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navya9singhnavya9singh
authoredSep 26, 2022
Merge pull request #49912 from microsoft/fix/47508
fix(47508): noUncheckedIndexedAccess with enums Type narrowed
·
v5.8.2v4.9-rc
2 parents 5a10f46 + 80ae43d commit bc9cbbe

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5 files changed

+274
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5 files changed

+274
-1
lines changed
 

‎src/compiler/checker.ts

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Original file line numberDiff line numberDiff line change
@@ -15814,7 +15814,18 @@ namespace ts {
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return accessFlags & AccessFlags.IncludeUndefined ? getUnionType([indexInfo.type, undefinedType]) : indexInfo.type;
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}
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errorIfWritingToReadonlyIndex(indexInfo);
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return accessFlags & AccessFlags.IncludeUndefined ? getUnionType([indexInfo.type, undefinedType]) : indexInfo.type;
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// When accessing an enum object with its own type,
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// e.g. E[E.A] for enum E { A }, undefined shouldn't
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// be included in the result type
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if ((accessFlags & AccessFlags.IncludeUndefined) &&
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!(objectType.symbol &&
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objectType.symbol.flags & (SymbolFlags.RegularEnum | SymbolFlags.ConstEnum) &&
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(indexType.symbol &&
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indexType.flags & TypeFlags.EnumLiteral &&
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getParentOfSymbol(indexType.symbol) === objectType.symbol))) {
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return getUnionType([indexInfo.type, undefinedType]);
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}
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return indexInfo.type;
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}
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if (indexType.flags & TypeFlags.Never) {
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return neverType;

‎tests/baselines/reference/noUncheckedIndexAccess.js

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@@ -0,0 +1,58 @@
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//// [noUncheckedIndexAccess.ts]
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enum Meat {
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Sausage,
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Bacon
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}
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const sausage = Meat.Sausage
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const valueSausage = Meat[sausage]
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const bacon = Meat.Bacon
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const valueBacon = Meat[bacon]
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const union: Meat.Bacon | Meat.Sausage = Meat.Bacon
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const valueUnion = Meat[union]
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//Avoiding a false positive
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const value = Meat[0]
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const valueUndefined = "testing"
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const value2 = Meat[valueUndefined]
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enum A {
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a, b, c
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}
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enum B {
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x, y, z
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}
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const value3 = A[B.x];
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//// [noUncheckedIndexAccess.js]
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var Meat;
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(function (Meat) {
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Meat[Meat["Sausage"] = 0] = "Sausage";
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Meat[Meat["Bacon"] = 1] = "Bacon";
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})(Meat || (Meat = {}));
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var sausage = Meat.Sausage;
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var valueSausage = Meat[sausage];
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var bacon = Meat.Bacon;
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var valueBacon = Meat[bacon];
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var union = Meat.Bacon;
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var valueUnion = Meat[union];
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//Avoiding a false positive
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var value = Meat[0];
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var valueUndefined = "testing";
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var value2 = Meat[valueUndefined];
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var A;
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(function (A) {
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A[A["a"] = 0] = "a";
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A[A["b"] = 1] = "b";
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A[A["c"] = 2] = "c";
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})(A || (A = {}));
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var B;
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(function (B) {
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B[B["x"] = 0] = "x";
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B[B["y"] = 1] = "y";
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B[B["z"] = 2] = "z";
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})(B || (B = {}));
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var value3 = A[B.x];

