Allow interpreting consts and statics with interpret function command

Author: Veykril

crates/hir-def/src/data.rs

@@ -37,6 +37,7 @@ pub struct FunctionData {
     pub name: Name,
     pub params: Box<[TypeRefId]>,
     pub ret_type: TypeRefId,
+    // FIXME: why are these stored here? They should be accessed via the query
     pub attrs: Attrs,
     pub visibility: RawVisibility,
     pub abi: Option<Symbol>,

crates/hir-ty/src/consteval.rs

@@ -56,6 +56,21 @@ pub enum ConstEvalError {
     MirEvalError(MirEvalError),
 }
 
+impl ConstEvalError {
+    pub fn pretty_print(
+        &self,
+        f: &mut String,
+        db: &dyn HirDatabase,
+        span_formatter: impl Fn(span::FileId, span::TextRange) -> String,
+        edition: span::Edition,
+    ) -> std::result::Result<(), std::fmt::Error> {
+        match self {
+            ConstEvalError::MirLowerError(e) => e.pretty_print(f, db, span_formatter, edition),
+            ConstEvalError::MirEvalError(e) => e.pretty_print(f, db, span_formatter, edition),
+        }
+    }
+}
+
 impl From<MirLowerError> for ConstEvalError {
     fn from(value: MirLowerError) -> Self {
         match value {
@@ -253,7 +268,7 @@ pub(crate) fn const_eval_query(
         }
         GeneralConstId::InTypeConstId(c) => db.mir_body(c.into())?,
     };
-    let c = interpret_mir(db, body, false, trait_env).0?;
+    let c = interpret_mir(db, body, false, trait_env)?.0?;
     Ok(c)
 }
 
@@ -266,7 +281,7 @@ pub(crate) fn const_eval_static_query(
         Substitution::empty(Interner),
         db.trait_environment_for_body(def.into()),
     )?;
-    let c = interpret_mir(db, body, false, None).0?;
+    let c = interpret_mir(db, body, false, None)?.0?;
     Ok(c)
 }
 
@@ -298,7 +313,7 @@ pub(crate) fn const_eval_discriminant_variant(
         Substitution::empty(Interner),
         db.trait_environment_for_body(def),
     )?;
-    let c = interpret_mir(db, mir_body, false, None).0?;
+    let c = interpret_mir(db, mir_body, false, None)?.0?;
     let c = if is_signed {
         try_const_isize(db, &c).unwrap()
     } else {
@@ -339,7 +354,7 @@ pub(crate) fn eval_to_const(
         }
     }
     if let Ok(mir_body) = lower_to_mir(ctx.db, ctx.owner, ctx.body, &infer, expr) {
-        if let Ok(result) = interpret_mir(db, Arc::new(mir_body), true, None).0 {
+        if let Ok((Ok(result), _)) = interpret_mir(db, Arc::new(mir_body), true, None) {
             return result;
         }
     }

crates/hir-ty/src/mir/eval.rs

@@ -585,13 +585,9 @@ pub fn interpret_mir(
     // (and probably should) do better here, for example by excluding bindings outside of the target expression.
     assert_placeholder_ty_is_unused: bool,
     trait_env: Option<Arc<TraitEnvironment>>,
-) -> (Result<Const>, MirOutput) {
+) -> Result<(Result<Const>, MirOutput)> {
     let ty = body.locals[return_slot()].ty.clone();
-    let mut evaluator =
-        match Evaluator::new(db, body.owner, assert_placeholder_ty_is_unused, trait_env) {
-            Ok(it) => it,
-            Err(e) => return (Err(e), MirOutput { stdout: vec![], stderr: vec![] }),
-        };
+    let mut evaluator = Evaluator::new(db, body.owner, assert_placeholder_ty_is_unused, trait_env)?;
     let it: Result<Const> = (|| {
         if evaluator.ptr_size() != std::mem::size_of::<usize>() {
             not_supported!("targets with different pointer size from host");
@@ -613,7 +609,7 @@ pub fn interpret_mir(
         };
         Ok(intern_const_scalar(ConstScalar::Bytes(bytes, memory_map), ty))
     })();
-    (it, MirOutput { stdout: evaluator.stdout, stderr: evaluator.stderr })
+    Ok((it, MirOutput { stdout: evaluator.stdout, stderr: evaluator.stderr }))
 }
 
