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Merged
merged 2 commits into from
Jun 8, 2016
Merged

Improve typing of && operator with --strictNullChecks #8949

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bcc9220
Improve typing of && operator with --strictNullChecks
ahejlsberg Jun 3, 2016
13698a9
Add test
ahejlsberg Jun 3, 2016
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50 changes: 22 additions & 28 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2844,7 +2844,7 @@ namespace ts {
}
// In strict null checking mode, if a default value of a non-undefined type is specified, remove
// undefined from the final type.
if (strictNullChecks && declaration.initializer && !(getNullableKind(checkExpressionCached(declaration.initializer)) & TypeFlags.Undefined)) {
if (strictNullChecks && declaration.initializer && !(getCombinedTypeFlags(checkExpressionCached(declaration.initializer)) & TypeFlags.Undefined)) {
type = getTypeWithFacts(type, TypeFacts.NEUndefined);
}
return type;
Expand Down Expand Up @@ -2887,7 +2887,7 @@ namespace ts {
}

function addOptionality(type: Type, optional: boolean): Type {
return strictNullChecks && optional ? addNullableKind(type, TypeFlags.Undefined) : type;
return strictNullChecks && optional ? addTypeKind(type, TypeFlags.Undefined) : type;
}

// Return the inferred type for a variable, parameter, or property declaration
Expand Down Expand Up @@ -3222,7 +3222,7 @@ namespace ts {
if (!links.type) {
const type = createObjectType(TypeFlags.Anonymous, symbol);
links.type = strictNullChecks && symbol.flags & SymbolFlags.Optional ?
addNullableKind(type, TypeFlags.Undefined) : type;
addTypeKind(type, TypeFlags.Undefined) : type;
}
return links.type;
}
Expand Down Expand Up @@ -6746,7 +6746,7 @@ namespace ts {
return getUnionType(types);
}
const supertype = forEach(primaryTypes, t => isSupertypeOfEach(t, primaryTypes) ? t : undefined);
return supertype && addNullableKind(supertype, getCombinedFlagsOfTypes(types) & TypeFlags.Nullable);
return supertype && addTypeKind(supertype, getCombinedFlagsOfTypes(types) & TypeFlags.Nullable);
}

function reportNoCommonSupertypeError(types: Type[], errorLocation: Node, errorMessageChainHead: DiagnosticMessageChain): void {
Expand Down Expand Up @@ -6817,28 +6817,22 @@ namespace ts {
return !!(type.flags & TypeFlags.Tuple);
}

function getNullableKind(type: Type): TypeFlags {
let flags = type.flags;
if (flags & TypeFlags.Union) {
for (const t of (type as UnionType).types) {
flags |= t.flags;
}
}
return flags & TypeFlags.Nullable;
function getCombinedTypeFlags(type: Type): TypeFlags {
return type.flags & TypeFlags.Union ? getCombinedFlagsOfTypes((<UnionType>type).types) : type.flags;
}

function addNullableKind(type: Type, kind: TypeFlags): Type {
if ((getNullableKind(type) & kind) !== kind) {
const types = [type];
if (kind & TypeFlags.Undefined) {
types.push(undefinedType);
}
if (kind & TypeFlags.Null) {
types.push(nullType);
}
type = getUnionType(types);
function addTypeKind(type: Type, kind: TypeFlags) {
if ((getCombinedTypeFlags(type) & kind) === kind) {
return type;
}
return type;
const types = [type];
if (kind & TypeFlags.String) types.push(stringType);
if (kind & TypeFlags.Number) types.push(numberType);
if (kind & TypeFlags.Boolean) types.push(booleanType);
if (kind & TypeFlags.Void) types.push(voidType);
if (kind & TypeFlags.Undefined) types.push(undefinedType);
if (kind & TypeFlags.Null) types.push(nullType);
return getUnionType(types);
}

function getNonNullableType(type: Type): Type {
Expand Down Expand Up @@ -7667,7 +7661,7 @@ namespace ts {
if (!reference.flowNode || assumeInitialized && !(declaredType.flags & TypeFlags.Narrowable)) {
return declaredType;
}
const initialType = assumeInitialized ? declaredType : addNullableKind(declaredType, TypeFlags.Undefined);
const initialType = assumeInitialized ? declaredType : addTypeKind(declaredType, TypeFlags.Undefined);
const visitedFlowStart = visitedFlowCount;
const result = getTypeAtFlowNode(reference.flowNode);
visitedFlowCount = visitedFlowStart;
Expand Down Expand Up @@ -8163,7 +8157,7 @@ namespace ts {
getRootDeclaration(declaration).kind === SyntaxKind.Parameter || isInAmbientContext(declaration) ||
!isDeclarationIncludedInFlow(node, declaration, includeOuterFunctions);
const flowType = getFlowTypeOfReference(node, type, assumeInitialized, includeOuterFunctions);
if (!assumeInitialized && !(getNullableKind(type) & TypeFlags.Undefined) && getNullableKind(flowType) & TypeFlags.Undefined) {
if (!assumeInitialized && !(getCombinedTypeFlags(type) & TypeFlags.Undefined) && getCombinedTypeFlags(flowType) & TypeFlags.Undefined) {
error(node, Diagnostics.Variable_0_is_used_before_being_assigned, symbolToString(symbol));
// Return the declared type to reduce follow-on errors
return type;
Expand Down Expand Up @@ -9945,7 +9939,7 @@ namespace ts {
function checkNonNullExpression(node: Expression | QualifiedName) {
const type = checkExpression(node);
if (strictNullChecks) {
const kind = getNullableKind(type);
const kind = getCombinedTypeFlags(type) & TypeFlags.Nullable;
if (kind) {
error(node, kind & TypeFlags.Undefined ? kind & TypeFlags.Null ?
Diagnostics.Object_is_possibly_null_or_undefined :
Expand Down Expand Up @@ -11485,7 +11479,7 @@ namespace ts {
if (strictNullChecks) {
const declaration = symbol.valueDeclaration;
if (declaration && (<VariableLikeDeclaration>declaration).initializer) {
return addNullableKind(type, TypeFlags.Undefined);
return addTypeKind(type, TypeFlags.Undefined);
}
}
return type;
Expand Down Expand Up @@ -12411,7 +12405,7 @@ namespace ts {
case SyntaxKind.InKeyword:
return checkInExpression(left, right, leftType, rightType);
case SyntaxKind.AmpersandAmpersandToken:
return strictNullChecks ? addNullableKind(rightType, getNullableKind(leftType)) : rightType;
return strictNullChecks ? addTypeKind(rightType, getCombinedTypeFlags(leftType) & TypeFlags.Falsy) : rightType;
case SyntaxKind.BarBarToken:
return getUnionType([getNonNullableType(leftType), rightType]);
case SyntaxKind.EqualsToken:
Expand Down
1 change: 1 addition & 0 deletions src/compiler/types.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2209,6 +2209,7 @@ namespace ts {

