rustviz-plugin

The compiler-integrated heart of RustViz. A rustc_private plugin that walks HIR/MIR for a single-file crate and emits a code panel + timeline panel as SVGs on stdout. Built on Will Crichton's rustc_plugin / rustc_utils crates (same family as Flowistry / Aquascope).

End users typically don't touch this crate directly — they use one of:

• the rustviz CLI in rustviz-cli (rustviz svg foo.rs, rustviz html foo.rs),
• the mdbook-rustviz preprocessor in mdbook-rustviz (```rv fenced blocks),
• the playground in ../playground/, or
• the rustviz-lib Rust library in rustviz-lib.

Each of those routes calls into the binaries this crate produces (cargo-rv-plugin, rv-plugin-driver).

Installing

The standard install path is via the rustviz CLI's bootstrap, which also installs the matching nightly toolchain:

cargo install rustviz-cli
rustviz init

To install from source against a local checkout:

rustup toolchain install nightly-2025-08-20 \
    --profile minimal \
    --component rust-src,rustc-dev,llvm-tools-preview
cargo install --path . --locked

Limitations

RustViz is a teaching tool — it supports a meaningful subset of Rust, not all of it. Currently unsupported (or known to misbehave):

• For-loops
• Conditional let bindings
• Borrows that occur inside conditionals
• Some borrows over struct members
• Lifetime annotations beyond what the Excerpt<'a> tutorial example covers

To fix / implement

• Handle owners that are declared inside conditional blocks
• Typecheck function ctxt to determine what type of return annotation to make
• Implement new state calculation system
• Remove struct members that are not utilized from the timeline
• Implement hoverable anonymous owner interactions in code panel
• Weird phantom annotated src bug that seems to appear when there are \t characters
• Add highlighting for passbyref events
• Implement For-loops (really just desugared match expr)
• last (black) data-hash doesn't render properly
• Fix resource dropping (breaks with conditionals)
• Reference aliasing
• Fix annotated source gen to handle < / > characters
• Let-if / match expressions (new conditional move event)
• Conditional lifetime logic and visualization
• Bad stuff happens when you don't put a semi-colon at the end of a void stmt at the end of a block
• Chained method calls (goes hand in hand with anonymous owner interactions, e.g. .get().get_mut())
• Lifetimes that are 'captured' by conditional statements (use MIR)
• Struct box kind of buggy
• JSONify the output