 #[cfg(test)]

crates/hir-ty/src/mir/eval/tests.rs

@@ -32,7 +32,7 @@ fn eval_main(db: &TestDB, file_id: EditionedFileId) -> Result<(String, String),
         )
         .map_err(|e| MirEvalError::MirLowerError(func_id, e))?;
 
-    let (result, output) = interpret_mir(db, body, false, None);
+    let (result, output) = interpret_mir(db, body, false, None)?;
     result?;
     Ok((output.stdout().into_owned(), output.stderr().into_owned()))
 }

crates/hir/src/lib.rs

@@ -2306,22 +2306,15 @@ impl Function {
         self,
         db: &dyn HirDatabase,
         span_formatter: impl Fn(FileId, TextRange) -> String,
-    ) -> String {
+    ) -> Result<String, ConstEvalError> {
         let krate = HasModule::krate(&self.id, db.upcast());
         let edition = db.crate_graph()[krate].edition;
-        let body = match db.monomorphized_mir_body(
+        let body = db.monomorphized_mir_body(
             self.id.into(),
             Substitution::empty(Interner),
             db.trait_environment(self.id.into()),
-        ) {
-            Ok(body) => body,
-            Err(e) => {
-                let mut r = String::new();
-                _ = e.pretty_print(&mut r, db, &span_formatter, edition);
-                return r;
-            }
-        };
-        let (result, output) = interpret_mir(db, body, false, None);
+        )?;
+        let (result, output) = interpret_mir(db, body, false, None)?;
         let mut text = match result {
             Ok(_) => "pass".to_owned(),
             Err(e) => {
@@ -2340,7 +2333,7 @@ impl Function {
             text += "\n--------- stderr ---------\n";
             text += &stderr;
         }
-        text
+        Ok(text)
     }
 }
 
@@ -2563,9 +2556,9 @@ impl Const {
     /// Evaluate the constant and return the result as a string.
     ///
     /// This function is intended for IDE assistance, different from [`Const::render_eval`].
-    pub fn eval(self, db: &dyn HirDatabase, edition: Edition) -> Result<String, ConstEvalError> {
+    pub fn eval(self, db: &dyn HirDatabase) -> Result<String, ConstEvalError> {
         let c = db.const_eval(self.id.into(), Substitution::empty(Interner), None)?;
-        Ok(format!("{}", c.display(db, edition)))
+        Ok(format!("{}", c.display(db, self.krate(db).edition(db))))
     }
 
     /// Evaluate the constant and return the result as a string, with more detailed information.
@@ -2640,7 +2633,15 @@ impl Static {
         Type::from_value_def(db, self.id)
     }
 
-    /// Evaluate the constant and return the result as a string, with more detailed information.
+    /// Evaluate the static and return the result as a string.
+    ///
+    /// This function is intended for IDE assistance, different from [`Static::render_eval`].
+    pub fn eval(self, db: &dyn HirDatabase) -> Result<String, ConstEvalError> {
+        let c = db.const_eval(self.id.into(), Substitution::empty(Interner), None)?;
+        Ok(format!("{}", c.display(db, self.krate(db).edition(db))))
+    }
+
+    /// Evaluate the static and return the result as a string, with more detailed information.
     ///
     /// This function is intended for user-facing display.
     pub fn render_eval(

crates/ide-assists/src/handlers/inline_const_as_literal.rs

@@ -51,10 +51,7 @@ pub(crate) fn inline_const_as_literal(acc: &mut Assists, ctx: &AssistContext<'_>
             | ast::Expr::MatchExpr(_)
             | ast::Expr::MacroExpr(_)
             | ast::Expr::BinExpr(_)
-            | ast::Expr::CallExpr(_) => {
-                let edition = ctx.sema.scope(variable.syntax())?.krate().edition(ctx.db());
-                konst.eval(ctx.sema.db, edition).ok()?
-            }
+            | ast::Expr::CallExpr(_) => konst.eval(ctx.sema.db).ok()?,
             _ => return None,
         };
 

