[AST] NFC: Remove DelayedDiag from ErrorTypeRepr

This is no longer used.

Author: hamishknight

include/swift/AST/TypeRepr.h

@@ -216,36 +216,24 @@ class alignas(1 << TypeReprAlignInBits) TypeRepr
 /// A TypeRepr for a type with a syntax error.  Can be used both as a
 /// top-level TypeRepr and as a part of other TypeRepr.
 ///
-/// The client can either emit a detailed diagnostic at the construction time
-/// (in the parser) or store a zero-arg diagnostic in this TypeRepr to be
-/// emitted after parsing, during type resolution.
-///
 /// All uses of this type should be ignored and not re-diagnosed.
 class ErrorTypeRepr : public TypeRepr {
   SourceRange Range;
-  std::optional<ZeroArgDiagnostic> DelayedDiag;
 
-  ErrorTypeRepr(SourceRange Range, std::optional<ZeroArgDiagnostic> Diag)
-      : TypeRepr(TypeReprKind::Error), Range(Range), DelayedDiag(Diag) {}
+  ErrorTypeRepr(SourceRange Range)
+      : TypeRepr(TypeReprKind::Error), Range(Range) {}
 
 public:
   static ErrorTypeRepr *
-  create(ASTContext &Context, SourceRange Range,
-         std::optional<ZeroArgDiagnostic> DelayedDiag = std::nullopt) {
-    assert((!DelayedDiag || Range) && "diagnostic needs a location");
-    return new (Context) ErrorTypeRepr(Range, DelayedDiag);
+  create(ASTContext &Context, SourceRange Range) {
+    return new (Context) ErrorTypeRepr(Range);
   }
 
   static ErrorTypeRepr *
-  create(ASTContext &Context, SourceLoc Loc = SourceLoc(),
-         std::optional<ZeroArgDiagnostic> DelayedDiag = std::nullopt) {
-    return create(Context, SourceRange(Loc), DelayedDiag);
+  create(ASTContext &Context, SourceLoc Loc = SourceLoc()) {
+    return create(Context, SourceRange(Loc));
   }
 
-  /// If there is a delayed diagnostic stored in this TypeRepr, consumes and
-  /// emits that diagnostic.
-  void dischargeDiagnostic(ASTContext &Context);
-
   static bool classof(const TypeRepr *T) {
     return T->getKind() == TypeReprKind::Error;
   }

lib/AST/TypeRepr.cpp

@@ -970,15 +970,6 @@ void IntegerTypeRepr::printImpl(ASTPrinter &Printer,
   Printer.printText(getValue());
 }
 
-void ErrorTypeRepr::dischargeDiagnostic(swift::ASTContext &Context) {
-  if (!DelayedDiag)
-    return;
-
-  // Consume and emit the diagnostic.
-  Context.Diags.diagnose(Range.Start, *DelayedDiag).highlight(Range);
-  DelayedDiag = std::nullopt;
-}
-
 // See swift/Basic/Statistic.h for declaration: this enables tracing
 // TypeReprs, is defined here to avoid too much layering violation / circular
 // linkage dependency.

lib/Sema/TypeCheckType.cpp

@@ -2766,7 +2766,6 @@ NeverNullType TypeResolver::resolveType(TypeRepr *repr,
 
   switch (repr->getKind()) {
   case TypeReprKind::Error:
-    cast<ErrorTypeRepr>(repr)->dischargeDiagnostic(getASTContext());
     return ErrorType::get(getASTContext());
 
   case TypeReprKind::Attributed: