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Fix switch case control flow #27612

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Merged
ahejlsberg merged 4 commits into from
Oct 8, 2018
Merged

Fix switch case control flow #27612

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c80f532
Add missing check in getTypeAtSwitchClause
ahejlsberg Oct 8, 2018
cb47351
Remove duplicate code
ahejlsberg Oct 8, 2018
077bd1a
Add regression test
ahejlsberg Oct 8, 2018
7bdc361
Accept new baselines
ahejlsberg Oct 8, 2018
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1 change: 0 additions & 1 deletion src/compiler/binder.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1181,7 +1181,6 @@ namespace ts {
}
const preCaseLabel = createBranchLabel();
addAntecedent(preCaseLabel, createFlowSwitchClause(preSwitchCaseFlow!, node.parent, clauseStart, i + 1));
addAntecedent(preCaseLabel, createFlowSwitchClause(preSwitchCaseFlow!, node.parent, clauseStart, i + 1));
addAntecedent(preCaseLabel, fallthroughFlow);
currentFlow = finishFlowLabel(preCaseLabel);
const clause = clauses[i];
Expand Down
5 changes: 4 additions & 1 deletion src/compiler/checker.ts
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Expand Up @@ -14972,9 +14972,12 @@ namespace ts {
}

function getTypeAtSwitchClause(flow: FlowSwitchClause): FlowType {
const expr = flow.switchStatement.expression;
if (containsMatchingReferenceDiscriminant(reference, expr)) {
return declaredType;
}
const flowType = getTypeAtFlowNode(flow.antecedent);
let type = getTypeFromFlowType(flowType);
const expr = flow.switchStatement.expression;
if (isMatchingReference(reference, expr)) {
type = narrowTypeBySwitchOnDiscriminant(type, flow.switchStatement, flow.clauseStart, flow.clauseEnd);
}
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35 changes: 34 additions & 1 deletion tests/baselines/reference/discriminantPropertyCheck.errors.txt
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Expand Up @@ -73,4 +73,37 @@ tests/cases/compiler/discriminantPropertyCheck.ts(65,9): error TS2532: Object is
~~~~~
!!! error TS2532: Object is possibly 'undefined'.
}
}
}

// Repro from #27493

enum Types { Str = 1, Num = 2 }

type Instance = StrType | NumType;

interface StrType {
type: Types.Str;
value: string;
length: number;
}

interface NumType {
type: Types.Num;
value: number;
}

function func2(inst: Instance) {
while (true) {
switch (inst.type) {
case Types.Str: {
inst.value.length;
break;
}
case Types.Num: {
inst.value.toExponential;
break;
}
}
}
}

55 changes: 54 additions & 1 deletion tests/baselines/reference/discriminantPropertyCheck.js
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Expand Up @@ -65,7 +65,40 @@ function foo6(x: Item) {
if (x.foo !== undefined && x.qux) {
x.foo.length; // Error, intervening discriminant guard
}
}
}

// Repro from #27493

enum Types { Str = 1, Num = 2 }

type Instance = StrType | NumType;

interface StrType {
type: Types.Str;
value: string;
length: number;
}

interface NumType {
type: Types.Num;
value: number;
}

function func2(inst: Instance) {
while (true) {
switch (inst.type) {
case Types.Str: {
inst.value.length;
break;
}
case Types.Num: {
inst.value.toExponential;
break;
}
}
}
}


//// [discriminantPropertyCheck.js]
function goo1(x) {
Expand Down Expand Up @@ -108,3 +141,23 @@ function foo6(x) {
x.foo.length; // Error, intervening discriminant guard
}
}
// Repro from #27493
var Types;
(function (Types) {
Types[Types["Str"] = 1] = "Str";
Types[Types["Num"] = 2] = "Num";
})(Types || (Types = {}));
function func2(inst) {
while (true) {
switch (inst.type) {
case Types.Str: {
inst.value.length;
break;
}
case Types.Num: {
inst.value.toExponential;
break;
}
}
}
}
83 changes: 83 additions & 0 deletions tests/baselines/reference/discriminantPropertyCheck.symbols
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Expand Up @@ -228,3 +228,86 @@ function foo6(x: Item) {
>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
}
}

// Repro from #27493

enum Types { Str = 1, Num = 2 }
>Types : Symbol(Types, Decl(discriminantPropertyCheck.ts, 66, 1))
>Str : Symbol(Types.Str, Decl(discriminantPropertyCheck.ts, 70, 12))
>Num : Symbol(Types.Num, Decl(discriminantPropertyCheck.ts, 70, 21))

type Instance = StrType | NumType;
>Instance : Symbol(Instance, Decl(discriminantPropertyCheck.ts, 70, 31))
>StrType : Symbol(StrType, Decl(discriminantPropertyCheck.ts, 72, 34))
>NumType : Symbol(NumType, Decl(discriminantPropertyCheck.ts, 78, 1))

interface StrType {
>StrType : Symbol(StrType, Decl(discriminantPropertyCheck.ts, 72, 34))

type: Types.Str;
