[Sema] Cosolidate suppress diagnostics mechanisms

TypeCheckExprFlags::SuppressDiagnostics is now done by
DiagnosticSuppression.

Author: rintaro

lib/Sema/TypeCheckConstraints.cpp

@@ -2142,7 +2142,7 @@ class FallbackDiagnosticListener : public ExprTypeCheckListener {
 
   void maybeProduceFallbackDiagnostic(Expr *expr) const {
     if (Options.contains(TypeCheckExprFlags::SubExpressionDiagnostics) ||
-        Options.contains(TypeCheckExprFlags::SuppressDiagnostics))
+        DiagnosticSuppression::isEnabled(TC.Diags))
       return;
 
     // Before producing fatal error here, let's check if there are any "error"
@@ -2184,8 +2184,7 @@ Type TypeChecker::typeCheckExpressionImpl(Expr *&expr, DeclContext *dc,
   // Construct a constraint system from this expression.
   ConstraintSystemOptions csOptions = ConstraintSystemFlags::AllowFixes;
 
-  if (options.contains(TypeCheckExprFlags::SuppressDiagnostics) ||
-      DiagnosticSuppression::isEnabled(Diags))
+  if (DiagnosticSuppression::isEnabled(Diags))
     csOptions |= ConstraintSystemFlags::SuppressDiagnostics;
 
   if (options.contains(TypeCheckExprFlags::AllowUnresolvedTypeVariables))

lib/Sema/TypeCheckStmt.cpp

@@ -24,6 +24,7 @@
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/DiagnosticsSema.h"
+#include "swift/AST/DiagnosticSuppression.h"
 #include "swift/AST/Identifier.h"
 #include "swift/AST/Initializer.h"
 #include "swift/AST/NameLookup.h"
@@ -1942,10 +1943,10 @@ static Expr* constructCallToSuperInit(ConstructorDecl *ctor,
     r = new (Context) TryExpr(SourceLoc(), r, Type(), /*implicit=*/true);
 
   TypeChecker &tc = *static_cast<TypeChecker *>(Context.getLazyResolver());
+  DiagnosticSuppression suppression(tc.Diags);
   auto resultTy =
       tc.typeCheckExpression(r, ctor, TypeLoc(), CTP_Unused,
-                             TypeCheckExprFlags::IsDiscarded |
-                               TypeCheckExprFlags::SuppressDiagnostics);
+                             TypeCheckExprFlags::IsDiscarded);
   if (!resultTy)
     return nullptr;
 

lib/Sema/TypeChecker.cpp

@@ -705,8 +705,7 @@ bool swift::typeCheckExpression(DeclContext *DC, Expr *&parsedExpr) {
   TypeChecker &TC = createTypeChecker(ctx);
 
   auto resultTy = TC.typeCheckExpression(parsedExpr, DC, TypeLoc(),
-                                    ContextualTypePurpose::CTP_Unused,
-                                    TypeCheckExprFlags::SuppressDiagnostics);
+                                         ContextualTypePurpose::CTP_Unused);
   return !resultTy;
 }
 

lib/Sema/TypeChecker.h

@@ -235,9 +235,6 @@ enum class TypeCheckExprFlags {
   /// that we force for style or other reasons.
   DisableStructuralChecks = 0x02,
 
-  /// Set if the client wants diagnostics suppressed.
-  SuppressDiagnostics = 0x04,
-
   /// If set, the client wants a best-effort solution to the constraint system,
   /// but can tolerate a solution where all of the constraints are solved, but
   /// not all type variables have been determined.  In this case, the constraint