Add fe build --from-metadata to rebuild from a metadata.json input

CLI.md

@@ -94,6 +94,7 @@ Builds use the Sonatina codegen pipeline and generate EVM bytecode directly.
 
 ```
 fe build [--standalone] [--contract <name>] [--optimize <level>] [--out-dir <dir>] [--report [--report-out <out>] [--report-failed-only]] [path]
+fe build --from-metadata <PATH|-> [--contract <name>] [--optimize <level>] [--out-dir <dir>] [--emit <artifacts>]
 ```
 
 If `path` is omitted, it defaults to `.`.
@@ -234,6 +235,35 @@ Filenames are “sanitized” from contract names:
 
 This sanitization is also what the workspace collision check uses.
 
+### Rebuilding from metadata: `--from-metadata`
+
+`fe build --from-metadata <PATH|->` rebuilds a contract from a `<Contract>.metadata.json`
+recompilation input (as produced by `--emit metadata`) instead of a source tree. `-` reads the
+JSON from stdin, so external toolchains can pipe a synthesized metadata document into a single
+`fe build` invocation. All diagnostics go to stderr.
+
+Behavior:
+
+- The recorded project (all `sources`, one regenerated `fe.toml` per `settings.ingots[]` entry) is
+  materialized into a temporary directory and built through the normal ingot build path; the
+  bundled `std`/`core` are provided by the compiler.
+- **Contract selection**: defaults to the contract recorded in `settings.compilationTarget`;
+  `--contract <name>` overrides it.
+- **Optimizer level**: defaults to `settings.optimizer.level`; an explicit `-O`/`--optimize` wins,
+  with a warning on stderr that the rebuilt bytecode will not match the verified artifact.
+- **Arithmetic**: the per-ingot effective `arithmetic` values from the metadata are applied via
+  the regenerated `fe.toml` files (`dependency-arithmetic` is deliberately not re-applied; the
+  metadata records post-forcing values).
+- **Version check**: if `compiler.version` differs from the running compiler, a warning is printed
+  to stderr (no abort); exact bytecode reproduction is only guaranteed with the same version.
+- **Output**: artifacts are selected with `--emit` as usual and written to `--out-dir`, which
+  defaults to `./out` (relative to the current working directory, since there is no project
+  directory to anchor to).
+
+Errors (exit code 1): unreadable input, invalid JSON, `language != "Fe"`, missing `sources`, or a
+missing/rootless `settings.ingots`. Combining `--from-metadata` with the `[path]` argument,
+`--ingot`, `--standalone`, or `--report` is a CLI usage error (exit code 2).
+
 ### Reports: `--report`
 
 `fe build` can optionally write a `.tar.gz` debugging report (useful for sharing failures):

crates/common/src/file/workspace.rs

@@ -75,10 +75,7 @@ impl Workspace {
 
     #[salsa::tracked]
     pub fn get_relative_path(self, db: &dyn InputDb, base: Url, file: File) -> Option<Utf8PathBuf> {
-        let file_url = match self.paths(db).get(&file) {
-            Some(url) => url.clone(),
-            None => return None,
-        };
+        let file_url = self.get_path(db, file)?;
         base.make_relative(&file_url).map(Utf8PathBuf::from)
     }
 

crates/fe-web/src/model.rs

@@ -717,7 +717,7 @@ impl DocIndex {
                             // Look up the trait URL
                             let trait_url = lookup_trait(&trait_items, &trait_impl.trait_name)
                                 .map(|p| format!("{}/trait", p))
-                                .unwrap_or_else(|| format!("{}/trait", &trait_impl.trait_name));
+                                .unwrap_or_else(|| format!("{}/trait", trait_impl.trait_name));
 
                             // Use the target item's path and kind for the type URL
                             let type_url = format!("{}/{}", item.path, item.kind.as_str());

crates/fe/src/abi.rs

@@ -881,10 +881,9 @@ fn std_sol_compat_abi_type(
     // Match Uint{N} or Int{N} where N is a valid Solidity bit width (8..=256, multiple of 8)
     let (prefix, digits) = if let Some(rest) = name.strip_prefix("Uint") {
         ("uint", rest)
-    } else if let Some(rest) = name.strip_prefix("Int") {
-        ("int", rest)
     } else {
-        return None;
+        let rest = name.strip_prefix("Int")?;
+        ("int", rest)
     };
 
     let bits: u16 = digits.parse().ok()?;