Merge #381

381: Fix crash on empty parameters to generic data type r=philberty a=philberty

When no parameters are passed to generic data types we cannot properly
infer the usage of the generic block.

This brings in a canonicalized check for `rustc --explain E0107`

Fixes #379

Co-authored-by: Philip Herron <philip.herron@embecosm.com>

7 files changed, 86 insertions, 54 deletions

diff --git a/gcc/rust/hir/tree/rust-hir-path.h b/gcc/rust/hir/tree/rust-hir-path.h
index d6f9fc0..262a04a 100644
--- a/gcc/rust/hir/tree/rust-hir-path.h
+++ b/gcc/rust/hir/tree/rust-hir-path.h
@@ -165,11 +165,11 @@ public:
   GenericArgs &operator= (GenericArgs &&other) = default;
 
   // Creates an empty GenericArgs (no arguments)
-  static GenericArgs create_empty ()
+  static GenericArgs create_empty (Location locus = Location ())
   {
     return GenericArgs (std::vector<Lifetime> (),
 			std::vector<std::unique_ptr<Type> > (),
-			std::vector<GenericArgsBinding> ());
+			std::vector<GenericArgsBinding> (), locus);
   }
 
   bool is_empty () const
diff --git a/gcc/rust/typecheck/rust-hir-type-check-toplevel.h b/gcc/rust/typecheck/rust-hir-type-check-toplevel.h
index 356faa6..8b23920 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-toplevel.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-toplevel.h
@@ -214,10 +214,7 @@ public:
     auto self
       = TypeCheckType::Resolve (impl_block.get_type ().get (), &substitutions);
     if (self == nullptr || self->get_kind () == TyTy::TypeKind::ERROR)
-      {
-	rust_error_at (impl_block.get_locus (), "failed to resolve impl type");
-	return;
-      }
+      return;
 
     for (auto &impl_item : impl_block.get_impl_items ())
       TypeCheckTopLevelImplItem::Resolve (impl_item.get (), self,
diff --git a/gcc/rust/typecheck/rust-hir-type-check-type.h b/gcc/rust/typecheck/rust-hir-type-check-type.h
index 6556947..5c21d5a 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-type.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-type.h
@@ -72,7 +72,7 @@ class TypeCheckResolveGenericArguments : public TypeCheckBase
 public:
   static HIR::GenericArgs resolve (HIR::TypePathSegment *segment)
   {
-    TypeCheckResolveGenericArguments resolver;
+    TypeCheckResolveGenericArguments resolver (segment->get_locus ());
     segment->accept_vis (resolver);
     return resolver.args;
   };
@@ -83,8 +83,8 @@ public:
   }
 
 private:
-  TypeCheckResolveGenericArguments ()
-    : TypeCheckBase (), args (HIR::GenericArgs::create_empty ())
+  TypeCheckResolveGenericArguments (Location locus)
+    : TypeCheckBase (), args (HIR::GenericArgs::create_empty (locus))
   {}
 
   HIR::GenericArgs args;
@@ -165,57 +165,57 @@ public:
 	return;
       }
 
-    // reverse lookup the hir node from ast node id
     HirId hir_lookup;
-    if (context->lookup_type_by_node_id (ref, &hir_lookup))
+    if (!context->lookup_type_by_node_id (ref, &hir_lookup))
       {
-	// we got an HIR node
-	if (context->lookup_type (hir_lookup, &translated))
-	  {
-	    translated = translated->clone ();
-	    auto ref = path.get_mappings ().get_hirid ();
-	    translated->set_ref (ref);
-
-	    HIR::TypePathSegment *final_seg = path.get_final_segment ();
-	    HIR::GenericArgs args
-	      = TypeCheckResolveGenericArguments::resolve (final_seg);
-
-	    bool path_declared_generic_arguments = !args.is_empty ();
-	    if (path_declared_generic_arguments)
-	      {
-		if (translated->has_subsititions_defined ())
-		  {
-		    translated
-		      = SubstMapper::Resolve (translated, path.get_locus (),
-					      &args);
-		    if (translated->get_kind () != TyTy::TypeKind::ERROR
-			&& mappings != nullptr)
-		      {
-			check_for_unconstrained (args.get_type_args ());
-		      }
-		  }
-		else
-		  {
-		    rust_error_at (
-		      path.get_locus (),
-		      "TypePath %s declares generic argument's but "
-		      "the type %s does not have any",
-		      path.as_string ().c_str (),
-		      translated->as_string ().c_str ());
-		  }
-	      }
-	    else if (translated->has_subsititions_defined ())
-	      {
-		translated
-		  = SubstMapper::InferSubst (translated, path.get_locus ());
-	      }
+	rust_error_at (path.get_locus (), "failed to lookup HIR node");
+	return;
+      }
+
+    TyTy::BaseType *lookup = nullptr;
+    if (!context->lookup_type (hir_lookup, &lookup))
+      {
+	rust_error_at (path.get_locus (), "failed to lookup HIR TyTy");
+	return;
+      }
+
+    TyTy::BaseType *path_type = lookup->clone ();
+    path_type->set_ref (path.get_mappings ().get_hirid ());
+
+    HIR::TypePathSegment *final_seg = path.get_final_segment ();
+    HIR::GenericArgs args
+      = TypeCheckResolveGenericArguments::resolve (final_seg);
+
+    bool is_big_self = final_seg->is_ident_only ()
+		       && (final_seg->as_string ().compare ("Self") == 0);
 
