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rbucktonrbuckton
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Merge pull request microsoft#30259 from Microsoft/transformFlagCleanup
Transform flag cleanup
2 parents 58e847a + 1c0f9a8 commit 6607e00

27 files changed

+478
-638
lines changed

‎src/compiler/binder.ts

Lines changed: 18 additions & 101 deletions
Original file line numberDiff line numberDiff line change
@@ -3093,32 +3093,24 @@ namespace ts {
30933093

30943094
function computeCallExpression(node: CallExpression, subtreeFlags: TransformFlags) {
30953095
let transformFlags = subtreeFlags;
3096+
const callee = skipOuterExpressions(node.expression);
30963097
const expression = node.expression;
30973098

30983099
if (node.typeArguments) {
30993100
transformFlags |= TransformFlags.AssertTypeScript;
31003101
}
31013102

3102-
if (subtreeFlags & TransformFlags.ContainsRestOrSpread
3103-
|| (expression.transformFlags & (TransformFlags.Super | TransformFlags.ContainsSuper))) {
3103+
if (subtreeFlags & TransformFlags.ContainsRestOrSpread || isSuperOrSuperProperty(callee)) {
31043104
// If the this node contains a SpreadExpression, or is a super call, then it is an ES6
31053105
// node.
31063106
transformFlags |= TransformFlags.AssertES2015;
3107-
// super property or element accesses could be inside lambdas, etc, and need a captured `this`,
3108-
// while super keyword for super calls (indicated by TransformFlags.Super) does not (since it can only be top-level in a constructor)
3109-
if (expression.transformFlags & TransformFlags.ContainsSuper) {
3107+
if (isSuperProperty(callee)) {
31103108
transformFlags |= TransformFlags.ContainsLexicalThis;
31113109
}
31123110
}
31133111

31143112
if (expression.kind === SyntaxKind.ImportKeyword) {
31153113
transformFlags |= TransformFlags.ContainsDynamicImport;
3116-
3117-
// A dynamic 'import()' call that contains a lexical 'this' will
3118-
// require a captured 'this' when emitting down-level.
3119-
if (subtreeFlags & TransformFlags.ContainsLexicalThis) {
3120-
transformFlags |= TransformFlags.ContainsCapturedLexicalThis;
3121-
}
31223114
}
31233115

31243116
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
@@ -3191,7 +3183,7 @@ namespace ts {
31913183
// If a parameter has an initializer, a binding pattern or a dotDotDot token, then
31923184
// it is ES6 syntax and its container must emit default value assignments or parameter destructuring downlevel.
31933185
if (subtreeFlags & TransformFlags.ContainsBindingPattern || initializer || dotDotDotToken) {
3194-
transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsDefaultValueAssignments;
3186+
transformFlags |= TransformFlags.AssertES2015;
31953187
}
31963188

31973189
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
@@ -3202,7 +3194,6 @@ namespace ts {
32023194
let transformFlags = subtreeFlags;
32033195
const expression = node.expression;
32043196
const expressionKind = expression.kind;
3205-
const expressionTransformFlags = expression.transformFlags;
32063197

32073198
// If the node is synthesized, it means the emitter put the parentheses there,
32083199
// not the user. If we didn't want them, the emitter would not have put them
@@ -3212,12 +3203,6 @@ namespace ts {
32123203
transformFlags |= TransformFlags.AssertTypeScript;
32133204
}
32143205

3215-
// If the expression of a ParenthesizedExpression is a destructuring assignment,
3216-
// then the ParenthesizedExpression is a destructuring assignment.
3217-
if (expressionTransformFlags & TransformFlags.DestructuringAssignment) {
3218-
transformFlags |= TransformFlags.DestructuringAssignment;
3219-
}
3220-
32213206
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
32223207
return transformFlags & ~TransformFlags.OuterExpressionExcludes;
32233208
}
@@ -3241,12 +3226,6 @@ namespace ts {
32413226
|| node.typeParameters) {
32423227
transformFlags |= TransformFlags.AssertTypeScript;
32433228
}
3244-
3245-
if (subtreeFlags & TransformFlags.ContainsLexicalThisInComputedPropertyName) {
3246-
// A computed property name containing `this` might need to be rewritten,
3247-
// so propagate the ContainsLexicalThis flag upward.
3248-
transformFlags |= TransformFlags.ContainsLexicalThis;
3249-
}
32503229
}
32513230

