Function getConstraintFromTypeParameter

test/fixtures/snapshot/typescript.js:60135–60158

This is a worker function. Use getConstraintOfTypeParameter which guards against circular constraints.

(typeParameter)

        }
        /** This is a worker function. Use getConstraintOfTypeParameter which guards against circular constraints. */
        function getConstraintFromTypeParameter(typeParameter) {
            if (!typeParameter.constraint) {
                if (typeParameter.target) {
                    var targetConstraint = getConstraintOfTypeParameter(typeParameter.target);
                    typeParameter.constraint = targetConstraint ? instantiateType(targetConstraint, typeParameter.mapper) : noConstraintType;
                }
                else {
                    var constraintDeclaration = getConstraintDeclaration(typeParameter);
                    if (!constraintDeclaration) {
                        typeParameter.constraint = getInferredTypeParameterConstraint(typeParameter) || noConstraintType;
                    }
                    else {
                        var type = getTypeFromTypeNode(constraintDeclaration);
                        if (type.flags & 1 /* TypeFlags.Any */ && !isErrorType(type)) { // Allow errorType to propegate to keep downstream errors suppressed
                            // use keyofConstraintType as the base constraint for mapped type key constraints (unknown isn;t assignable to that, but `any` was),
                            // use unknown otherwise
                            type = constraintDeclaration.parent.parent.kind === 195 /* SyntaxKind.MappedType */ ? keyofConstraintType : unknownType;
                        }
                        typeParameter.constraint = type;
                    }
                }
            }
            return typeParameter.constraint === noConstraintType ? undefined : typeParameter.constraint;
        }
        function getParentSymbolOfTypeParameter(typeParameter) {
            var tp = ts.getDeclarationOfKind(typeParameter.symbol, 163 /* SyntaxKind.TypeParameter */);
            var host = ts.isJSDocTemplateTag(tp.parent) ? ts.getEffectiveContainerForJSDocTemplateTag(tp.parent) : tp.parent;