+    if (path_type->needs_generic_substitutions ())
+      {
+	if (is_big_self)
+	  {
+	    translated = path_type;
 	    return;
 	  }
-      }
 
-    rust_error_at (path.get_locus (), "failed to type-resolve TypePath: %s",
-		   path.as_string ().c_str ());
+	translated = SubstMapper::Resolve (path_type, path.get_locus (), &args);
+	if (translated->get_kind () != TyTy::TypeKind::ERROR
+	    && mappings != nullptr)
+	  {
+	    check_for_unconstrained (args.get_type_args ());
+	  }
+      }
+    else if (!args.is_empty ())
+      {
+	rust_error_at (path.get_locus (),
+		       "TypePath %s declares generic argument's but "
+		       "the type %s does not have any",
+		       path.as_string ().c_str (),
+		       translated->as_string ().c_str ());
+      }
+    else
+      {
+	translated = path_type;
+      }
   }
 
   void visit (HIR::ArrayType &type) override
diff --git a/gcc/rust/typecheck/rust-substitution-mapper.h b/gcc/rust/typecheck/rust-substitution-mapper.h
index bc20e4b..cd04b0e 100644
--- a/gcc/rust/typecheck/rust-substitution-mapper.h
+++ b/gcc/rust/typecheck/rust-substitution-mapper.h
@@ -57,6 +57,9 @@ public:
       {
 	TyTy::SubstitutionArgumentMappings mappings
 	  = type.get_mappings_from_generic_args (*generics);
+	if (mappings.is_error ())
+	  return;
+
 	concrete = type.handle_substitions (mappings);
       }
 
@@ -77,6 +80,9 @@ public:
       {
 	TyTy::SubstitutionArgumentMappings mappings
 	  = type.get_mappings_from_generic_args (*generics);
+	if (mappings.is_error ())
+	  return;
+
 	concrete = type.handle_substitions (mappings);
       }
 
diff --git a/gcc/testsuite/rust.test/xfail_compile/expected_type_args2.rs b/gcc/testsuite/rust.test/xfail_compile/expected_type_args2.rs
new file mode 100644
index 0000000..b92c48f
--- /dev/null
+++ b/gcc/testsuite/rust.test/xfail_compile/expected_type_args2.rs
@@ -0,0 +1,6 @@
+struct Foo<A>(A);
+
+fn main() {
+    let a: Foo = Foo::<i32>(123);
+    // { dg-error "Invalid number of generic arguments to generic type" "" { target { *-*-* } } .-1 }
+}
diff --git a/gcc/testsuite/rust.test/xfail_compile/expected_type_args3.rs b/gcc/testsuite/rust.test/xfail_compile/expected_type_args3.rs
new file mode 100644
index 0000000..4c164ff
--- /dev/null
+++ b/gcc/testsuite/rust.test/xfail_compile/expected_type_args3.rs
@@ -0,0 +1,8 @@
+struct Foo<A>(A);
+
+impl Foo {
+    // { dg-error "Invalid number of generic arguments to generic type" "" { target { *-*-* } } .-1 }
+    fn test() -> i32 {
+        123
+    }
+}
diff --git a/gcc/testsuite/rust.test/xfail_compile/generics8.rs b/gcc/testsuite/rust.test/xfail_compile/generics8.rs
new file mode 100644
index 0000000..70bad1a
--- /dev/null
+++ b/gcc/testsuite/rust.test/xfail_compile/generics8.rs
@@ -0,0 +1,15 @@
+struct Foo<A, B>(A, B);
+
+impl<T> Foo<i32, T> {
+    fn test(a: T) -> T { // { dg-error "duplicate definitions with name test" }
+        a
+    }
+}
+
+impl Foo<i32, f32> {
+    fn test() -> f32 { // { dg-error "duplicate definitions with name test" }
+        123f32
+    }
+}
+
+fn main() {}