Changeset 30bf6bf for src

Timestamp:

Mar 26, 2025, 3:29:50 PM (6 months ago)

Author:

Andrew Beach <ajbeach@…>

Branches:

master

Children:

10c1770

Parents:

379b6ea

Message:

Change to instantiateGeneric, removing some unneeded output. It isn't much more complex but it is and could be reverted need be. Fixes #199.

File:

• src/GenPoly/InstantiateGeneric.cpp (modified) (4 diffs)

src/GenPoly/InstantiateGeneric.cpp

@@ -42 +42 @@
 
 using type_vector = ast::vector< ast::TypeExpr >;
+
+template<typename C, typename V>
+bool contains( C const & container, V const & value ) {
+        return std::any_of( container.begin(), container.end(),
+                        [value]( auto& element ){ return element == value; } );
+}
 
 /// Abstracts type equality for a list of parameter types.
@@ -423 +429 @@
 }
 
-struct GenericInstantiator final :
+class GenericInstantiator final :
                 public ast::WithCodeLocation,
                 public ast::WithConstTypeSubstitution,
@@ -444 +450 @@
         /// member from an instantiation.
         int memberIndex = -1;
+        /// The polymorphic types we are currently instantiating.
+        ast::vector<ast::Decl> instantiating;
+public:
 
         GenericInstantiator() :
@@ -597 +606 @@
                         );
 
-                        // Forward declare before recursion. (TODO: Only when needed, #199.)
+                        // Insert the declaration so it doesn't create it again,
                         insert( inst, typeSubs, newDecl );
-                        if ( AggrDecl const * forwardDecl = ast::asForward( newDecl ) ) {
-                                declsToAddBefore.push_back( forwardDecl );
-                        }
+                        // ... but mark this declaration as one we are working on.
+                        auto guard = makeFuncGuard(
+                                [this, newDecl](){ instantiating.push_back( newDecl ); },
+                                [this](){ instantiating.pop_back(); } );
                         // Recursively instantiate members:
                         concDecl = strict_dynamic_cast<AggrDecl const *>(
                                 newDecl->accept( *visitor ) );
-                        // Must occur before declaration is added so
-                        // that member instantiation appear first.
+
+                        // Produce the declaration after its members are instantiated.
                         declsToAddBefore.push_back( concDecl );
+                } else if ( contains( instantiating, concDecl ) ) {
+                        if ( AggrDecl const * forwardDecl = ast::asForward( concDecl ) ) {
+                                declsToAddBefore.push_back( forwardDecl );
+                        }
                 }
                 return new ast::SueInstType<AggrDecl>( concDecl, inst->qualifiers );