ICE: `invalid Immediate For Given Destination Place: Value ScalarPair Does Not Match ABI Scalar`

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Introduction

This article discusses an internal compiler error (ICE) encountered while compiling a Rust program. The error message indicates that there is an issue with the immediate value for a given destination place, specifically with a ScalarPair value that does not match the ABI Scalar type.

Background

The ICE is related to the Rust compiler's ability to evaluate constants at compile-time. The compiler uses a mechanism called "const evaluation" to evaluate expressions and determine their values at compile-time. This can improve performance by reducing the amount of work that needs to be done at runtime.

Error Message

The error message is as follows:

error: internal compiler error: compiler/rustc_const_eval/src/interpret/operand.rs:157:17: invalid immediate for given destination place: value ScalarPair(alloc4<imm>, 0x0000000000000003) does not match ABI Scalar(Initialized { value: Pointer(AddressSpace(0)), valid_range: 1..=18446744073709551615 }))

This message indicates that there is an issue with the immediate value for a given destination place, specifically with a ScalarPair value that does not match the ABI Scalar type.

Code

The code that triggered this ICE is as follows:

fn test()
where
    for<'a> <Foo<'a> as Bar>::Type: Sized,
{
    'b: {
        println!("hi");
        
        'c: 
        
        if true {
            break 'b;
        }
    }
}

This code defines a function test that has a where clause that specifies a trait bound on the type Foo. The trait bound is that the type Foo must implement the trait Bar for all lifetimes 'a.

Analysis

The ICE is likely caused by a bug in the Rust compiler's const evaluation mechanism. The bug is related to the way that the compiler handles ScalarPair values and their relationship to ABI Scalar types.

Solution

To fix this ICE, we need to identify the root cause of the issue and modify the Rust compiler's const evaluation mechanism to handle ScalarPair values correctly. This may involve updating the compiler's code to correctly handle the relationship between ScalarPair values and ABI Scalar types.

Related Issues

This ICE is likely related to other issues in the Rust compiler's const evaluation mechanism. Some possible related issues include:

  • rust-lang/rust#...: This issue reports a similar ICE caused by a bug in the const evaluation mechanism.
  • rust-lang/rust#...: This issue reports a bug in the const evaluation mechanism that causes incorrect results for certain expressions.

Conclusion

In conclusion, this article discusses an ICE encountered while compiling a Rust program. The error message indicates that there is an issue with the immediate value for a given destination place, specifically with a ScalarPair value that does not match the ABI Scalar type. To fix this ICE, we need to identify the root cause of the issue and modify the Rust compiler's const evaluation mechanism to handle ScalarPair values correctly.

Additional Information

  • The ICE is likely caused by a bug in the Rust compiler's const evaluation mechanism.
  • The bug is related to the way that the compiler handles ScalarPair values and their relationship to ABI Scalar types.
  • To fix this ICE, we need to update the compiler's code to correctly handle the relationship between ScalarPair values and ABI Scalar types.
  • This ICE is likely related to other issues in the Rust compiler's const evaluation mechanism.

Possible Solutions

  • Update the compiler's code to correctly handle the relationship between ScalarPair values and ABI Scalar types.
  • Modify the const evaluation mechanism to handle ScalarPair values correctly.
  • Add additional checks to the const evaluation mechanism to prevent similar ICEs from occurring in the future.

Related Code

  • The code that triggered this ICE is as follows:
fn test()
where
    for<'a> <Foo<'a> as Bar>::Type: Sized,
{
    'b: {
        println!("hi");
        
        'c: 
        
        if true {
            break 'b;
        }
    }
}

This code defines a function test that has a where clause that specifies a trait bound on the type Foo. The trait bound is that the type Foo must implement the trait Bar for all lifetimes 'a.

Additional Resources

  • Rust Language Reference: This document provides information on the Rust language and its data types.
  • Rust Compiler Internals: This document provides information on the Rust compiler's internals and how it works.
  • Rust Const Evaluation: This document provides information on the Rust compiler's const evaluation mechanism and how it works.

Q: What is an ICE in Rust?

A: An ICE (Internal Compiler Error) is an error that occurs within the Rust compiler itself, rather than in the code being compiled. It's a bug in the compiler that prevents it from functioning correctly.

Q: What is the error message invalid immediate for given destination place: value ScalarPair does not match ABI Scalar?

A: This error message indicates that there is an issue with the immediate value for a given destination place, specifically with a ScalarPair value that does not match the ABI Scalar type.

Q: What is a ScalarPair value?

A: A ScalarPair value is a type of value that represents a pair of scalar values. In the context of this error, it's likely that the ScalarPair value is not being handled correctly by the compiler.

Q: What is an ABI Scalar type?

A: An ABI Scalar type is a type of scalar value that is defined by the Application Binary Interface (ABI) of the Rust compiler. It's a type of value that is used to represent scalar values in a way that is compatible with the ABI.

Q: How can I fix this ICE?

A: To fix this ICE, you'll need to identify the root cause of the issue and modify the Rust compiler's const evaluation mechanism to handle ScalarPair values correctly. This may involve updating the compiler's code to correctly handle the relationship between ScalarPair values and ABI Scalar types.

Q: What are some possible solutions to this ICE?

A: Some possible solutions to this ICE include:

  • Updating the compiler's code to correctly handle the relationship between ScalarPair values and ABI Scalar types.
  • Modifying the const evaluation mechanism to handle ScalarPair values correctly.
  • Adding additional checks to the const evaluation mechanism to prevent similar ICEs from occurring in the future.

Q: What are some related issues that may be relevant to this ICE?

A: Some related issues that may be relevant to this ICE include:

  • rust-lang/rust#...: This issue reports a similar ICE caused by a bug in the const evaluation mechanism.
  • rust-lang/rust#...: This issue reports a bug in the const evaluation mechanism that causes incorrect results for certain expressions.

Q: Where can I find more information on the Rust compiler's internals?

A: You can find more information on the Rust compiler's internals in the following resources:

  • Rust Compiler Internals: This document provides information on the Rust compiler's internals and how it works.
  • Rust Const Evaluation: This document provides information on the Rust compiler's const evaluation mechanism and how it works.

Q: How can I report a bug in the Rust compiler?

A: You can report a bug in the Rust compiler by filing an issue on the Rust GitHub repository. Be sure to include as much information as possible about the bug, including the error message and any relevant code.