32523231
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
@@ -3264,12 +3243,6 @@ namespace ts {
32643243
transformFlags |= TransformFlags.AssertTypeScript;
32653244
}
32663245

3267-
if (subtreeFlags & TransformFlags.ContainsLexicalThisInComputedPropertyName) {
3268-
// A computed property name containing `this` might need to be rewritten,
3269-
// so propagate the ContainsLexicalThis flag upward.
3270-
transformFlags |= TransformFlags.ContainsLexicalThis;
3271-
}
3272-
32733246
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
32743247
return transformFlags & ~TransformFlags.ClassExcludes;
32753248
}
@@ -3374,7 +3347,7 @@ namespace ts {
33743347
}
33753348

33763349
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
3377-
return transformFlags & ~TransformFlags.MethodOrAccessorExcludes;
3350+
return propagatePropertyNameFlags(node.name, transformFlags & ~TransformFlags.MethodOrAccessorExcludes);
33783351
}
33793352

33803353
function computeAccessor(node: AccessorDeclaration, subtreeFlags: TransformFlags) {
@@ -3396,7 +3369,7 @@ namespace ts {
33963369
}
33973370

33983371
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
3399-
return transformFlags & ~TransformFlags.MethodOrAccessorExcludes;
3372+
return propagatePropertyNameFlags(node.name, transformFlags & ~TransformFlags.MethodOrAccessorExcludes);
34003373
}
34013374

34023375
function computePropertyDeclaration(node: PropertyDeclaration, subtreeFlags: TransformFlags) {
@@ -3410,7 +3383,7 @@ namespace ts {
34103383
}
34113384

34123385
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
3413-
return transformFlags & ~TransformFlags.NodeExcludes;
3386+
return propagatePropertyNameFlags(node.name, transformFlags & ~TransformFlags.PropertyExcludes);
34143387
}
34153388

34163389
function computeFunctionDeclaration(node: FunctionDeclaration, subtreeFlags: TransformFlags) {
@@ -3444,13 +3417,6 @@ namespace ts {
34443417
transformFlags |= TransformFlags.AssertES2018;
34453418
}
34463419

3447-
// If a FunctionDeclaration's subtree has marked the container as needing to capture the
3448-
// lexical this, or the function contains parameters with initializers, then this node is
3449-
// ES6 syntax.
3450-
if (subtreeFlags & TransformFlags.ES2015FunctionSyntaxMask) {
3451-
transformFlags |= TransformFlags.AssertES2015;
3452-
}
3453-
34543420
// If a FunctionDeclaration is generator function and is the body of a
34553421
// transformed async function, then this node can be transformed to a
34563422
// down-level generator.
@@ -3486,14 +3452,6 @@ namespace ts {
34863452
transformFlags |= TransformFlags.AssertES2018;
34873453
}
34883454

3489-
3490-
// If a FunctionExpression's subtree has marked the container as needing to capture the
3491-
// lexical this, or the function contains parameters with initializers, then this node is
3492-
// ES6 syntax.
3493-
if (subtreeFlags & TransformFlags.ES2015FunctionSyntaxMask) {
3494-
transformFlags |= TransformFlags.AssertES2015;
3495-
}
3496-
34973455
// If a FunctionExpression is generator function and is the body of a
34983456
// transformed async function, then this node can be transformed to a
34993457
// down-level generator.
@@ -3527,11 +3485,6 @@ namespace ts {
35273485
transformFlags |= TransformFlags.AssertES2018;
35283486
}
35293487

