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Fix switch statement exhaustiveness checking #34840

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Merged
merged 3 commits into from
Nov 5, 2019
Merged

Fix switch statement exhaustiveness checking #34840

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977841f
Don't optimize away CFA nodes representing missing default clauses
ahejlsberg Oct 30, 2019
a4fbe4a
Add regression test
ahejlsberg Oct 30, 2019
576e5f5
Accept new baselines
ahejlsberg Oct 30, 2019
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6 changes: 2 additions & 4 deletions src/compiler/binder.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -965,9 +965,6 @@ namespace ts {
}

function createFlowSwitchClause(antecedent: FlowNode, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number): FlowNode {
if (!isNarrowingExpression(switchStatement.expression)) {
return antecedent;
}
setFlowNodeReferenced(antecedent);
return flowNodeCreated({ flags: FlowFlags.SwitchClause, antecedent, switchStatement, clauseStart, clauseEnd });
}
Expand Down Expand Up @@ -1323,6 +1320,7 @@ namespace ts {
const savedSubtreeTransformFlags = subtreeTransformFlags;
subtreeTransformFlags = 0;
const clauses = node.clauses;
const isNarrowingSwitch = isNarrowingExpression(node.parent.expression);
let fallthroughFlow = unreachableFlow;
for (let i = 0; i < clauses.length; i++) {
const clauseStart = i;
Expand All @@ -1331,7 +1329,7 @@ namespace ts {
i++;
}
const preCaseLabel = createBranchLabel();
addAntecedent(preCaseLabel, createFlowSwitchClause(preSwitchCaseFlow!, node.parent, clauseStart, i + 1));
addAntecedent(preCaseLabel, isNarrowingSwitch ? createFlowSwitchClause(preSwitchCaseFlow!, node.parent, clauseStart, i + 1) : preSwitchCaseFlow!);
addAntecedent(preCaseLabel, fallthroughFlow);
currentFlow = finishFlowLabel(preCaseLabel);
const clause = clauses[i];
Expand Down
13 changes: 13 additions & 0 deletions tests/baselines/reference/exhaustiveSwitchStatements1.errors.txt
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Expand Up @@ -199,4 +199,17 @@ tests/cases/conformance/controlFlow/exhaustiveSwitchStatements1.ts(7,9): error T
}
return x;
}

// Repro from #34661

enum Animal { DOG, CAT }

declare const zoo: { animal: Animal } | undefined;

function expression(): Animal {
switch (zoo?.animal ?? Animal.DOG) {
case Animal.DOG: return Animal.DOG
case Animal.CAT: return Animal.CAT
}
}

34 changes: 34 additions & 0 deletions tests/baselines/reference/exhaustiveSwitchStatements1.js
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Expand Up @@ -194,6 +194,19 @@ function test4(value: 1 | 2) {
}
return x;
}

// Repro from #34661

enum Animal { DOG, CAT }

declare const zoo: { animal: Animal } | undefined;

function expression(): Animal {
switch (zoo?.animal ?? Animal.DOG) {
case Animal.DOG: return Animal.DOG
case Animal.CAT: return Animal.CAT
}
}


//// [exhaustiveSwitchStatements1.js]
Expand Down Expand Up @@ -379,6 +392,19 @@ function test4(value) {
}
return x;
}
// Repro from #34661
var Animal;
(function (Animal) {
Animal[Animal["DOG"] = 0] = "DOG";
Animal[Animal["CAT"] = 1] = "CAT";
})(Animal || (Animal = {}));
function expression() {
var _a, _b;
switch ((_b = (_a = zoo) === null || _a === void 0 ? void 0 : _a.animal, (_b !== null && _b !== void 0 ? _b : Animal.DOG))) {
case Animal.DOG: return Animal.DOG;
case Animal.CAT: return Animal.CAT;
}
}


//// [exhaustiveSwitchStatements1.d.ts]
Expand Down Expand Up @@ -435,3 +461,11 @@ declare type Shape2 = Square2 | Circle2;
declare function withDefault(s1: Shape2, s2: Shape2): string;
declare function withoutDefault(s1: Shape2, s2: Shape2): string;
declare function test4(value: 1 | 2): string;
declare enum Animal {
DOG = 0,
CAT = 1
}
declare const zoo: {
animal: Animal;
} | undefined;
declare function expression(): Animal;
42 changes: 42 additions & 0 deletions tests/baselines/reference/exhaustiveSwitchStatements1.symbols
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Expand Up @@ -501,3 +501,45 @@ function test4(value: 1 | 2) {
>x : Symbol(x, Decl(exhaustiveSwitchStatements1.ts, 188, 7))
}

