[gcc/devel/rust/master] Constant folder now returns error_mark_node instead of nullptr

[gcc/devel/rust/master] Constant folder now returns error_mark_node instead of nullptr

[Thomas Schwinge]

https://gcc.gnu.org/g:f742bead5f4eb94908f188b99a3b261de0be9ca2

commit f742bead5f4eb94908f188b99a3b261de0be9ca2
Author: Nirmal Patel <npate012@gmail.com>
Date:   Sat Dec 11 14:05:06 2021 -0500

    Constant folder now returns error_mark_node instead of nullptr
    
    Removed nullptr checking on results from constant folder because when the
    result is already error_mark_node, we no longer need to check if the result
    is nullptr.
    
    Fixes #692
    
    Signed-off-by: Nirmal Patel <npate012@gmail.com>

Diff:
---
 gcc/rust/typecheck/rust-hir-const-fold.cc         | 2 --
 gcc/rust/typecheck/rust-hir-const-fold.h          | 9 +--------
 gcc/rust/typecheck/rust-hir-type-check-enumitem.h | 3 +--
 gcc/rust/typecheck/rust-hir-type-check.cc         | 2 --
 4 files changed, 2 insertions(+), 14 deletions(-)

diff --git a/gcc/rust/typecheck/rust-hir-const-fold.cc b/gcc/rust/typecheck/rust-hir-const-fold.cc
index 6acedd19b0f..1545c1a6efd 100644
--- a/gcc/rust/typecheck/rust-hir-const-fold.cc
+++ b/gcc/rust/typecheck/rust-hir-const-fold.cc
@@ -64,8 +64,6 @@ void
 ConstFoldItem::visit (HIR::ConstantItem &item)
 {
   auto folded_expr = ConstFoldExpr::fold (item.get_expr ());
-  if (folded_expr == nullptr)
-    return;
 
   folded = folded_expr;
 }
diff --git a/gcc/rust/typecheck/rust-hir-const-fold.h b/gcc/rust/typecheck/rust-hir-const-fold.h
index c965e25017c..d1f71277754 100644
--- a/gcc/rust/typecheck/rust-hir-const-fold.h
+++ b/gcc/rust/typecheck/rust-hir-const-fold.h
@@ -299,7 +299,7 @@ public:
     if (folder.ctx->get_backend ()->is_error_expression (folder.folded))
       {
 	rust_error_at (expr->get_locus (), "non const value");
-	return nullptr;
+	return folder.ctx->get_backend ()->error_expression ();
       }
 
     folder.ctx->insert_const (expr->get_mappings ().get_hirid (),
@@ -423,12 +423,7 @@ public:
   void visit (HIR::ArithmeticOrLogicalExpr &expr) override
   {
     auto lhs = ConstFoldExpr::fold (expr.get_lhs ());
-    if (lhs == nullptr)
-      return;
-
     auto rhs = ConstFoldExpr::fold (expr.get_rhs ());
-    if (rhs == nullptr)
-      return;
 
     auto op = expr.get_expr_type ();
     auto location = expr.get_locus ();
@@ -441,8 +436,6 @@ public:
   void visit (HIR::NegationExpr &expr) override
   {
     auto negated_expr = ConstFoldExpr::fold (expr.get_expr ().get ());
-    if (negated_expr == nullptr)
-      return;
 
     auto op = expr.get_expr_type ();
     auto location = expr.get_locus ();
diff --git a/gcc/rust/typecheck/rust-hir-type-check-enumitem.h b/gcc/rust/typecheck/rust-hir-type-check-enumitem.h
index e4dcaeb2326..4df7df6dd12 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-enumitem.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-enumitem.h
@@ -74,8 +74,7 @@ public:
     auto backend = rust_get_backend ();
     auto folded_discriminant
       = ConstFold::ConstFoldExpr::fold (discriminant.get ());
-    if (folded_discriminant == nullptr
-	|| backend->is_error_expression (folded_discriminant))
+    if (backend->is_error_expression (folded_discriminant))
       return;
 
     size_t specified_discriminant;
diff --git a/gcc/rust/typecheck/rust-hir-type-check.cc b/gcc/rust/typecheck/rust-hir-type-check.cc
index ca4842a1630..4596973c2c1 100644
--- a/gcc/rust/typecheck/rust-hir-type-check.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check.cc
@@ -151,8 +151,6 @@ TypeCheckType::visit (HIR::ArrayType &type)
     return;
 
   auto capacity = ConstFold::ConstFoldExpr::fold (type.get_size_expr ());
-  if (capacity == nullptr)
-    return;
 
   TyTy::BaseType *base = TypeCheckType::Resolve (type.get_element_type ());
   translated = new TyTy::ArrayType (type.get_mappings ().get_hirid (), capacity,