Fix bug

backend_wat.go

@@ -134,6 +134,8 @@ func castPrimitiveWAT(from PrimitiveType, to PrimitiveType) (string, error) {
 		if getBits(to) < getBits(from) {
 			return getTypeCast(to), nil
 		}
+
+		return "", nil
 	}
 
 	if getBits(from) < 64 && getBits(to) == 64 {
@@ -334,7 +336,6 @@ func compileStatementWAT(stmt Statement, block *Block) (string, error) {
 		}
 
 		// TODO: upcast to return type for non-primitive types
-
 		return wat + "return\n", nil
 	case Statement_DeclareLocalVariable:
 		dlv := stmt.Value.(DeclareLocalVariableStatement)
@@ -347,7 +348,15 @@ func compileStatementWAT(stmt Statement, block *Block) (string, error) {
 			return "", err
 		}
 
-		// TODO: make sure to upcast to target type
+		if dlv.VariableType.Type == Type_Primitive {
+			castWAT, err := castPrimitiveWAT(dlv.Initializer.ValueType.Value.(PrimitiveType), dlv.VariableType.Value.(PrimitiveType))
+			if err != nil {
+				return "", err
+			}
+
+			wat += castWAT
+		}
+
 		return wat + "local.set $" + strconv.Itoa(block.Locals[dlv.Variable].Index) + "\n", nil
 	case Statement_If:
 		ifS := stmt.Value.(IfStatement)

example/add.lang

@@ -8,6 +8,7 @@ void a() {
 
 (u8, u8) doNothing(u8 a, u8 b) {
 	a = b;
+	u16 c = 1u8;
 	return a, b;
 }
 

example/test.lang

@@ -0,0 +1,3 @@
+void doNothing() {
+    u64 sus = 1u8;
+}