Error: Smithy typescript codegen generates un-buildable code for awsJson services when using streaming

[AnirudhKonduru]

Produces the following output when npm run build is run:

> concurrently 'yarn:build:cjs' 'yarn:build:es' 'yarn:build:types'
...
$ tsc -p tsconfig.types.json
[build:cjs] src/protocols/Aws_json1_0.ts(52,36): error TS2552: Cannot find name 'de_string'. Did you mean 'String'?
error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
[build:cjs] yarn run build:cjs exited with code 2
[build:types] src/protocols/Aws_json1_0.ts(52,36): error TS2552: Cannot find name 'de_string'. Did you mean 'String'?
[build:es] src/protocols/Aws_json1_0.ts(52,36): error TS2552: Cannot find name 'de_string'. Did you mean 'String'?
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
[build:types] yarn run build:types exited with code 1
error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
[build:es] yarn run build:es exited with code 2

To reproduce, build this minimal main.smithy file:

$version: "2"

namespace smithy.example
use aws.protocols#awsJson1_0

@awsJson1_0
service ExampleService {
    version: "2022-01-01"
    operations: [Echo]
}

structure MessageItem {
    content: String
}
@streaming
union MessageStream {
    content: MessageItem
}

@output
structure EchoResponse {
    @httpHeader("x-custom-header")
    customHeader: String
    @httpPayload
    stream: MessageStream
}

@http(code: 200, method: "POST", uri: "/echo")
operation Echo {
    input := {
        message: String
    } 
    output: EchoResponse
}

With the following dependencies:

"software.amazon.smithy.typescript:smithy-typescript-codegen:0.18.0",
"software.amazon.smithy.typescript:smithy-aws-typescript-codegen:0.18.0",
"software.amazon.smithy:smithy-aws-traits:1.39.0"

Tested with smithy-cli versions 1.33, 1.34, 1.40.

[AnirudhKonduru]

I should add that this seems to be broken if we're using @awsJson1, but not with @restJson.
It also happens only if the output structure has both, a field marked with @httpPayload who's type is @streaming and a field marked with @httpHeader along side it. Removing any of these will let it generate buildable code.

[kuhe]

We're planning to include a fix for this issue in v0.32.0, the next minor version.