>type : Symbol(StrType.type, Decl(discriminantPropertyCheck.ts, 74, 19))
>Types : Symbol(Types, Decl(discriminantPropertyCheck.ts, 66, 1))
>Str : Symbol(Types.Str, Decl(discriminantPropertyCheck.ts, 70, 12))

value: string;
>value : Symbol(StrType.value, Decl(discriminantPropertyCheck.ts, 75, 20))

length: number;
>length : Symbol(StrType.length, Decl(discriminantPropertyCheck.ts, 76, 18))
}

interface NumType {
>NumType : Symbol(NumType, Decl(discriminantPropertyCheck.ts, 78, 1))

type: Types.Num;
>type : Symbol(NumType.type, Decl(discriminantPropertyCheck.ts, 80, 19))
>Types : Symbol(Types, Decl(discriminantPropertyCheck.ts, 66, 1))
>Num : Symbol(Types.Num, Decl(discriminantPropertyCheck.ts, 70, 21))

value: number;
>value : Symbol(NumType.value, Decl(discriminantPropertyCheck.ts, 81, 20))
}

function func2(inst: Instance) {
>func2 : Symbol(func2, Decl(discriminantPropertyCheck.ts, 83, 1))
>inst : Symbol(inst, Decl(discriminantPropertyCheck.ts, 85, 15))
>Instance : Symbol(Instance, Decl(discriminantPropertyCheck.ts, 70, 31))

while (true) {
switch (inst.type) {
>inst.type : Symbol(type, Decl(discriminantPropertyCheck.ts, 74, 19), Decl(discriminantPropertyCheck.ts, 80, 19))
>inst : Symbol(inst, Decl(discriminantPropertyCheck.ts, 85, 15))
>type : Symbol(type, Decl(discriminantPropertyCheck.ts, 74, 19), Decl(discriminantPropertyCheck.ts, 80, 19))

case Types.Str: {
>Types.Str : Symbol(Types.Str, Decl(discriminantPropertyCheck.ts, 70, 12))
>Types : Symbol(Types, Decl(discriminantPropertyCheck.ts, 66, 1))
>Str : Symbol(Types.Str, Decl(discriminantPropertyCheck.ts, 70, 12))

inst.value.length;
>inst.value.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
>inst.value : Symbol(StrType.value, Decl(discriminantPropertyCheck.ts, 75, 20))
>inst : Symbol(inst, Decl(discriminantPropertyCheck.ts, 85, 15))
>value : Symbol(StrType.value, Decl(discriminantPropertyCheck.ts, 75, 20))
>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))

break;
}
case Types.Num: {
>Types.Num : Symbol(Types.Num, Decl(discriminantPropertyCheck.ts, 70, 21))
>Types : Symbol(Types, Decl(discriminantPropertyCheck.ts, 66, 1))
>Num : Symbol(Types.Num, Decl(discriminantPropertyCheck.ts, 70, 21))

inst.value.toExponential;
>inst.value.toExponential : Symbol(Number.toExponential, Decl(lib.es5.d.ts, --, --))
>inst.value : Symbol(NumType.value, Decl(discriminantPropertyCheck.ts, 81, 20))
>inst : Symbol(inst, Decl(discriminantPropertyCheck.ts, 85, 15))
>value : Symbol(NumType.value, Decl(discriminantPropertyCheck.ts, 81, 20))
>toExponential : Symbol(Number.toExponential, Decl(lib.es5.d.ts, --, --))

break;
}
}
}
}

78 changes: 78 additions & 0 deletions tests/baselines/reference/discriminantPropertyCheck.types
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Expand Up @@ -232,3 +232,81 @@ function foo6(x: Item) {
>length : number
}
}

// Repro from #27493

enum Types { Str = 1, Num = 2 }
>Types : Types
>Str : Types.Str
>1 : 1
>Num : Types.Num
>2 : 2

type Instance = StrType | NumType;
>Instance : Instance

interface StrType {
type: Types.Str;
>type : Types.Str
>Types : any

value: string;
>value : string

length: number;
>length : number
}

interface NumType {
type: Types.Num;
>type : Types.Num
>Types : any

value: number;
>value : number
}

function func2(inst: Instance) {
>func2 : (inst: Instance) => void
>inst : Instance

while (true) {
>true : true

switch (inst.type) {
>inst.type : Types
>inst : Instance
>type : Types

case Types.Str: {
>Types.Str : Types.Str
>Types : typeof Types
>Str : Types.Str

inst.value.length;
>inst.value.length : number
>inst.value : string
>inst : StrType
>value : string
>length : number

break;
}
case Types.Num: {
>Types.Num : Types.Num
>Types : typeof Types
>Num : Types.Num

inst.value.toExponential;
>inst.value.toExponential : (fractionDigits?: number | undefined) => string
>inst.value : number
>inst : NumType
>value : number
>toExponential : (fractionDigits?: number | undefined) => string

break;
}
}
}
}

34 changes: 33 additions & 1 deletion tests/cases/compiler/discriminantPropertyCheck.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -66,4 +66,36 @@ function foo6(x: Item) {
if (x.foo !== undefined && x.qux) {
x.foo.length; // Error, intervening discriminant guard
}
}
}

// Repro from #27493

enum Types { Str = 1, Num = 2 }

type Instance = StrType | NumType;

interface StrType {
type: Types.Str;
value: string;
length: number;
}

interface NumType {
type: Types.Num;
value: number;
}

function func2(inst: Instance) {
while (true) {
switch (inst.type) {
case Types.Str: {
inst.value.length;
break;
}
case Types.Num: {
inst.value.toExponential;
break;
}
}
}
}