crates/ide/src/interpret.rs

@@ -0,0 +1,64 @@
+use hir::{DefWithBody, Semantics};
+use ide_db::{base_db::SourceRootDatabase, FilePosition, LineIndexDatabase, RootDatabase};
+use std::time::{Duration, Instant};
+use stdx::format_to;
+use syntax::{algo::ancestors_at_offset, ast, AstNode, TextRange};
+
+// Feature: Interpret a function, static or const.
+//
+// |===
+// | Editor  | Action Name
+//
+// | VS Code | **rust-analyzer: Interpret**
+// |===
+pub(crate) fn interpret(db: &RootDatabase, position: FilePosition) -> String {
+    match find_and_interpret(db, position) {
+        Some((duration, mut result)) => {
+            result.push('\n');
+            format_to!(result, "----------------------\n");
+            format_to!(result, "  Finished in {}s\n", duration.as_secs_f32());
+            result
+        }
+        _ => "Not inside a function, const or static".to_owned(),
+    }
+}
+
+fn find_and_interpret(db: &RootDatabase, position: FilePosition) -> Option<(Duration, String)> {
+    let sema = Semantics::new(db);
+    let source_file = sema.parse_guess_edition(position.file_id);
+
+    let item = ancestors_at_offset(source_file.syntax(), position.offset)
+        .filter(|it| !ast::MacroCall::can_cast(it.kind()))
+        .find_map(ast::Item::cast)?;
+    let def: DefWithBody = match item {
+        ast::Item::Fn(it) => sema.to_def(&it)?.into(),
+        ast::Item::Const(it) => sema.to_def(&it)?.into(),
+        ast::Item::Static(it) => sema.to_def(&it)?.into(),
+        _ => return None,
+    };
+    let span_formatter = |file_id, text_range: TextRange| {
+        let path = &db
+            .source_root(db.file_source_root(file_id))
+            .path_for_file(&file_id)
+            .map(|x| x.to_string());
+        let path = path.as_deref().unwrap_or("<unknown file>");
+        match db.line_index(file_id).try_line_col(text_range.start()) {
+            Some(line_col) => format!("file://{path}:{}:{}", line_col.line + 1, line_col.col),
+            None => format!("file://{path} range {text_range:?}"),
+        }
+    };
+    let start_time = Instant::now();
+    let res = match def {
+        DefWithBody::Function(it) => it.eval(db, span_formatter),
+        DefWithBody::Static(it) => it.eval(db),
+        DefWithBody::Const(it) => it.eval(db),
+        _ => unreachable!(),
+    };
+    let res = res.unwrap_or_else(|e| {
+        let mut r = String::new();
+        _ = e.pretty_print(&mut r, db, span_formatter, def.module(db).krate().edition(db));
+        r
+    });
+    let duration = Instant::now() - start_time;
+    Some((duration, res))
+}

crates/ide/src/interpret_function.rs

@@ -33,7 +33,7 @@ mod goto_type_definition;
 mod highlight_related;
 mod hover;
 mod inlay_hints;
-mod interpret_function;
+mod interpret;
 mod join_lines;
 mod markdown_remove;
 mod matching_brace;
@@ -350,7 +350,7 @@ impl Analysis {
     }
 
     pub fn interpret_function(&self, position: FilePosition) -> Cancellable<String> {
-        self.with_db(|db| interpret_function::interpret_function(db, position))
+        self.with_db(|db| interpret::interpret(db, position))
     }
 
     pub fn view_item_tree(&self, file_id: FileId) -> Cancellable<String> {

crates/ide/src/lib.rs

@@ -398,6 +398,8 @@ define_symbols! {
     rustc_const_panic_str,
     rustc_deprecated_safe_2024,
     rustc_has_incoherent_inherent_impls,
+    rustc_intrinsic,
+    rustc_intrinsic_must_be_overridden,
     rustc_layout_scalar_valid_range_end,
     rustc_layout_scalar_valid_range_start,
     rustc_legacy_const_generics,