We need to monomorphize tuples as well as ADT's

When we have generic data types or types that can contain type parameters
we need to make sure to avoid duplicating record types and abusing
structural equality rules in GCC. We do this by looking for already
compiled types that the item is equal to so they refer to the canoncial
record type.

Fixes #415

3 files changed, 42 insertions, 5 deletions

diff --git a/gcc/rust/backend/rust-compile-context.h b/gcc/rust/backend/rust-compile-context.h
index 11e791c..bdc9eca 100644
--- a/gcc/rust/backend/rust-compile-context.h
+++ b/gcc/rust/backend/rust-compile-context.h
@@ -66,7 +66,7 @@ public:
   bool lookup_compiled_types (HirId id, ::Btype **type,
 			      const TyTy::BaseType *ref = nullptr)
   {
-    if (ref != nullptr && ref->has_subsititions_defined ())
+    if (ref != nullptr)
       {
 	for (auto it = mono.begin (); it != mono.end (); it++)
 	  {
@@ -393,7 +393,8 @@ public:
 	return;
       }
 
-    bool ok = ctx->lookup_compiled_types (type.get_ty_ref (), &translated);
+    bool ok
+      = ctx->lookup_compiled_types (type.get_ty_ref (), &translated, &type);
     if (ok)
       return;
 
@@ -402,8 +403,7 @@ public:
     for (size_t i = 0; i < type.num_fields (); i++)
       {
 	TyTy::BaseType *field = type.get_field (i);
-	Btype *compiled_field_ty
-	  = TyTyCompile::compile (ctx->get_backend (), field);
+	Btype *compiled_field_ty = TyTyResolveCompile::compile (ctx, field);
 
 	Backend::Btyped_identifier f (std::to_string (i), compiled_field_ty,
 				      ctx->get_mappings ()->lookup_location (
@@ -418,7 +418,7 @@ public:
 					   type.get_ty_ref ()));
 
     ctx->push_type (named_struct);
-    ctx->insert_compiled_type (type.get_ty_ref (), named_struct);
+    ctx->insert_compiled_type (type.get_ty_ref (), named_struct, &type);
     translated = named_struct;
   }
 
diff --git a/gcc/testsuite/rust.test/compile/generics26.rs b/gcc/testsuite/rust.test/compile/generics26.rs
new file mode 100644
index 0000000..522e16f
--- /dev/null
+++ b/gcc/testsuite/rust.test/compile/generics26.rs
@@ -0,0 +1,21 @@
+// github issue #415
+fn test<A, B>(a: A, b: B) -> (A, B) {
+    (a, b)
+}
+
+fn main() {
+    let a = test::<i32, i32>(123, 456);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+
+    let b = test::<f32, f32>(123f32, 456f32);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+
+    let c = test::<_, _>(123, 456f32);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+
+    let d = test(true, 1234);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+
+    let e = test((123, false), 123f32);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+}
diff --git a/gcc/testsuite/rust.test/compile/generics27.rs b/gcc/testsuite/rust.test/compile/generics27.rs
new file mode 100644
index 0000000..9871638
--- /dev/null
+++ b/gcc/testsuite/rust.test/compile/generics27.rs
@@ -0,0 +1,16 @@
+// github issue #415
+fn test<A>(a: &A) -> &A {
+    a
+}
+
+fn main() {
+    let a = 123;
+    let b = &a;
+    let c = test(b);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+
+    let a = 123f32;
+    let b = &a;
+    let c = test(b);
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+}