Emit a warning when the body of an if block is a NullStmt.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@42840 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Sema/SemaStmt.cpp b/Sema/SemaStmt.cpp
index b6d4c55..460b50c 100644
--- a/Sema/SemaStmt.cpp
+++ b/Sema/SemaStmt.cpp
@@ -173,6 +173,8 @@
StmtTy *ThenVal, SourceLocation ElseLoc,
StmtTy *ElseVal) {
Expr *condExpr = (Expr *)CondVal;
+ Stmt *thenStmt = (Stmt *)ThenVal;
+
assert(condExpr && "ActOnIfStmt(): missing expression");
DefaultFunctionArrayConversion(condExpr);
@@ -182,7 +184,16 @@
return Diag(IfLoc, diag::err_typecheck_statement_requires_scalar,
condType.getAsString(), condExpr->getSourceRange());
- return new IfStmt(IfLoc, condExpr, (Stmt*)ThenVal, (Stmt*)ElseVal);
+ // Warn if the if block has a null body without an else value.
+ // this helps prevent bugs due to typos, such as
+ // if (condition);
+ // do_stuff();
+ if (!ElseVal) {
+ if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt))
+ Diag(stmt->getSemiLoc(), diag::warn_empty_if_body);
+ }
+
+ return new IfStmt(IfLoc, condExpr, thenStmt, (Stmt*)ElseVal);
}
Action::StmtResult