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Cache last isReachableFlowNode result + switch statement CFA fix

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This commit is contained in:
Anders Hejlsberg
2019-09-17 07:01:07 -07:00
parent 282a7aff6e
commit 8cbf69489c
1 changed files with 12 additions and 4 deletions
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src/compiler/checker.ts
+12 -4
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@@ -820,6 +820,8 @@ namespace ts {
let flowLoopCount = 0;
let sharedFlowCount = 0;
let flowAnalysisDisabled = false;
let lastFlowNode: FlowNode | undefined;
let lastFlowNodeReachable: boolean;
const emptyStringType = getLiteralType("");
const zeroType = getLiteralType(0);
@@ -16995,11 +16997,17 @@ namespace ts {
}
function isReachableFlowNode(flow: FlowNode) {
return isReachableFlowNodeWorker(flow, /*skipCacheCheck*/ false);
const result = isReachableFlowNodeWorker(flow, /*skipCacheCheck*/ false);
lastFlowNode = flow;
lastFlowNodeReachable = result;
return result;
}
function isReachableFlowNodeWorker(flow: FlowNode, noCacheCheck: boolean): boolean {
while (true) {
if (flow === lastFlowNode) {
return lastFlowNodeReachable;
}
const flags = flow.flags;
if (flags & FlowFlags.Shared) {
if (!noCacheCheck) {
@@ -17329,9 +17337,6 @@ namespace ts {
}
function getTypeAtSwitchClause(flow: FlowSwitchClause): FlowType {
if (flow.clauseStart === flow.clauseEnd && isExhaustiveSwitchStatement(flow.switchStatement)) {
return neverType;
}
const expr = flow.switchStatement.expression;
const flowType = getTypeAtFlowNode(flow.antecedent);
let type = getTypeFromFlowType(flowType);
@@ -17350,6 +17355,9 @@ namespace ts {
else if (containsMatchingReferenceDiscriminant(reference, expr)) {
type = declaredType;
}
else if (flow.clauseStart === flow.clauseEnd && isExhaustiveSwitchStatement(flow.switchStatement)) {
return unreachableNeverType;
}
return createFlowType(type, isIncomplete(flowType));
}