Missing conjure-imports can cause misleading errors

[tjwilson90]

With the following input

# foo.yml
types:
  conjure-imports:
    bar: bar.yml

  definitions:
    default-package: test
    objects:
      Foo:
        fields:
          bar: bar.Bar

# bar.yml
types:
  definitions:
    default-package: test
    objects:
      Bar:
        fields:
          baz: baz.Baz

# baz.yml
types:
  definitions:
    default-package: test
    objects:
      Baz:
        alias: string

I get the error

java.lang.RuntimeException: Encountered error trying to parse file '/Volumes/git/code/gaia/cosmos/cosmos-api/build/conjure/foo.yml'
        at com.palantir.conjure.defs.ConjureParserUtils.lambda$parseConjureDef$3(ConjureParserUtils.java:228)
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
        at com.palantir.conjure.defs.ConjureParserUtils.parseConjureDef(ConjureParserUtils.java:199)
        at com.palantir.conjure.defs.Conjure.parse(Conjure.java:37)
        at com.palantir.conjure.cli.ConjureCli$CompileCommand.generate(ConjureCli.java:91)
        at com.palantir.conjure.cli.ConjureCli$CompileCommand.run(ConjureCli.java:85)
        at picocli.CommandLine.executeUserObject(CommandLine.java:1919)
        at picocli.CommandLine.access$1100(CommandLine.java:145)
        at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2332)
        at picocli.CommandLine$RunLast.handle(CommandLine.java:2326)
        at picocli.CommandLine$RunLast.handle(CommandLine.java:2291)
        at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2159)
        at picocli.CommandLine.execute(CommandLine.java:2058)
        at com.palantir.conjure.cli.ConjureCli.main(ConjureCli.java:46)
  Caused by: java.lang.NullPointerException: Import not found for namespace: Namespace{name=baz}
        at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:987)
        at com.palantir.conjure.defs.ConjureTypeParserVisitor$ByParsedRepresentationTypeNameResolver.resolve(ConjureTypeParserVisitor.java:66)
        at com.palantir.conjure.defs.ConjureTypeParserVisitor.visitForeignReference(ConjureTypeParserVisitor.java:143)
        at com.palantir.conjure.defs.ConjureTypeParserVisitor.visitForeignReference(ConjureTypeParserVisitor.java:41)
        at com.palantir.conjure.parser.types.reference.ForeignReferenceType.visit(ForeignReferenceType.java:33)
        at com.palantir.conjure.defs.ConjureParserUtils.lambda$parseField$10(ConjureParserUtils.java:334)
        at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
        at java.base/java.util.Collections$2.tryAdvance(Collections.java:4745)
        at java.base/java.util.Collections$2.forEachRemaining(Collections.java:4753)
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
        at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
        at com.palantir.conjure.defs.ConjureParserUtils.parseField(ConjureParserUtils.java:341)
        at com.palantir.conjure.defs.ConjureParserUtils.parseObjectType(ConjureParserUtils.java:162)
        at com.palantir.conjure.defs.TypeDefinitionParserVisitor.visit(TypeDefinitionParserVisitor.java:56)
        at com.palantir.conjure.defs.TypeDefinitionParserVisitor.visit(TypeDefinitionParserVisitor.java:28)
        at com.palantir.conjure.parser.types.complex.ObjectTypeDefinition.visit(ObjectTypeDefinition.java:42)
        at com.palantir.conjure.defs.ConjureParserUtils.lambda$parseObjects$6(ConjureParserUtils.java:293)
        at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
        at java.base/java.util.Collections$2.tryAdvance(Collections.java:4745)
        at java.base/java.util.Collections$2.forEachRemaining(Collections.java:4753)
        at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
        at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
        at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
        at com.palantir.conjure.defs.ConjureParserUtils.parseObjects(ConjureParserUtils.java:294)
        at com.palantir.conjure.defs.ConjureParserUtils.lambda$parseImportObjects$4(ConjureParserUtils.java:253)
        at java.base/java.util.Collections$SingletonSet.forEach(Collections.java:4795)
        at com.palantir.conjure.defs.ConjureParserUtils.parseImportObjects(ConjureParserUtils.java:248)
        at com.palantir.conjure.defs.ConjureParserUtils.lambda$parseConjureDef$3(ConjureParserUtils.java:209)
        ... 13 more

which suggests that my error is in foo.yml when the actual error is in bar.yml.