[AST] Forbid copy/move of statements/types.

[riccibruno]

Summary

Statements, expressions and types are not supposed to be copied/moved, and trying to do so is only going to result in tears. Someone tripped on this a few days ago on the mailing list. NFC.

[lebedev.ri]

Probably Decl too?

[riccibruno]

In D60123#1451303, @lebedev.ri wrote:

Probably Decl too?

Yep. I though it was already done but after checking it seems I remembered incorrectly.

[riccibruno]

In D60123#1451307, @riccibruno wrote:

In D60123#1451303, @lebedev.ri wrote:

Probably Decl too?

Yep. I though it was already done but after checking it seems I remembered incorrectly.

Huh, never mind. It seems that at least ImplicitParamDecls are used in a SmallVector, and this requires the copy-constructor to be usable.

[aaron.ballman]

LGTM

include/clang/AST/Stmt.h

Stmt(StmtClass SC) {
     StmtBits.IsOMPStructuredBlock = false;
     if (StatisticsEnabled) Stmt::addStmtClass(SC);
   }
 
   StmtClass getStmtClass() const {
     return static_cast<StmtClass>(StmtBits.sClass);
   }
 
+  Stmt(const Stmt &) = delete;
+  Stmt(Stmt &&) = delete;
+  Stmt &operator=(const Stmt &) = delete;
+  Stmt &operator=(Stmt &&) = delete;
+
   const char *getStmtClassName() const;
 
   bool isOMPStructuredBlock() const { return StmtBits.IsOMPStructuredBlock; }
   void setIsOMPStructuredBlock(bool IsOMPStructuredBlock) {
     StmtBits.IsOMPStructuredBlock = IsOMPStructuredBlock;
   }
 
   /// SourceLocation tokens are not useful in isolation - they are low level