‎tests/baselines/reference/noUncheckedIndexAccess.symbols

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@@ -0,0 +1,84 @@
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=== tests/cases/compiler/noUncheckedIndexAccess.ts ===
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enum Meat {
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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Sausage,
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>Sausage : Symbol(Meat.Sausage, Decl(noUncheckedIndexAccess.ts, 0, 11))
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Bacon
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>Bacon : Symbol(Meat.Bacon, Decl(noUncheckedIndexAccess.ts, 1, 12))
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}
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const sausage = Meat.Sausage
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>sausage : Symbol(sausage, Decl(noUncheckedIndexAccess.ts, 4, 7))
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>Meat.Sausage : Symbol(Meat.Sausage, Decl(noUncheckedIndexAccess.ts, 0, 11))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>Sausage : Symbol(Meat.Sausage, Decl(noUncheckedIndexAccess.ts, 0, 11))
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const valueSausage = Meat[sausage]
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>valueSausage : Symbol(valueSausage, Decl(noUncheckedIndexAccess.ts, 5, 7))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>sausage : Symbol(sausage, Decl(noUncheckedIndexAccess.ts, 4, 7))
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const bacon = Meat.Bacon
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>bacon : Symbol(bacon, Decl(noUncheckedIndexAccess.ts, 7, 7))
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>Meat.Bacon : Symbol(Meat.Bacon, Decl(noUncheckedIndexAccess.ts, 1, 12))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>Bacon : Symbol(Meat.Bacon, Decl(noUncheckedIndexAccess.ts, 1, 12))
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const valueBacon = Meat[bacon]
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>valueBacon : Symbol(valueBacon, Decl(noUncheckedIndexAccess.ts, 8, 7))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>bacon : Symbol(bacon, Decl(noUncheckedIndexAccess.ts, 7, 7))
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const union: Meat.Bacon | Meat.Sausage = Meat.Bacon
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>union : Symbol(union, Decl(noUncheckedIndexAccess.ts, 10, 7))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>Bacon : Symbol(Meat.Bacon, Decl(noUncheckedIndexAccess.ts, 1, 12))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>Sausage : Symbol(Meat.Sausage, Decl(noUncheckedIndexAccess.ts, 0, 11))
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>Meat.Bacon : Symbol(Meat.Bacon, Decl(noUncheckedIndexAccess.ts, 1, 12))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>Bacon : Symbol(Meat.Bacon, Decl(noUncheckedIndexAccess.ts, 1, 12))
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const valueUnion = Meat[union]
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>valueUnion : Symbol(valueUnion, Decl(noUncheckedIndexAccess.ts, 11, 7))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>union : Symbol(union, Decl(noUncheckedIndexAccess.ts, 10, 7))
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//Avoiding a false positive
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const value = Meat[0]
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>value : Symbol(value, Decl(noUncheckedIndexAccess.ts, 14, 7))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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const valueUndefined = "testing"
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>valueUndefined : Symbol(valueUndefined, Decl(noUncheckedIndexAccess.ts, 16, 7))
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const value2 = Meat[valueUndefined]
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>value2 : Symbol(value2, Decl(noUncheckedIndexAccess.ts, 17, 7))
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>Meat : Symbol(Meat, Decl(noUncheckedIndexAccess.ts, 0, 0))
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>valueUndefined : Symbol(valueUndefined, Decl(noUncheckedIndexAccess.ts, 16, 7))
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enum A {
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>A : Symbol(A, Decl(noUncheckedIndexAccess.ts, 17, 37))
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a, b, c
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>a : Symbol(A.a, Decl(noUncheckedIndexAccess.ts, 19, 10))
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>b : Symbol(A.b, Decl(noUncheckedIndexAccess.ts, 20, 6))
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>c : Symbol(A.c, Decl(noUncheckedIndexAccess.ts, 20, 9))
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}
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enum B {
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>B : Symbol(B, Decl(noUncheckedIndexAccess.ts, 21, 3))
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x, y, z
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>x : Symbol(B.x, Decl(noUncheckedIndexAccess.ts, 22, 10))
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>y : Symbol(B.y, Decl(noUncheckedIndexAccess.ts, 23, 6))
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>z : Symbol(B.z, Decl(noUncheckedIndexAccess.ts, 23, 9))
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}
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const value3 = A[B.x];
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>value3 : Symbol(value3, Decl(noUncheckedIndexAccess.ts, 26, 7))
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>A : Symbol(A, Decl(noUncheckedIndexAccess.ts, 17, 37))
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>B.x : Symbol(B.x, Decl(noUncheckedIndexAccess.ts, 22, 10))
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>B : Symbol(B, Decl(noUncheckedIndexAccess.ts, 21, 3))
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>x : Symbol(B.x, Decl(noUncheckedIndexAccess.ts, 22, 10))
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‎tests/baselines/reference/noUncheckedIndexAccess.types

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@@ -0,0 +1,90 @@
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=== tests/cases/compiler/noUncheckedIndexAccess.ts ===
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enum Meat {
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>Meat : Meat
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Sausage,
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>Sausage : Meat.Sausage
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Bacon
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>Bacon : Meat.Bacon
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}
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const sausage = Meat.Sausage
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>sausage : Meat.Sausage
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>Meat.Sausage : Meat.Sausage
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>Meat : typeof Meat
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>Sausage : Meat.Sausage
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const valueSausage = Meat[sausage]
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>valueSausage : string
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>Meat[sausage] : string
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>Meat : typeof Meat
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>sausage : Meat.Sausage
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const bacon = Meat.Bacon
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>bacon : Meat.Bacon
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>Meat.Bacon : Meat.Bacon
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>Meat : typeof Meat
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>Bacon : Meat.Bacon
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const valueBacon = Meat[bacon]
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>valueBacon : string
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>Meat[bacon] : string
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>Meat : typeof Meat
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>bacon : Meat.Bacon
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const union: Meat.Bacon | Meat.Sausage = Meat.Bacon
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>union : Meat
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>Meat : any
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>Meat : any
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>Meat.Bacon : Meat.Bacon
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>Meat : typeof Meat
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>Bacon : Meat.Bacon
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const valueUnion = Meat[union]
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>valueUnion : string
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>Meat[union] : string
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>Meat : typeof Meat
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>union : Meat.Bacon
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//Avoiding a false positive
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const value = Meat[0]
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>value : string | undefined
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>Meat[0] : string | undefined
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>Meat : typeof Meat
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>0 : 0
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const valueUndefined = "testing"
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>valueUndefined : "testing"
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>"testing" : "testing"
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const value2 = Meat[valueUndefined]
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>value2 : error
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>Meat[valueUndefined] : error
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>Meat : typeof Meat
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>valueUndefined : "testing"
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enum A {
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>A : A
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a, b, c
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>a : A.a
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>b : A.b
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>c : A.c
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}
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enum B {
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>B : B
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x, y, z
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>x : B.x
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>y : B.y
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>z : B.z
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}
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const value3 = A[B.x];
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>value3 : string | undefined
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>A[B.x] : string | undefined
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>A : typeof A
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>B.x : B.x
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>B : typeof B
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>x : B.x
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‎tests/cases/compiler/noUncheckedIndexAccess.ts

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//@noUncheckedIndexedAccess: true
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//@strictNullChecks: true
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enum Meat {
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Sausage,
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Bacon
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}
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const sausage = Meat.Sausage
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const valueSausage = Meat[sausage]
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const bacon = Meat.Bacon
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const valueBacon = Meat[bacon]
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const union: Meat.Bacon | Meat.Sausage = Meat.Bacon
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const valueUnion = Meat[union]
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//Avoiding a false positive
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const value = Meat[0]
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20+
const valueUndefined = "testing"
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const value2 = Meat[valueUndefined]
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enum A {
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a, b, c
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}
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enum B {
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x, y, z
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}
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const value3 = A[B.x];

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