Use enum_select for generating diag::FunModes structure

Author: Igor S. Gerasimov

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -714,8 +714,9 @@ def err_thread_unsupported : Error<
   "thread-local storage is not supported for the current target">;
 
 def warn_falloff_nonvoid : Warning<
-  "non-void %select{function|block|lambda|coroutine}0 "
-  "does not return a value%select{| in all control paths}1">,
+  "non-void "
+  "%enum_select<FunModes>{%Function{function}|%Block{block}|%Lambda{lambda}|%Coroutine{coroutine}}0"
+  " does not return a value%select{| in all control paths}1">,
   InGroup<ReturnType>;
 def err_falloff_nonvoid : Error<
   "non-void %select{function|block|lambda|coroutine}0 "

clang/lib/Sema/AnalysisBasedWarnings.cpp

@@ -547,7 +547,7 @@ struct CheckFallThroughDiagnostics {
   unsigned diag_FallThrough_HasNoReturn;
   unsigned diag_FallThrough_ReturnsNonVoid;
   unsigned diag_NeverFallThroughOrReturn;
-  enum { Function = 0, Block, Lambda, Coroutine } funMode;
+  unsigned funMode; // TODO: use diag::FunModes
   SourceLocation FuncLoc;
 
   static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
@@ -572,7 +572,7 @@ struct CheckFallThroughDiagnostics {
     else
       D.diag_NeverFallThroughOrReturn = 0;
 
-    D.funMode = Function;
+    D.funMode = diag::FunModes::Function;
     return D;
   }
 
@@ -582,7 +582,7 @@ struct CheckFallThroughDiagnostics {
     D.diag_FallThrough_HasNoReturn = 0;
     D.diag_FallThrough_ReturnsNonVoid = diag::warn_falloff_nonvoid;
     D.diag_NeverFallThroughOrReturn = 0;
-    D.funMode = Coroutine;
+    D.funMode = diag::FunModes::Coroutine;
     return D;
   }
 
@@ -591,7 +591,7 @@ struct CheckFallThroughDiagnostics {
     D.diag_FallThrough_HasNoReturn = diag::err_noreturn_has_return_expr;
     D.diag_FallThrough_ReturnsNonVoid = diag::err_falloff_nonvoid;
     D.diag_NeverFallThroughOrReturn = 0;
-    D.funMode = Block;
+    D.funMode = diag::FunModes::Block;
     return D;
   }
 
@@ -600,13 +600,13 @@ struct CheckFallThroughDiagnostics {
     D.diag_FallThrough_HasNoReturn = diag::err_noreturn_has_return_expr;
     D.diag_FallThrough_ReturnsNonVoid = diag::warn_falloff_nonvoid;
     D.diag_NeverFallThroughOrReturn = 0;
-    D.funMode = Lambda;
+    D.funMode = diag::FunModes::Lambda;
     return D;
   }
 
   bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
                         bool HasNoReturn) const {
-    if (funMode == Function) {
+    if (funMode == diag::FunModes::Function) {
       return (ReturnsVoid ||
               D.isIgnored(diag::warn_falloff_nonvoid, FuncLoc)) &&
              (!HasNoReturn ||
@@ -615,7 +615,7 @@ struct CheckFallThroughDiagnostics {
              (!ReturnsVoid ||
               D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
     }
-    if (funMode == Coroutine) {
+    if (funMode == diag::FunModes::Coroutine) {
       return (ReturnsVoid ||
               D.isIgnored(diag::warn_falloff_nonvoid, FuncLoc)) &&
              (!HasNoReturn);

clang/lib/Sema/SemaStmt.cpp

@@ -3590,7 +3590,7 @@ StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
 
   if (auto *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) {
     if (CurBlock->FunctionType->castAs<FunctionType>()->getNoReturnAttr()) {
-      Diag(ReturnLoc, diag::err_noreturn_has_return_expr) << 1;
+      Diag(ReturnLoc, diag::err_noreturn_has_return_expr) << diag::FunModes::Block;
       return StmtError();
     }
   } else if (auto *CurRegion = dyn_cast<CapturedRegionScopeInfo>(CurCap)) {
@@ -3601,7 +3601,7 @@ StmtResult Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc,
     if (CurLambda->CallOperator->getType()
             ->castAs<FunctionType>()
             ->getNoReturnAttr()) {
-      Diag(ReturnLoc, diag::err_noreturn_has_return_expr) << 2;
+      Diag(ReturnLoc, diag::err_noreturn_has_return_expr) << diag::FunModes::Lambda;
       return StmtError();
     }
   }