Cleanup error handling for CallExpr

Call Expressions need to type check the argument passing but the type
system will return TyTy::Error nodes, it used to return nullptr about a
year ago. Returning error nodes are safer and more flexible for detailed
error handling and diagnostics.

Addresses: #539

2 files changed, 13 insertions, 9 deletions

diff --git a/gcc/rust/typecheck/rust-tyty.cc b/gcc/rust/typecheck/rust-tyty.cc
index 69fb8c4..dd33975 100644
--- a/gcc/rust/typecheck/rust-tyty.cc
+++ b/gcc/rust/typecheck/rust-tyty.cc
@@ -2352,14 +2352,14 @@ TypeCheckCallExpr::visit (ADTType &type)
     BaseType *field_tyty = field->get_field_type ();
 
     BaseType *arg = Resolver::TypeCheckExpr::Resolve (p, false);
-    if (arg == nullptr)
+    if (arg->get_kind () == TyTy::TypeKind::ERROR)
       {
 	rust_error_at (p->get_locus (), "failed to resolve argument type");
 	return false;
       }
 
     auto res = field_tyty->unify (arg);
-    if (res == nullptr)
+    if (res->get_kind () == TyTy::TypeKind::ERROR)
       {
 	return false;
       }
@@ -2407,7 +2407,7 @@ TypeCheckCallExpr::visit (FnType &type)
   size_t i = 0;
   call.iterate_params ([&] (HIR::Expr *param) mutable -> bool {
     auto argument_expr_tyty = Resolver::TypeCheckExpr::Resolve (param, false);
-    if (argument_expr_tyty == nullptr)
+    if (argument_expr_tyty->get_kind () == TyTy::TypeKind::ERROR)
       {
 	rust_error_at (param->get_locus (),
 		       "failed to resolve type for argument expr in CallExpr");
@@ -2421,7 +2421,7 @@ TypeCheckCallExpr::visit (FnType &type)
       {
 	auto fnparam = type.param_at (i);
 	resolved_argument_type = fnparam.second->unify (argument_expr_tyty);
-	if (resolved_argument_type == nullptr)
+	if (argument_expr_tyty->get_kind () == TyTy::TypeKind::ERROR)
 	  {
 	    rust_error_at (param->get_locus (),
 			   "Type Resolution failure on parameter");
@@ -2472,7 +2472,7 @@ TypeCheckCallExpr::visit (FnPtr &type)
   call.iterate_params ([&] (HIR::Expr *param) mutable -> bool {
     auto fnparam = type.param_at (i);
     auto argument_expr_tyty = Resolver::TypeCheckExpr::Resolve (param, false);
-    if (argument_expr_tyty == nullptr)
+    if (argument_expr_tyty->get_kind () == TyTy::TypeKind::ERROR)
       {
 	rust_error_at (param->get_locus (),
 		       "failed to resolve type for argument expr in CallExpr");
@@ -2480,7 +2480,7 @@ TypeCheckCallExpr::visit (FnPtr &type)
       }
 
     auto resolved_argument_type = fnparam->unify (argument_expr_tyty);
-    if (resolved_argument_type == nullptr)
+    if (argument_expr_tyty->get_kind () == TyTy::TypeKind::ERROR)
       {
 	rust_error_at (param->get_locus (),
 		       "Type Resolution failure on parameter");
@@ -2523,7 +2523,7 @@ TypeCheckMethodCallExpr::visit (FnType &type)
   call.iterate_params ([&] (HIR::Expr *param) mutable -> bool {
     auto fnparam = type.param_at (i);
     auto argument_expr_tyty = Resolver::TypeCheckExpr::Resolve (param, false);
-    if (argument_expr_tyty == nullptr)
+    if (argument_expr_tyty->get_kind () == TyTy::TypeKind::ERROR)
       {
 	rust_error_at (param->get_locus (),
 		       "failed to resolve type for argument expr in CallExpr");
@@ -2531,7 +2531,7 @@ TypeCheckMethodCallExpr::visit (FnType &type)
       }
 
     auto resolved_argument_type = fnparam.second->unify (argument_expr_tyty);
-    if (resolved_argument_type == nullptr)
+    if (argument_expr_tyty->get_kind () == TyTy::TypeKind::ERROR)
       {
 	rust_error_at (param->get_locus (),
 		       "Type Resolution failure on parameter");
diff --git a/gcc/testsuite/rust/compile/tuple_struct3.rs b/gcc/testsuite/rust/compile/tuple_struct3.rs
index c52a610..1af72a2 100644
--- a/gcc/testsuite/rust/compile/tuple_struct3.rs
+++ b/gcc/testsuite/rust/compile/tuple_struct3.rs
@@ -1,5 +1,9 @@
 struct Foo(i32, i32, bool);
 
 fn main() {
-    let c = Foo(1, 2f32, true); // { dg-error "expected .i32. got .f32." }
+    let c = Foo(1, 2f32, true);
+    // { dg-error "expected .i32. got .f32." "" { target *-*-* } .-1 }
+    // { dg-error "unexpected number of arguments 1 expected 3" "" { target *-*-* } .-2 }
+    // { dg-error "failed to lookup type to CallExpr" "" { target *-*-* } .-3 }
+    // { dg-error "failed to type resolve expression" "" { target *-*-* } .-4 }
 }