 }
 
 void Parser::roll_back_transaction(Parser_Transaction&& transaction) {

src/quick-lint-js/fe/parse.h

@@ -127,13 +127,6 @@ class Parser {
     return this->lexer_.diag_list_diag_reporter();
   }
 
- private:
-  // TODO(#1154): Delete this.
-  void flush_diags_to_user_reporter_if_needed() {
-    this->lexer_.flush_diags_to_user_reporter_if_needed();
-  }
-
- public:
   // For testing and internal use only.
   [[nodiscard]] Function_Guard enter_function(Function_Attributes);
 
@@ -179,7 +172,6 @@ class Parser {
             break;
           }
 
-          this->flush_diags_to_user_reporter_if_needed();
           return false;
         });
 
@@ -859,8 +851,6 @@ class Parser {
       auto disable_guard = alloc.disable();
       this->visit_expression(ast, v, Variable_Context::rhs);
     }
-
-    this->flush_diags_to_user_reporter_if_needed();
   }
 
   Expression *parse_expression(Parse_Visitor_Base &, Precedence);