Changeset d0d5054

Timestamp:

Apr 12, 2018, 5:13:04 PM (6 years ago)

Author:

Rob Schluntz <rschlunt@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, with_gc

Children:

01963df

Parents:

8711c6c

git-author:

Rob Schluntz <rschlunt@…> (04/12/18 17:07:59)

git-committer:

Rob Schluntz <rschlunt@…> (04/12/18 17:13:04)

Message:

Recursively substitute type variables when applying a substitution

Location:

src/SynTree

Files:

• TypeSubstitution.cc (modified) (1 diff)
• TypeSubstitution.h (modified) (1 diff)

src/SynTree/TypeSubstitution.cc

@@ -149 +149 @@
                 return inst;
         } else {
-///         std::cerr << "found " << inst->get_name() << ", replacing with ";
-///         i->second->print( std::cerr );
-///         std::cerr << std::endl;
+                // cut off infinite loop for the case where a type is bound to itself.
+                // Note: this does not prevent cycles in the general case, so it may be necessary to do something more sophisticated here.
+                // TODO: investigate preventing type variables from being bound to themselves in the first place.
+                if ( TypeInstType * replacement = dynamic_cast< TypeInstType * >( i->second ) ) {
+                        if ( inst->name == replacement->name ) {
+                                return inst;
+                        }
+                }
+                // std::cerr << "found " << inst->name << ", replacing with " << i->second << std::endl;
                 subCount++;
                 Type * newtype = i->second->clone();
                 newtype->get_qualifiers() |= inst->get_qualifiers();
                 delete inst;
-                return newtype;
+                // Note: need to recursively apply substitution to the new type because normalize does not substitute bound vars, but bound vars must be substituted when not in freeOnly mode.
+                return newtype->acceptMutator( *visitor );
         } // if
 }

src/SynTree/TypeSubstitution.h

@@ -129 +129 @@
 
 // definitition must happen after PassVisitor is included so that WithGuards can be used
-struct TypeSubstitution::Substituter : public WithGuards {
+struct TypeSubstitution::Substituter : public WithGuards, public WithVisitorRef<Substituter> {
                 Substituter( TypeSubstitution & sub, bool freeOnly ) : sub( sub ), freeOnly( freeOnly ) {}