Turn block into a closure in test macro#27
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bartlomieju merged 1 commit intodenoland:mainfrom Sep 14, 2020
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The `doc_test!` macro defines two local variables (`entries` and `doc`),
which are then accessed from the provided `block`.
However, this only compiled due to a bug in rustc: substituted
metavariables cannot refer to names defined within the macro body. For
example, the following ode does not compile:
```rust
macro_rules! foo {
($block:expr) => {
let mut bar = false;
$block
}
}
fn main() {
foo!({bar = true});
}
```
In this case, the `doc_test!` macro was incorrectly allowed to compile
due to the presence of the `#[tokio::test]` macro on the enclosing
function. When the underlying compiler bug is fixed in
rust-lang/rust#75800,
this macro will stop compiling.
I've adjusted the macro to take in a closure instead of a block. This
closure is invoked with the `entries` and `doc` variables, allowing it
to compile with both old and new compilers.
If you have any questions about this change, feel free to ask me.
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Member
|
@Aaron1011 nice catch and thanks for the patch! CC @SyrupThinker PTAL |
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Looks good to me |
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The
doc_test!macro defines two local variables (entriesanddoc),which are then accessed from the provided
block.However, this only compiled due to a bug in rustc: substituted
metavariables cannot refer to names defined within the macro body. For
example, the following ode does not compile:
In this case, the
doc_test!macro was incorrectly allowed to compiledue to the presence of the
#[tokio::test]macro on the enclosingfunction. When the underlying compiler bug is fixed in
rust-lang/rust#75800,
this macro will stop compiling.
I've adjusted the macro to take in a closure instead of a block. This
closure is invoked with the
entriesanddocvariables, allowing itto compile with both old and new compilers.
If you have any questions about this change, feel free to ask me.