Generalize -Wempty-body: warn when statement body is empty (closes: PR11329)

* if, switch, range-based for: warn if semicolon is on the same line.
* for, while: warn if semicolon is on the same line and either next
statement is compound statement or next statement has more
indentation.

Replacing the semicolon with {} or moving the semicolon to the next
line will always silence the warning.

Tests from SemaCXX/if-empty-body.cpp merged into SemaCXX/warn-empty-body.cpp.

llvm-svn: 150515

1 files changed, 20 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 68c938149ea..84063e5fd0f 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -8218,10 +8218,14 @@ void Sema::DefineImplicitCopyAssignment(SourceLocation CurrentLocation,
     CopyAssignOperator->setInvalidDecl();
     return;
   }
-  
-  StmtResult Body = ActOnCompoundStmt(Loc, Loc, move_arg(Statements),
-                                            /*isStmtExpr=*/false);
-  assert(!Body.isInvalid() && "Compound statement creation cannot fail");
+
+  StmtResult Body;
+  {
+    CompoundScopeRAII CompoundScope(*this);
+    Body = ActOnCompoundStmt(Loc, Loc, move_arg(Statements),
+                             /*isStmtExpr=*/false);
+    assert(!Body.isInvalid() && "Compound statement creation cannot fail");
+  }
   CopyAssignOperator->setBody(Body.takeAs<Stmt>());
 
   if (ASTMutationListener *L = getASTMutationListener()) {
@@ -8650,10 +8654,14 @@ void Sema::DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
     MoveAssignOperator->setInvalidDecl();
     return;
   }
-  
-  StmtResult Body = ActOnCompoundStmt(Loc, Loc, move_arg(Statements),
-                                            /*isStmtExpr=*/false);
-  assert(!Body.isInvalid() && "Compound statement creation cannot fail");
+
+  StmtResult Body;
+  {
+    CompoundScopeRAII CompoundScope(*this);
+    Body = ActOnCompoundStmt(Loc, Loc, move_arg(Statements),
+                             /*isStmtExpr=*/false);
+    assert(!Body.isInvalid() && "Compound statement creation cannot fail");
+  }
   MoveAssignOperator->setBody(Body.takeAs<Stmt>());
 
   if (ASTMutationListener *L = getASTMutationListener()) {
@@ -8852,9 +8860,10 @@ void Sema::DefineImplicitCopyConstructor(SourceLocation CurrentLocation,
       << CXXCopyConstructor << Context.getTagDeclType(ClassDecl);
     CopyConstructor->setInvalidDecl();
   }  else {
+    Sema::CompoundScopeRAII CompoundScope(*this);
     CopyConstructor->setBody(ActOnCompoundStmt(CopyConstructor->getLocation(),
                                                CopyConstructor->getLocation(),
-                                               MultiStmtArg(*this, 0, 0), 
+                                               MultiStmtArg(*this, 0, 0),
                                                /*isStmtExpr=*/false)
                                                               .takeAs<Stmt>());
     CopyConstructor->setImplicitlyDefined(true);
@@ -9006,9 +9015,10 @@ void Sema::DefineImplicitMoveConstructor(SourceLocation CurrentLocation,
       << CXXMoveConstructor << Context.getTagDeclType(ClassDecl);
     MoveConstructor->setInvalidDecl();
   }  else {
+    Sema::CompoundScopeRAII CompoundScope(*this);
     MoveConstructor->setBody(ActOnCompoundStmt(MoveConstructor->getLocation(),
                                                MoveConstructor->getLocation(),
-                                               MultiStmtArg(*this, 0, 0), 
+                                               MultiStmtArg(*this, 0, 0),
                                                /*isStmtExpr=*/false)
                                                               .takeAs<Stmt>());
     MoveConstructor->setImplicitlyDefined(true);