public KotlinTypeInfo visitWhileExpression(
KtWhileExpression expression,
ExpressionTypingContext contextWithExpectedType,
boolean isStatement) {
if (!isStatement)
return components.dataFlowAnalyzer.illegalStatementType(
expression, contextWithExpectedType, facade);
ExpressionTypingContext context =
contextWithExpectedType
.replaceExpectedType(NO_EXPECTED_TYPE)
.replaceContextDependency(INDEPENDENT);
// Preliminary analysis
PreliminaryLoopVisitor loopVisitor = PreliminaryLoopVisitor.visitLoop(expression);
context =
context.replaceDataFlowInfo(
loopVisitor.clearDataFlowInfoForAssignedLocalVariables(context.dataFlowInfo));
KtExpression condition = expression.getCondition();
// Extract data flow info from condition itself without taking value into account
DataFlowInfo dataFlowInfo = checkCondition(context.scope, condition, context);
KtExpression body = expression.getBody();
KotlinTypeInfo bodyTypeInfo;
DataFlowInfo conditionInfo =
components
.dataFlowAnalyzer
.extractDataFlowInfoFromCondition(condition, true, context)
.and(dataFlowInfo);
if (body != null) {
LexicalWritableScope scopeToExtend =
newWritableScopeImpl(context, "Scope extended in while's condition");
bodyTypeInfo =
components.expressionTypingServices.getBlockReturnedTypeWithWritableScope(
scopeToExtend,
Collections.singletonList(body),
CoercionStrategy.NO_COERCION,
context.replaceDataFlowInfo(conditionInfo));
} else {
bodyTypeInfo = TypeInfoFactoryKt.noTypeInfo(conditionInfo);
}
// Condition is false at this point only if there is no jumps outside
if (!containsJumpOutOfLoop(expression, context)) {
dataFlowInfo =
components
.dataFlowAnalyzer
.extractDataFlowInfoFromCondition(condition, false, context)
.and(dataFlowInfo);
}
// Special case: while (true)
// In this case we must record data flow information at the nearest break / continue and
// .and it with entrance data flow information, because while body until break is executed at
// least once in this case
// See KT-6284
if (body != null && KtPsiUtil.isTrueConstant(condition)) {
// We should take data flow info from the first jump point,
// but without affecting changing variables
dataFlowInfo =
dataFlowInfo.and(
loopVisitor.clearDataFlowInfoForAssignedLocalVariables(
bodyTypeInfo.getJumpFlowInfo()));
}
return components
.dataFlowAnalyzer
.checkType(
bodyTypeInfo.replaceType(components.builtIns.getUnitType()),
expression,
contextWithExpectedType)
.replaceDataFlowInfo(dataFlowInfo);
}
