HIR Resolve - Replace default types, with correct Self replacement

3 files changed, 39 insertions, 7 deletions

diff --git a/src/hir_conv/bind.cpp b/src/hir_conv/bind.cpp
index 553d3b27..2deaac9d 100644
--- a/src/hir_conv/bind.cpp
+++ b/src/hir_conv/bind.cpp
@@ -289,13 +289,14 @@ namespace {
                 )
             )
         }
-        static void fix_param_count(const Span& sp, const ::HIR::GenericPath& path, const ::HIR::GenericParams& param_defs,  ::HIR::PathParams& params) {
+        static void fix_param_count(const Span& sp, const ::HIR::GenericPath& path, const ::HIR::GenericParams& param_defs, ::HIR::PathParams& params, bool fill_infer=true, const ::HIR::TypeRef* self_ty=nullptr)
+        {
             if( params.m_types.size() == param_defs.m_types.size() ) {
                 // Nothing to do, all good
                 return ;
             }
 
-            if( params.m_types.size() == 0 ) {
+            if( params.m_types.size() == 0 && fill_infer ) {
                 for(const auto& typ : param_defs.m_types) {
                     (void)typ;
                     params.m_types.push_back( ::HIR::TypeRef() );
@@ -311,12 +312,36 @@ namespace {
                         ERROR(sp, E0000, "Omitted type parameter with no default in " << path);
                     }
                     else {
-                        // TODO: What if this contains a generic param? (is that valid? Self maybe, what about others?)
-                        params.m_types.push_back( typ.m_default.clone() );
+                        // Clone, replacing `self` if a replacement was provided.
+                        auto ty = clone_ty_with(sp, typ.m_default, [&](const auto& ty, auto& out){
+                            if(const auto* te = ty.m_data.opt_Generic() )
+                            {
+                                if( te->binding != GENERIC_Self || !self_ty )
+                                    TODO(sp, "Monomorphise in fix_param_count - encountered " << ty << " in " << typ.m_default);
+                                out = self_ty->clone();
+                                return true;
+                            }
+                            return false;
+                            });
+                        params.m_types.push_back( mv$(ty) );
                     }
                 }
             }
         }
+        void visit_params(::HIR::GenericParams& params)
+        {
+            static Span sp;
+            for(auto& bound : params.m_bounds)
+            {
+                if(auto* be = bound.opt_TraitBound())
+                {
+                    const auto& trait = m_crate.get_trait_by_path(sp, be->trait.m_path.m_path);
+                    fix_param_count(sp, be->trait.m_path, trait.m_params, be->trait.m_path.m_params, /*fill_infer=*/false, &be->type);
+                }
+            }
+
+            ::HIR::Visitor::visit_params(params);
+        }
         void visit_type(::HIR::TypeRef& ty) override
         {
             //TRACE_FUNCTION_F(ty);
diff --git a/src/hir_typeck/helpers.cpp b/src/hir_typeck/helpers.cpp
index 6665bcd1..eb8fef0a 100644
--- a/src/hir_typeck/helpers.cpp
+++ b/src/hir_typeck/helpers.cpp
@@ -2786,7 +2786,8 @@ bool TraitResolution::find_trait_impls_crate(const Span& sp,
     auto monomorph = [&](const auto& gt)->const ::HIR::TypeRef& {
             const auto& ge = gt.m_data.as_Generic();
             ASSERT_BUG(sp, ge.binding >> 8 != 2, "");
-            assert( ge.binding < impl_params.size() );
+            ASSERT_BUG(sp, ge.binding != GENERIC_Self, "Unexpected Self");
+            ASSERT_BUG(sp, ge.binding < impl_params.size(), "OOB param in impl - " << gt );
             if( !impl_params[ge.binding] ) {
                 //BUG(sp, "Param " << ge.binding << " for `impl" << impl.m_params.fmt_args() << " " << trait << impl.m_trait_args << " for " << impl.m_type << "` wasn't constrained");
                 return placeholders[ge.binding];
diff --git a/src/hir_typeck/static.cpp b/src/hir_typeck/static.cpp
index 83d287b9..53bca030 100644
--- a/src/hir_typeck/static.cpp
+++ b/src/hir_typeck/static.cpp
@@ -582,8 +582,14 @@ bool StaticTraitResolve::find_impl__check_crate_raw(
     // Callback that returns monomorpisation results
     auto cb_monomorph = [&](const auto& gt)->const ::HIR::TypeRef& {
             const auto& ge = gt.m_data.as_Generic();
-            ASSERT_BUG(sp, ge.binding >> 8 != 2, "");
-            assert( ge.binding < impl_params.size() );
+            if( ge.binding == GENERIC_Self ) {
+                // TODO: `impl_type` or `des_type`
+                DEBUG("[find_impl__check_crate_raw] Self - " << impl_type << " or " << des_type);
+                //TODO(sp, "[find_impl__check_crate_raw] Self - " << impl_type << " or " << des_type);
+                return impl_type;
+            }
+            ASSERT_BUG(sp, ge.binding >> 8 != 2, "[find_impl__check_crate_raw] Placeholder param seen - " << gt);
+            ASSERT_BUG(sp, ge.binding < impl_params.size(), "[find_impl__check_crate_raw] Binding out of range - " << gt);
             if( !impl_params[ge.binding] ) {
                 return placeholders[ge.binding];
             }