// Repro from #34661

enum Animal { DOG, CAT }
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))
>DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))
>CAT : Symbol(Animal.CAT, Decl(exhaustiveSwitchStatements1.ts, 198, 18))

declare const zoo: { animal: Animal } | undefined;
>zoo : Symbol(zoo, Decl(exhaustiveSwitchStatements1.ts, 200, 13))
>animal : Symbol(animal, Decl(exhaustiveSwitchStatements1.ts, 200, 20))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))

function expression(): Animal {
>expression : Symbol(expression, Decl(exhaustiveSwitchStatements1.ts, 200, 50))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))

switch (zoo?.animal ?? Animal.DOG) {
>zoo?.animal : Symbol(animal, Decl(exhaustiveSwitchStatements1.ts, 200, 20))
>zoo : Symbol(zoo, Decl(exhaustiveSwitchStatements1.ts, 200, 13))
>animal : Symbol(animal, Decl(exhaustiveSwitchStatements1.ts, 200, 20))
>Animal.DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))
>DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))

case Animal.DOG: return Animal.DOG
>Animal.DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))
>DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))
>Animal.DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))
>DOG : Symbol(Animal.DOG, Decl(exhaustiveSwitchStatements1.ts, 198, 13))

case Animal.CAT: return Animal.CAT
>Animal.CAT : Symbol(Animal.CAT, Decl(exhaustiveSwitchStatements1.ts, 198, 18))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))
>CAT : Symbol(Animal.CAT, Decl(exhaustiveSwitchStatements1.ts, 198, 18))
>Animal.CAT : Symbol(Animal.CAT, Decl(exhaustiveSwitchStatements1.ts, 198, 18))
>Animal : Symbol(Animal, Decl(exhaustiveSwitchStatements1.ts, 194, 1))
>CAT : Symbol(Animal.CAT, Decl(exhaustiveSwitchStatements1.ts, 198, 18))
}
}

41 changes: 41 additions & 0 deletions tests/baselines/reference/exhaustiveSwitchStatements1.types
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Expand Up @@ -593,3 +593,44 @@ function test4(value: 1 | 2) {
>x : string
}

// Repro from #34661

enum Animal { DOG, CAT }
>Animal : Animal
>DOG : Animal.DOG
>CAT : Animal.CAT

declare const zoo: { animal: Animal } | undefined;
>zoo : { animal: Animal; } | undefined
>animal : Animal

function expression(): Animal {
>expression : () => Animal

switch (zoo?.animal ?? Animal.DOG) {
>zoo?.animal ?? Animal.DOG : Animal
>zoo?.animal : Animal | undefined
>zoo : { animal: Animal; } | undefined
>animal : Animal | undefined
>Animal.DOG : Animal.DOG
>Animal : typeof Animal
>DOG : Animal.DOG

case Animal.DOG: return Animal.DOG
>Animal.DOG : Animal.DOG
>Animal : typeof Animal
>DOG : Animal.DOG
>Animal.DOG : Animal.DOG
>Animal : typeof Animal
>DOG : Animal.DOG

case Animal.CAT: return Animal.CAT
>Animal.CAT : Animal.CAT
>Animal : typeof Animal
>CAT : Animal.CAT
>Animal.CAT : Animal.CAT
>Animal : typeof Animal
>CAT : Animal.CAT
}
}

13 changes: 13 additions & 0 deletions tests/cases/conformance/controlFlow/exhaustiveSwitchStatements1.ts
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Expand Up @@ -197,3 +197,16 @@ function test4(value: 1 | 2) {
}
return x;
}

// Repro from #34661

enum Animal { DOG, CAT }

declare const zoo: { animal: Animal } | undefined;

function expression(): Animal {
switch (zoo?.animal ?? Animal.DOG) {
case Animal.DOG: return Animal.DOG
case Animal.CAT: return Animal.CAT
}
}