Remove delayed typo expressions (#143423)

This removes the delayed typo correction functionality from Clang
(regular typo correction still remains) due to fragility of the
solution.

An RFC was posted here:
https://discourse.llvm.org/t/rfc-removing-support-for-delayed-typo-correction/86631
and while that RFC was asking for folks to consider stepping up to be
maintainers, and we did have a few new contributors show some interest,
experiments show that it's likely worth it to remove this functionality
entirely and focus efforts on improving regular typo correction.

This removal fixes ~20 open issues (quite possibly more), improves
compile time performance by roughly .3-.4%
(https://llvm-compile-time-tracker.com/?config=Overview&stat=instructions%3Au&remote=AaronBallman&sortBy=date),
and does not appear to regress diagnostic behavior in a way we wouldn't
find acceptable.

Fixes #142457
Fixes #139913
Fixes #138850
Fixes #137867
Fixes #137860
Fixes #107840
Fixes #93308
Fixes #69470
Fixes #59391
Fixes #58172
Fixes #46215
Fixes #45915
Fixes #45891
Fixes #44490
Fixes #36703
Fixes #32903
Fixes #23312
Fixes #69874

1 files changed, 3 insertions, 11 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 50f5757..923a9e8 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -535,12 +535,7 @@ Sema::ActOnCaseExpr(SourceLocation CaseLoc, ExprResult Val) {
     return ER;
   };
 
-  ExprResult Converted = CorrectDelayedTyposInExpr(
-      Val, /*InitDecl=*/nullptr, /*RecoverUncorrectedTypos=*/false,
-      CheckAndFinish);
-  if (Converted.get() == Val.get())
-    Converted = CheckAndFinish(Val.get());
-  return Converted;
+  return CheckAndFinish(Val.get());
 }
 
 StmtResult
@@ -2344,7 +2339,7 @@ StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
 static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init,
                                   SourceLocation Loc, int DiagID) {
   if (Decl->getType()->isUndeducedType()) {
-    ExprResult Res = SemaRef.CorrectDelayedTyposInExpr(Init);
+    ExprResult Res = Init;
     if (!Res.isUsable()) {
       Decl->setInvalidDecl();
       return true;
@@ -3845,10 +3840,7 @@ bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
 StmtResult
 Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                       Scope *CurScope) {
-  // Correct typos, in case the containing function returns 'auto' and
-  // RetValExp should determine the deduced type.
-  ExprResult RetVal = CorrectDelayedTyposInExpr(
-      RetValExp, nullptr, /*RecoverUncorrectedTypos=*/true);
+  ExprResult RetVal = RetValExp;
   if (RetVal.isInvalid())
     return StmtError();