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Topaz6.0 · Before release
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Specification 6.0 · Not released · Tested product 5.21.3

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Type an API name, diagnostic number, rule, or project topic.

    Diagnostics

    TPZ5534: Type is not JSON decodable

    A typed JSON decode target is not a supported concrete Topaz data shape.

    Diagnostic and cause

    Link

    Type is not JSON decodable

    Family
    topaz
    Phase
    check
    Code
    TPZ5534

    Cause and conditions

    json.parseAs requires an explicit JSON-decodable result type. Calling json.parseAs("1") without a type argument is rejected with TPZ5534; json.parseAs<int>("1") is accepted.

    Related rule: Typed JSON decoding needs a type argument

    Response

    Supply the target type after json.parseAs, such as json.parseAs<int>("1"). Choose a JSON-decodable type for the result.

    Source evidence

    Compiler phase: check.

    Compiler explanation: A typed JSON decode target is not a supported concrete Topaz data shape.

    Message templates. The marker ⟨value⟩ stands for text computed for the reported program.

    • ⟨value⟩ requires an explicit type argument, e.g. ⟨value⟩<User>(...) Source
    • ⟨value⟩ is not JSON-decodable, so ⟨value⟩ cannot decode into it Source

    json.parseAs requires an explicit decodable result type. A call without type arguments is rejected with TPZ5534 even when its text contains a valid JSON integer.

    Rulediagnostics.tpz5534.p5.rule

    Typed JSON decoding needs a type argument

    json.parseAs requires an explicit JSON-decodable result type. Calling json.parseAs("1") without a type argument is rejected with TPZ5534; json.parseAs<int>("1") is accepted.

    Examples Rejected programRepaired program

    Diagnostics TPZ5534

    Source evidence

    Response

    Link

    Supply the target type after json.parseAs, such as json.parseAs<int>("1"). Choose a JSON-decodable type for the result.

    Reproduction and verification

    Link

    Rejected program

    Link

    reject · check · Verification: not-run

    example.tpzRejected programOpen in Playground
    1. import std.json
    2. let decoded = json.parseAs("1")
    Expected outputNonzero exit
    No stdout.
    $ topaz check example.tpz · target product 5.21.3
    Expected result

    Expected result

    Rejection during check. Nonzero exit.

    • TPZ5534 diagnostic-tpz5534 at example.tpz:2:15

    No stdout.

    This exact example has not been executed.

    A bare call without type arguments can also report TPZ5020 for missing contextual type. The diagnostic assertion requires TPZ5534 and permits that accompanying diagnostic.

    Source evidence

    Repaired program

    Link

    check · check · Verification: not-run

    example.tpzRepaired program
    1. import std.json
    2. let decoded = json.parseAs<int>("1")
    Expected outputexit 0
    $ topaz check example.tpz · target product 5.21.3
    Expected result

    Expected result

    Checking accepts the program. Exit code 0.

    No stderr.

    This exact example has not been executed.

    A bare call without type arguments can also report TPZ5020 for missing contextual type. The diagnostic assertion requires TPZ5534 and permits that accompanying diagnostic.

    Source evidence

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