3530-
// If an ArrowFunction contains a lexical this, its container must capture the lexical this.
3531-
if (subtreeFlags & TransformFlags.ContainsLexicalThis) {
3532-
transformFlags |= TransformFlags.ContainsCapturedLexicalThis;
3533-
}
3534-
35353488
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
35363489
return transformFlags & ~TransformFlags.ArrowFunctionExcludes;
35373490
}
@@ -3541,11 +3494,10 @@ namespace ts {
35413494

35423495
// If a PropertyAccessExpression starts with a super keyword, then it is
35433496
// ES6 syntax, and requires a lexical `this` binding.
3544-
if (transformFlags & TransformFlags.Super) {
3545-
transformFlags ^= TransformFlags.Super;
3497+
if (node.expression.kind === SyntaxKind.SuperKeyword) {
35463498
// super inside of an async function requires hoisting the super access (ES2017).
35473499
// same for super inside of an async generator, which is ES2018.
3548-
transformFlags |= TransformFlags.ContainsSuper | TransformFlags.ContainsES2017 | TransformFlags.ContainsES2018;
3500+
transformFlags |= TransformFlags.ContainsES2017 | TransformFlags.ContainsES2018;
35493501
}
35503502

35513503
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
@@ -3554,16 +3506,13 @@ namespace ts {
35543506

35553507
function computeElementAccess(node: ElementAccessExpression, subtreeFlags: TransformFlags) {
35563508
let transformFlags = subtreeFlags;
3557-
const expression = node.expression;
3558-
const expressionFlags = expression.transformFlags; // We do not want to aggregate flags from the argument expression for super/this capturing
35593509

35603510
// If an ElementAccessExpression starts with a super keyword, then it is
35613511
// ES6 syntax, and requires a lexical `this` binding.
3562-
if (expressionFlags & TransformFlags.Super) {
3563-
transformFlags &= ~TransformFlags.Super;
3512+
if (node.expression.kind === SyntaxKind.SuperKeyword) {
35643513
// super inside of an async function requires hoisting the super access (ES2017).
35653514
// same for super inside of an async generator, which is ES2018.
3566-
transformFlags |= TransformFlags.ContainsSuper | TransformFlags.ContainsES2017 | TransformFlags.ContainsES2018;
3515+
transformFlags |= TransformFlags.ContainsES2017 | TransformFlags.ContainsES2018;
35673516
}
35683517

35693518
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
@@ -3572,7 +3521,7 @@ namespace ts {
35723521

35733522
function computeVariableDeclaration(node: VariableDeclaration, subtreeFlags: TransformFlags) {
35743523
let transformFlags = subtreeFlags;
3575-
transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern;
3524+
transformFlags |= TransformFlags.AssertES2015 | TransformFlags.ContainsBindingPattern; // TODO(rbuckton): Why are these set unconditionally?
35763525

35773526
// A VariableDeclaration containing ObjectRest is ES2018 syntax
35783527
if (subtreeFlags & TransformFlags.ContainsObjectRestOrSpread) {
@@ -3634,15 +3583,7 @@ namespace ts {
36343583
}
36353584

