1 files changed, 205 insertions, 0 deletions

diff --git a/crates/hir_ty/src/diagnostics/unsafe_check.rs b/crates/hir_ty/src/diagnostics/unsafe_check.rs
new file mode 100644
index 000000000..61ffbf5d1
--- /dev/null
+++ b/crates/hir_ty/src/diagnostics/unsafe_check.rs
@@ -0,0 +1,205 @@
+//! Provides validations for unsafe code. Currently checks if unsafe functions are missing
+//! unsafe blocks.
+
+use std::sync::Arc;
+
+use hir_def::{
+    body::Body,
+    expr::{Expr, ExprId, UnaryOp},
+    resolver::{resolver_for_expr, ResolveValueResult, ValueNs},
+    DefWithBodyId,
+};
+use hir_expand::diagnostics::DiagnosticSink;
+
+use crate::{
+    db::HirDatabase, diagnostics::MissingUnsafe, lower::CallableDefId, ApplicationTy,
+    InferenceResult, Ty, TypeCtor,
+};
+
+pub(super) struct UnsafeValidator<'a, 'b: 'a> {
+    owner: DefWithBodyId,
+    infer: Arc<InferenceResult>,
+    sink: &'a mut DiagnosticSink<'b>,
+}
+
+impl<'a, 'b> UnsafeValidator<'a, 'b> {
+    pub(super) fn new(
+        owner: DefWithBodyId,
+        infer: Arc<InferenceResult>,
+        sink: &'a mut DiagnosticSink<'b>,
+    ) -> UnsafeValidator<'a, 'b> {
+        UnsafeValidator { owner, infer, sink }
+    }
+
+    pub(super) fn validate_body(&mut self, db: &dyn HirDatabase) {
+        let def = self.owner.into();
+        let unsafe_expressions = unsafe_expressions(db, self.infer.as_ref(), def);
+        let is_unsafe = match self.owner {
+            DefWithBodyId::FunctionId(it) => db.function_data(it).is_unsafe,
+            DefWithBodyId::StaticId(_) | DefWithBodyId::ConstId(_) => false,
+        };
+        if is_unsafe
+            || unsafe_expressions
+                .iter()
+                .filter(|unsafe_expr| !unsafe_expr.inside_unsafe_block)
+                .count()
+                == 0
+        {
+            return;
+        }
+
+        let (_, body_source) = db.body_with_source_map(def);
+        for unsafe_expr in unsafe_expressions {
+            if !unsafe_expr.inside_unsafe_block {
+                if let Ok(in_file) = body_source.as_ref().expr_syntax(unsafe_expr.expr) {
+                    self.sink.push(MissingUnsafe { file: in_file.file_id, expr: in_file.value })
+                }
+            }
+        }
+    }
+}
+
+pub struct UnsafeExpr {
+    pub expr: ExprId,
+    pub inside_unsafe_block: bool,
+}
+
+pub fn unsafe_expressions(
+    db: &dyn HirDatabase,
+    infer: &InferenceResult,
+    def: DefWithBodyId,
+) -> Vec<UnsafeExpr> {
+    let mut unsafe_exprs = vec![];
+    let body = db.body(def);
+    walk_unsafe(&mut unsafe_exprs, db, infer, def, &body, body.body_expr, false);
+
+    unsafe_exprs
+}
+
+fn walk_unsafe(
+    unsafe_exprs: &mut Vec<UnsafeExpr>,
+    db: &dyn HirDatabase,
+    infer: &InferenceResult,
+    def: DefWithBodyId,
+    body: &Body,
+    current: ExprId,
+    inside_unsafe_block: bool,
+) {
+    let expr = &body.exprs[current];
+    match expr {
+        Expr::Call { callee, .. } => {
+            let ty = &infer[*callee];
+            if let &Ty::Apply(ApplicationTy {
+                ctor: TypeCtor::FnDef(CallableDefId::FunctionId(func)),
+                ..
+            }) = ty
+            {
+                if db.function_data(func).is_unsafe {
+                    unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block });
+                }
+            }
+        }
+        Expr::Path(path) => {
+            let resolver = resolver_for_expr(db.upcast(), def, current);
+            let value_or_partial = resolver.resolve_path_in_value_ns(db.upcast(), path.mod_path());
+            if let Some(ResolveValueResult::ValueNs(ValueNs::StaticId(id))) = value_or_partial {
+                if db.static_data(id).mutable {
+                    unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block });
+                }
+            }
+        }
+        Expr::MethodCall { .. } => {
+            if infer
+                .method_resolution(current)
+                .map(|func| db.function_data(func).is_unsafe)
+                .unwrap_or(false)
+            {
+                unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block });
+            }
+        }
+        Expr::UnaryOp { expr, op: UnaryOp::Deref } => {
+            if let Ty::Apply(ApplicationTy { ctor: TypeCtor::RawPtr(..), .. }) = &infer[*expr] {
+                unsafe_exprs.push(UnsafeExpr { expr: current, inside_unsafe_block });
+            }
+        }
+        Expr::Unsafe { body: child } => {
+            return walk_unsafe(unsafe_exprs, db, infer, def, body, *child, true);
+        }
+        _ => {}
+    }
+
+    expr.walk_child_exprs(|child| {
+        walk_unsafe(unsafe_exprs, db, infer, def, body, child, inside_unsafe_block);
+    });
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::check_diagnostics;
+
+    #[test]
+    fn missing_unsafe_diagnostic_with_raw_ptr() {
+        check_diagnostics(
+            r#"
+fn main() {
+    let x = &5 as *const usize;
+    unsafe { let y = *x; }
+    let z = *x;
+}         //^^ This operation is unsafe and requires an unsafe function or block
+"#,
+        )
+    }
+
+    #[test]
+    fn missing_unsafe_diagnostic_with_unsafe_call() {
+        check_diagnostics(
+            r#"
+struct HasUnsafe;
+
+impl HasUnsafe {
+    unsafe fn unsafe_fn(&self) {
+        let x = &5 as *const usize;
+        let y = *x;
+    }
+}
+
+unsafe fn unsafe_fn() {
+    let x = &5 as *const usize;
+    let y = *x;
+}
+
+fn main() {
+    unsafe_fn();
+  //^^^^^^^^^^^ This operation is unsafe and requires an unsafe function or block
+    HasUnsafe.unsafe_fn();
+  //^^^^^^^^^^^^^^^^^^^^^ This operation is unsafe and requires an unsafe function or block
+    unsafe {
+        unsafe_fn();
+        HasUnsafe.unsafe_fn();
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn missing_unsafe_diagnostic_with_static_mut() {
+        check_diagnostics(
+            r#"
+struct Ty {
+    a: u8,
+}
+
+static mut static_mut: Ty = Ty { a: 0 };
+
+fn main() {
+    let x = static_mut.a;
+          //^^^^^^^^^^ This operation is unsafe and requires an unsafe function or block
+    unsafe {
+        let x = static_mut.a;
+    }
+}
+"#,
+        );
+    }
+}