[Heavy] Fix if with continuations and set!; Fix append_rec error checking

Author: ricejasonf

heavy/lib/Builtins.cpp

@@ -645,10 +645,11 @@ Value append_rec(Context& C, Value List, Value Cdr) {
   C.setLoc(List);
   if (isa<Empty>(List))
     return Cdr;
-  else if (Pair* P = dyn_cast<Pair>(List))
-    return C.CreatePair(P->Car, append_rec(C, P->Cdr, Cdr));
-  else
-    return Value();
+  if (Pair* P = dyn_cast<Pair>(List)) {
+    if (Value V = append_rec(C, P->Cdr, Cdr))
+      return C.CreatePair(P->Car, V);
+  }
+  return Value();
 };
 }
 void append(Context& C, ValueRefs Args) {

heavy/lib/OpGen.cpp

@@ -877,25 +877,18 @@ mlir::Value OpGen::createIf(SourceLocation Loc, Value Cond, Value Then,
     TailPosScope TPS(*this);
     IsTailPos = true;
 
-    // Then
-    {
+    auto handleBranch = [&](heavy::Value Value, mlir::Block* Block) {
       LambdaScope LS(*this, IfContOp);
       mlir::OpBuilder::InsertionGuard IG(Builder);
-      Builder.setInsertionPointToStart(ThenBlock);
-      mlir::Value Result = Visit(Then);
-      if (ThenBlock->empty() || !isa<ApplyOp>(ThenBlock->back()))
+      Builder.setInsertionPointToStart(Block);
+      mlir::Value Result = Visit(Value);
+      Block = Builder.getBlock();
+      if (Block->empty() || !isa<ApplyOp>(Block->back()))
         create<ContOp>(Loc, Result);
-    }
+    };
 
-    // Else
-    {
-      LambdaScope LS(*this, IfContOp);
-      mlir::OpBuilder::InsertionGuard IG(Builder);
-      Builder.setInsertionPointToStart(ElseBlock);
-      mlir::Value Result = Visit(Else);
-      if (ElseBlock->empty() || !isa<ApplyOp>(ElseBlock->back()))
-        create<ContOp>(Loc, Result);
-    }
+    handleBranch(Then, ThenBlock);
+    handleBranch(Else, ElseBlock);
   }
 
   if (TailPos) return mlir::Value();

heavy/test/Evaluate/if.scm

@@ -66,6 +66,24 @@
   (write temp)))
 (newline)
 
+; CHECK-NEXT: 5
+((lambda ()
+  (define temp 42)
+  (if (eqv? temp 42)
+    (set! temp (+ 5))
+    (set! temp 6))
+  (write temp)))
+(newline)
+
+; CHECK-NEXT: 6
+((lambda ()
+  (define temp 42)
+  (if (eqv? temp 43)
+    (set! temp 5)
+    (set! temp (+ 5 1)))
+  (write temp)))
+(newline)
+
 ; CHECK-NEXT: foo
 (write
   (if (null? '()) 'return-foo 'return-bar))