36363585
function computeExpressionStatement(node: ExpressionStatement, subtreeFlags: TransformFlags) {
3637-
let transformFlags = subtreeFlags;
3638-
3639-
// If the expression of an expression statement is a destructuring assignment,
3640-
// then we treat the statement as ES6 so that we can indicate that we do not
3641-
// need to hold on to the right-hand side.
3642-
if (node.expression.transformFlags & TransformFlags.DestructuringAssignment) {
3643-
transformFlags |= TransformFlags.AssertES2015;
3644-
}
3645-
3586+
const transformFlags = subtreeFlags;
36463587
node.transformFlags = transformFlags | TransformFlags.HasComputedFlags;
36473588
return transformFlags & ~TransformFlags.NodeExcludes;
36483589
}
@@ -3815,17 +3756,6 @@ namespace ts {
38153756
// This is so that they can flow through PropertyName transforms unaffected.
38163757
// Instead, we mark the container as ES6, so that it can properly handle the transform.
38173758
transformFlags |= TransformFlags.ContainsComputedPropertyName;
3818-
if (subtreeFlags & TransformFlags.ContainsLexicalThis) {
3819-
// A computed method name like `[this.getName()](x: string) { ... }` needs to
3820-
// distinguish itself from the normal case of a method body containing `this`:
3821-
// `this` inside a method doesn't need to be rewritten (the method provides `this`),
3822-
// whereas `this` inside a computed name *might* need to be rewritten if the class/object
3823-
// is inside an arrow function:
3824-
// `_this = this; () => class K { [_this.getName()]() { ... } }`
3825-
// To make this distinction, use ContainsLexicalThisInComputedPropertyName
3826-
// instead of ContainsLexicalThis for computed property names
3827-
transformFlags |= TransformFlags.ContainsLexicalThisInComputedPropertyName;
3828-
}
38293759
break;
38303760

38313761
case SyntaxKind.SpreadElement:
@@ -3838,7 +3768,7 @@ namespace ts {
38383768

38393769
case SyntaxKind.SuperKeyword:
38403770
// This node is ES6 syntax.
3841-
transformFlags |= TransformFlags.AssertES2015 | TransformFlags.Super;
3771+
transformFlags |= TransformFlags.AssertES2015;
38423772
excludeFlags = TransformFlags.OuterExpressionExcludes; // must be set to persist `Super`
38433773
break;
38443774

@@ -3880,12 +3810,6 @@ namespace ts {
38803810
transformFlags |= TransformFlags.AssertES2015;
38813811
}
38823812

3883-
if (subtreeFlags & TransformFlags.ContainsLexicalThisInComputedPropertyName) {
3884-
// A computed property name containing `this` might need to be rewritten,
3885-
// so propagate the ContainsLexicalThis flag upward.
3886-
transformFlags |= TransformFlags.ContainsLexicalThis;
3887-
}
3888-
38893813
if (subtreeFlags & TransformFlags.ContainsObjectRestOrSpread) {
38903814
// If an ObjectLiteralExpression contains a spread element, then it
38913815
// is an ES2018 node.
@@ -3895,14 +3819,7 @@ namespace ts {
38953819
break;
38963820

38973821
case SyntaxKind.ArrayLiteralExpression:
3898-
case SyntaxKind.NewExpression:
38993822
excludeFlags = TransformFlags.ArrayLiteralOrCallOrNewExcludes;
3900-
if (subtreeFlags & TransformFlags.ContainsRestOrSpread) {
3901-
// If the this node contains a SpreadExpression, then it is an ES6
3902-
// node.
3903-
transformFlags |= TransformFlags.AssertES2015;
3904-
}
3905-
39063823
break;
39073824

39083825
case SyntaxKind.DoStatement:
@@ -3917,10 +3834,6 @@ namespace ts {
39173834
break;
39183835

39193836
case SyntaxKind.SourceFile:
3920-
if (subtreeFlags & TransformFlags.ContainsCapturedLexicalThis) {
3921-
transformFlags |= TransformFlags.AssertES2015;
3922-
}
3923-
39243837
break;
39253838

39263839
case SyntaxKind.ReturnStatement:
@@ -3938,6 +3851,10 @@ namespace ts {
39383851
return transformFlags & ~excludeFlags;
39393852
}
39403853

3854+
function propagatePropertyNameFlags(node: PropertyName, transformFlags: TransformFlags) {
3855+
return transformFlags | (node.transformFlags & TransformFlags.PropertyNamePropagatingFlags);
3856+
}
3857+
39413858
/**
39423859
* Gets the transform flags to exclude when unioning the transform flags of a subtree.
39433860
*

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