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Improved detection of implicit type aliases.

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This commit is contained in:
Eric Traut 2020-09-23 20:07:30 -07:00
parent 120da9aa91
commit 90343f2d54
1 changed files with 29 additions and 19 deletions
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48
packages/pyright-internal/src/analyzer/typeEvaluator.ts
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@ -8951,6 +8951,8 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
}
let typeAliasNameNode: NameNode | undefined;
let isSpeculativeTypeAlias = false;
if (isDeclaredTypeAlias(node.leftExpression)) {
flags |=
EvaluatorFlags.ExpectingType |
@ -8961,6 +8963,7 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
} else if (isPossibleImplicitTypeAlias(node.leftExpression)) {
if (node.leftExpression.nodeType === ParseNodeType.Name) {
typeAliasNameNode = node.leftExpression;
isSpeculativeTypeAlias = true;
}
}
@ -9017,21 +9020,28 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
}
if (typeAliasNameNode) {
// If this is a type alias, record its name based on the assignment target.
rightHandType = transformTypeForTypeAlias(rightHandType, typeAliasNameNode);
// If this was a speculative type alias, it becomes a real type alias
// only if the evaluated type is an instantiable type.
if (
!isSpeculativeTypeAlias ||
(TypeBase.isInstantiable(rightHandType) && !isAnyOrUnknown(rightHandType))
) {
// If this is a type alias, record its name based on the assignment target.
rightHandType = transformTypeForTypeAlias(rightHandType, typeAliasNameNode);
if (isTypeAliasRecursive(typeAliasTypeVar!, rightHandType)) {
addDiagnostic(
fileInfo.diagnosticRuleSet.reportGeneralTypeIssues,
DiagnosticRule.reportGeneralTypeIssues,
Localizer.Diagnostic.typeAliasIsRecursive().format({ name: typeAliasNameNode.value }),
node.rightExpression
);
if (isTypeAliasRecursive(typeAliasTypeVar!, rightHandType)) {
addDiagnostic(
fileInfo.diagnosticRuleSet.reportGeneralTypeIssues,
DiagnosticRule.reportGeneralTypeIssues,
Localizer.Diagnostic.typeAliasIsRecursive().format({ name: typeAliasNameNode.value }),
node.rightExpression
);
}
// Set the resulting type to the boundType of the original type alias
// to support recursive type aliases.
typeAliasTypeVar!.details.boundType = rightHandType;
}
// Set the resulting type to the boundType of the original type alias
// to support recursive type aliases.
typeAliasTypeVar!.details.boundType = rightHandType;
}
}
}
@ -13347,6 +13357,7 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
// unless it's marked Final, is a constant, or is a declared type alias.
const fileInfo = getFileInfo(resolvedDecl.node);
let isSpeculativeTypeAliasFromPyTypedFile = false;
if (fileInfo.isInPyTypedPackage && !fileInfo.isStubFile && evaluatorOptions.disableInferenceForPyTypedSources) {
if (resolvedDecl.type !== DeclarationType.Variable) {
return UnknownType.create();
@ -13402,12 +13413,11 @@ export function createTypeEvaluator(importLookup: ImportLookup, evaluatorOptions
}
if (inferredType && resolvedDecl.typeAliasName) {
inferredType = transformTypeForTypeAlias(inferredType, resolvedDecl.typeAliasName);
// If this was a speculative type alias (i.e. not declared as a TypeAlias) that
// came from a py.typed package and it turned out not to be a real type alias,
// return Unknown.
if (isSpeculativeTypeAliasFromPyTypedFile && !inferredType.typeAliasInfo) {
// If this was a speculative type alias, it becomes a real type alias only
// in the event that its inferred type is instantiable.
if (TypeBase.isInstantiable(inferredType) && !isAnyOrUnknown(inferredType)) {
inferredType = transformTypeForTypeAlias(inferredType, resolvedDecl.typeAliasName);
} else if (isSpeculativeTypeAliasFromPyTypedFile) {
return UnknownType.create();
}
}