Changeset 53449a4 for src/AST/Expr.cpp

Timestamp:

Dec 16, 2020, 4:01:57 PM (4 years ago)

Author:

Colby Alexander Parsons <caparsons@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

8ba363e, c8025a21

Parents:

b3c8496 (diff), 3e5dd913 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

File:

• src/AST/Expr.cpp (modified) (1 diff)

src/AST/Expr.cpp

@@ -206 +206 @@
         assert( aggregate->result );
 
-        // Deep copy on result type avoids mutation on transitively multiply referenced object.
-        //
-        // Example, adapted from parts of builtins and bootloader:
-        //
-        // forall(dtype T)
-        // struct __Destructor {
-        //   T * object;
-        //   void (*dtor)(T *);
-        // };
-        //
-        // forall(dtype S)
-        // void foo(__Destructor(S) &d) {
-        //   if (d.dtor) {  // here
-        //   }
-        // }
-        //
-        // Let e be the "d.dtor" guard espression, which is MemberExpr after resolve.  Let d be the
-        // declaration of member __Destructor.dtor (an ObjectDecl), as accessed via the top-level
-        // declaration of __Destructor.  Consider the types e.result and d.type.  In the old AST, one
-        // is a clone of the other.  Ordinary new-AST use would set them up as a multiply-referenced
-        // object.
-        //
-        // e.result: PointerType
-        // .base: FunctionType
-        // .params.front(): ObjectDecl, the anonymous parameter of type T*
-        // .type: PointerType
-        // .base: TypeInstType
-        // let x = that
-        // let y = similar, except start from d.type
-        //
-        // Consider two code lines down, genericSubstitution(...).apply(result).
-        //
-        // Applying this chosen-candidate's type substitution means modifying x, substituting
-        // S for T.  This mutation should affect x and not y.
-
-        result = deepCopy(mem->get_type());
+        result = mem->get_type();
 
         // substitute aggregate generic parameters into member type