/* @internal */
Nullable = Undefined | Null,
Falsy = String | Number | Boolean | Void | Undefined | Null,
/* @internal */
Intrinsic = Any | String | Number | Boolean | ESSymbol | Void | Undefined | Null | Never,
/* @internal */
Expand Down
156 changes: 156 additions & 0 deletions tests/baselines/reference/logicalAndOperatorStrictMode.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,156 @@
//// [logicalAndOperatorStrictMode.ts]

const a = [0];
const s = "";
const x = 0;
const b = false;
const v: void = undefined;
const u = undefined;
const n = null;
const z = s || x || u;

const a1 = a && a;
const a2 = a && s;
const a3 = a && x;
const a4 = a && b;
const a5 = a && v;
const a6 = a && u;
const a7 = a && n;
const a8 = a && z;

const s1 = s && a;
const s2 = s && s;
const s3 = s && x;
const s4 = s && b;
const s5 = s && v;
const s6 = s && u;
const s7 = s && n;
const s8 = s && z;

const x1 = x && a;
const x2 = x && s;
const x3 = x && x;
const x4 = x && b;
const x5 = x && v;
const x6 = x && u;
const x7 = x && n;
const x8 = x && z;

const b1 = b && a;
const b2 = b && s;
const b3 = b && x;
const b4 = b && b;
const b5 = b && v;
const b6 = b && u;
const b7 = b && n;
const b8 = b && z;

const v1 = v && a;
const v2 = v && s;
const v3 = v && x;
const v4 = v && b;
const v5 = v && v;
const v6 = v && u;
const v7 = v && n;
const v8 = v && z;

const u1 = u && a;
const u2 = u && s;
const u3 = u && x;
const u4 = u && b;
const u5 = u && v;
const u6 = u && u;
const u7 = u && n;
const u8 = u && z;

const n1 = n && a;
const n2 = n && s;
const n3 = n && x;
const n4 = n && b;
const n5 = n && v;
const n6 = n && u;
const n7 = n && n;
const n8 = n && z;

const z1 = z && a;
const z2 = z && s;
const z3 = z && x;
const z4 = z && b;
const z5 = z && v;
const z6 = z && u;
const z7 = z && n;
const z8 = z && z;

//// [logicalAndOperatorStrictMode.js]
var a = [0];
var s = "";
var x = 0;
var b = false;
var v = undefined;
var u = undefined;
var n = null;
var z = s || x || u;
var a1 = a && a;
var a2 = a && s;
var a3 = a && x;
var a4 = a && b;
var a5 = a && v;
var a6 = a && u;
var a7 = a && n;
var a8 = a && z;
var s1 = s && a;
var s2 = s && s;
var s3 = s && x;
var s4 = s && b;
var s5 = s && v;
var s6 = s && u;
var s7 = s && n;
var s8 = s && z;
var x1 = x && a;
var x2 = x && s;
var x3 = x && x;
var x4 = x && b;
var x5 = x && v;
var x6 = x && u;
var x7 = x && n;
var x8 = x && z;
var b1 = b && a;
var b2 = b && s;
var b3 = b && x;
var b4 = b && b;
var b5 = b && v;
var b6 = b && u;
var b7 = b && n;
var b8 = b && z;
var v1 = v && a;
var v2 = v && s;
var v3 = v && x;
var v4 = v && b;
var v5 = v && v;
var v6 = v && u;
var v7 = v && n;
var v8 = v && z;
var u1 = u && a;
var u2 = u && s;
var u3 = u && x;
var u4 = u && b;
var u5 = u && v;
var u6 = u && u;
var u7 = u && n;
var u8 = u && z;
var n1 = n && a;
var n2 = n && s;
var n3 = n && x;
var n4 = n && b;
var n5 = n && v;
var n6 = n && u;
var n7 = n && n;
var n8 = n && z;
var z1 = z && a;
var z2 = z && s;
var z3 = z && x;
var z4 = z && b;
var z5 = z && v;
var z6 = z && u;
var z7 = z && n;
var z8 = z && z;
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