[PATCH] D81163: [AST][RecoveryExpr] Preserve the AST for invalid conditions.

[Haojian Wu via Phabricator via cfe-commits]

hokein created this revision.
hokein added a reviewer: sammccall.
Herald added a project: clang.

Tested with enabling "-frecovery-ast", only 1 failure, which is
an improvement of secondary diagnostic.

  --
  error: 'error' diagnostics seen but not expected:
    File /workspace/llvm-project/clang/test/SemaTemplate/instantiate-expr-3.cpp Line 68: invalid operands to binary expression ('N1::X' and 'int')
  1 error generated.
  
  --


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D81163

Files:
  clang/lib/Sema/SemaExpr.cpp
  clang/test/AST/ast-dump-recovery.cpp


Index: clang/test/AST/ast-dump-recovery.cpp
===================================================================
--- clang/test/AST/ast-dump-recovery.cpp
+++ clang/test/AST/ast-dump-recovery.cpp
@@ -211,3 +211,30 @@
 } NoCrashOnInvalidInitList = {
   .abc = nullptr,
 };
+
+void InvalidCondition() {
+  // CHECK:      IfStmt {{.*}}
+  // CHECK-NEXT: |-RecoveryExpr {{.*}} <col:7, col:15> '<dependent type>' contains-errors
+  // CHECK-NEXT: | `-UnresolvedLookupExpr {{.*}} <col:7>
+  if (invalid()) {}
+
+  // CHECK:      WhileStmt {{.*}}
+  // CHECK-NEXT: |-RecoveryExpr {{.*}} <col:10, col:18> '<dependent type>' contains-errors
+  // CHECK-NEXT: | `-UnresolvedLookupExpr {{.*}} <col:10>
+  while (invalid()) {}
+
+  // CHECK:      SwitchStmt {{.*}}
+  // CHECK-NEXT: |-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+  // CHECK-NEXT: | `-UnresolvedLookupExpr {{.*}} <col:10>
+  switch(invalid()) {
+    case 1:
+      break;
+  }
+  // FIXME: figure out why the type of ConditionalOperator is not int.
+  // CHECK:      ConditionalOperator {{.*}} '<dependent type>' contains-errors
+  // CHECK-NEXT: |-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+  // CHECK-NEXT: | `-UnresolvedLookupExpr {{.*}}
+  // CHECK-NEXT: |-IntegerLiteral {{.*}} 'int' 1
+  // CHECK-NEXT: `-IntegerLiteral {{.*}} 'int' 2
+  invalid() ? 1 : 2;
+}
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -18420,9 +18420,12 @@
     Cond = CheckSwitchCondition(Loc, SubExpr);
     break;
   }
-  if (Cond.isInvalid())
-    return ConditionError();
-
+  if (Cond.isInvalid()) {
+    Cond = CreateRecoveryExpr(SubExpr->getBeginLoc(), SubExpr->getEndLoc(),
+                              {SubExpr});
+    if (!Cond.get())
+      return ConditionError();
+  }
   // FIXME: FullExprArg doesn't have an invalid bit, so check nullness instead.
   FullExprArg FullExpr = MakeFullExpr(Cond.get(), Loc);
   if (!FullExpr.get())


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