Errors from cargo build.rs script do not appear in vscode problem view when command line cargo build fails as expected

[bruceskingle]

I am developing a code generator as a rust build script.

Errors and warnings in rust code appear in the Problems view of vscode and the output of cargo build, as expected.
Errors generated by build.rs are detected by cargo build and cause the build to fail:

warning: unused variable: `error`
  --> sparko_graphql_builder_test/build.rs:11:16
   |
11 |     if let Err(error) = build() {
   |                ^^^^^ help: if this is intentional, prefix it with an underscore: `_error`
   |
   = note: `#[warn(unused_variables)]` on by default

warning: `sparko_graphql_builder_test` (build script) generated 1 warning
error: [email protected]: OptionalNonNullFieldError(Pos(4:5), "float")
warning: [email protected]: Build failed with 1 errors and 0 warnings
error: failed to run custom build command for `sparko_graphql_builder_test v0.1.0 (/Users/bruce/git/sparko_graphql/sparko_graphql_builder_test)`
note: To improve backtraces for build dependencies, set the CARGO_PROFILE_DEV_BUILD_OVERRIDE_DEBUG=true environment variable to enable debug information generation.

Caused by:
  process didn't exit successfully: `/Users/bruce/git/sparko_graphql/target/debug/build/sparko_graphql_builder_test-980f47bb930579b0/build-script-build` (exit status: 1)
  --- stdout
  cargo::rerun-if-changed=build.rs
  cargo::rerun-if-changed=graphql_builder/src/lib.rs
  cargo::rerun-if-changed=graphql/schema/example.graphql
  cargo::rerun-if-changed=graphql/query/example/get-luke.graphql
  cargo::error=OptionalNonNullFieldError(Pos(4:5), "float")

  cargo::warning=Build failed with 1 errors and 0 warnings
% 

The unused variable warning above appears in the vscode problems view, but the errors and warnings from build.rs do not.

build.rs is reporting errors by emitting lines like

cargo::error=OptionalNonNullFieldError(Pos(4:5), "float")

on stdout.

The builder crate and a test crate for it are both in a cargo workspace and vscode sees the whole workspace.

If a change is made to the source of the builder crate vscode re-runs the builder on file save and changes in the generated code (in $OUT_DIR) appear as expected.

As far as I can tell, everything is working as expected except that warnings and errors from build.rs don't show up in the Problems view of vscode, even if build.rs panics vscode does not display any error or warning.

I am on the latest stable versions of rust, cargo and the vscode rust analyser extension.

I have tried making build.rs exit 0, exit non-zero and panic.

I have googled for known problems without success.

Does anyone have any idea what the problem is? Has anyone made errors from build.rs appear in the Problems view of vscode?