Method resolveType

bolt/expression/SwitchExpr.cpp:235–281

static

// static
TypePtr SwitchExpr::resolveType(const std::vector<TypePtr>& argTypes) {
  BOLT_CHECK_GT(
      argTypes.size(),
      1,
      "Switch statements expect at least 2 arguments, received {}",
      argTypes.size());
  // Type structure is [cond1Type, then1Type, cond2Type, then2Type, ...
  // elseType*]

  // Make sure all 'condition' expressions hae type BOOLEAN and all 'then' and
  // an optional 'else' clause have the same type.
  int numCases = argTypes.size() / 2;

  auto& expressionType = argTypes[1];

  for (auto i = 0; i < numCases; i++) {
    auto& conditionType = argTypes[i * 2];
    auto& thenType = argTypes[i * 2 + 1];

    BOLT_CHECK_EQ(
        conditionType->kind(),
        TypeKind::BOOLEAN,
        "Condition of  SWITCH statement is not bool");

    BOLT_CHECK(
        *thenType == *expressionType,
        "All then clauses of a SWITCH statement must have the same type. "
        "Expected {}, but got {}.",
        expressionType->toString(),
        thenType->toString());
  }

  bool hasElse = argTypes.size() % 2 == 1;

  if (hasElse) {
    auto& elseClauseType = argTypes.back();

    BOLT_CHECK(
        *elseClauseType == *expressionType,
        "Else clause of a SWITCH statement must have the same type as 'then' clauses. "
        "Expected {}, but got {}.",
        expressionType->toString(),
        elseClauseType->toString());
  }

  return expressionType;
}

TypePtr SwitchCallToSpecialForm::resolveType(
    const std::vector<TypePtr>& argTypes) {