private static TypeDesc ResolveType(IfInstr ifinstr, Environment env, CodePosition position)
{
TypeDesc conditionType = ResolveType(ifinstr.Condition, env, ifinstr.Condition.Position);
ExprNode mainBranchLast;
ExprNode elseBranchLast;
TypeDesc mainBranchType;
TypeDesc elseBranchType;
if (!(conditionType is BoolType))
{
throw new TypecheckerError(
new MismatchedTypes(new BoolType(), conditionType),
ifinstr.Condition.Position
);
}
RegularChecker mainChecker = new RegularChecker(ifinstr.MainBranch, env);
RegularChecker elseChecker = new RegularChecker(ifinstr.ElseBranch, env);
mainChecker.Typecheck();
elseChecker.Typecheck();
try
{
mainBranchLast = Utils.GetBlockLast(ifinstr.MainBranch);
} catch (ArgumentException)
{
mainBranchLast = new ExprNode(new NullExpr(), ifinstr.Condition.Position);
}
try
{
elseBranchLast = Utils.GetBlockLast(ifinstr.ElseBranch);
} catch (ArgumentException)
{
elseBranchLast = new ExprNode(new NullExpr(), ifinstr.Condition.Position);
}
mainBranchType = ResolveType(mainBranchLast, env, position);
elseBranchType = ResolveType(elseBranchLast, env, position);
if (mainBranchType.GetType() != elseBranchType.GetType())
{
throw new TypecheckerError(
new MismatchedTypes(mainBranchType, elseBranchType),
position
);
}
return(mainBranchType);
}
public void Typecheck()
{
foreach (InstrNode node in block.Instructions)
{
Instr instruction = node.Value;
if (instruction is VarDecl)
{
RegularChecker.CheckVarDecl(node, ref env);
}
if (instruction is ClassDecl)
{
ClassDecl decl = (ClassDecl)instruction;
env.AddEntry(decl.Name, new Class(decl.Typevars.Sequence), node.Position);
}
}
}
