Support "or patterns" MIR lowering

Author: HKalbasi

crates/hir-ty/src/consteval/tests.rs

@@ -559,11 +559,11 @@ fn function_param_patterns() {
     check_number(
         r#"
     const fn f(c @ (a, b): &(u8, u8)) -> u8 {
-        *a + *b + (*c).1
+        *a + *b + c.0 + (*c).1
     }
     const GOAL: u8 = f(&(2, 3));
         "#,
-        8,
+        10,
     );
     check_number(
         r#"
@@ -641,6 +641,44 @@ fn options() {
     );
 }
 
+#[test]
+fn or_pattern() {
+    check_number(
+        r#"
+    const GOAL: u8 = {
+        let (a | a) = 2;
+        a
+    };
+        "#,
+        2,
+    );
+    check_number(
+        r#"
+    //- minicore: option
+    const fn f(x: Option<i32>) -> i32 {
+        let (Some(a) | Some(a)) = x else { return 2; };
+        a
+    }
+    const GOAL: i32 = f(Some(10)) + f(None);
+        "#,
+        12,
+    );
+    check_number(
+        r#"
+    //- minicore: option
+    const fn f(x: Option<i32>, y: Option<i32>) -> i32 {
+        match (x, y) {
+            (Some(x), Some(y)) => x * y,
+            (Some(a), _) | (_, Some(a)) => a,
+            _ => 10,
+        }
+    }
+    const GOAL: i32 = f(Some(10), Some(20)) + f(Some(30), None) + f(None, Some(40)) + f(None, None);
+        "#,
+        280,
+    );
+}
+
 #[test]
 fn array_and_index() {
     check_number(

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

@@ -155,12 +155,7 @@ impl MirLowerCtx<'_> {
         if let Some(p) = self.lower_expr_as_place(expr_id) {
             return Ok((p, prev_block));
         }
-        let mut ty = self.expr_ty(expr_id);
-        if let Some(x) = self.infer.expr_adjustments.get(&expr_id) {
-            if let Some(x) = x.last() {
-                ty = x.target.clone();
-            }
-        }
+        let ty = self.expr_ty_after_adjustments(expr_id);
         let place = self.temp(ty)?;
         Ok((place.into(), self.lower_expr_to_place(expr_id, place.into(), prev_block)?))
     }
@@ -323,7 +318,7 @@ impl MirLowerCtx<'_> {
                     current,
                     None,
                     cond_place,
-                    self.expr_ty(*expr),
+                    self.expr_ty_after_adjustments(*expr),
                     *pat,
                     BindingAnnotation::Unannotated,
                 )?;
@@ -339,7 +334,53 @@ impl MirLowerCtx<'_> {
                 self.lower_block_to_place(None, statements, current, *tail, place)
             }
             Expr::Block { id: _, statements, tail, label } => {
-                self.lower_block_to_place(*label, statements, current, *tail, place)
+                if label.is_some() {
+                    not_supported!("block with label");
+                }
+                for statement in statements.iter() {
+                    match statement {
+                        hir_def::expr::Statement::Let {
+                            pat,
+                            initializer,
+                            else_branch,
+                            type_ref: _,
+                        } => match initializer {
+                            Some(expr_id) => {
+                                let else_block;
+                                let init_place;
+                                (init_place, current) =
+                                    self.lower_expr_to_some_place(*expr_id, current)?;
+                                (current, else_block) = self.pattern_match(
+                                    current,
+                                    None,
+                                    init_place,
+                                    self.expr_ty_after_adjustments(*expr_id),
+                                    *pat,
+                                    BindingAnnotation::Unannotated,
+                                )?;
+                                match (else_block, else_branch) {
+                                    (None, _) => (),
+                                    (Some(else_block), None) => {
+                                        self.set_terminator(else_block, Terminator::Unreachable);
+                                    }
+                                    (Some(else_block), Some(else_branch)) => {
+                                        let (_, b) = self
+                                            .lower_expr_to_some_place(*else_branch, else_block)?;
+                                        self.set_terminator(b, Terminator::Unreachable);
+                                    }
+                                }
+                            }
+                            None => continue,
+                        },
+                        hir_def::expr::Statement::Expr { expr, has_semi: _ } => {
+                            (_, current) = self.lower_expr_to_some_place(*expr, current)?;
+                        }
+                    }
+                }
+                match tail {
+                    Some(tail) => self.lower_expr_to_place(*tail, place, current),
+                    None => Ok(current),
+                }
             }
             Expr::Loop { body, label } => self.lower_loop(current, *label, |this, begin, _| {
                 let (_, block) = this.lower_expr_to_some_place(*body, begin)?;
@@ -364,7 +405,7 @@ impl MirLowerCtx<'_> {
             }
             Expr::For { .. } => not_supported!("for loop"),
             Expr::Call { callee, args, .. } => {
-                let callee_ty = self.expr_ty(*callee);
+                let callee_ty = self.expr_ty_after_adjustments(*callee);
                 match &callee_ty.data(Interner).kind {
                     chalk_ir::TyKind::FnDef(..) => {
                         let func = Operand::from_bytes(vec![], callee_ty.clone());
@@ -414,7 +455,7 @@ impl MirLowerCtx<'_> {
             }
             Expr::Match { expr, arms } => {
                 let (cond_place, mut current) = self.lower_expr_to_some_place(*expr, current)?;
-                let cond_ty = self.expr_ty(*expr);
+                let cond_ty = self.expr_ty_after_adjustments(*expr);
                 let end = self.new_basic_block();
                 for MatchArm { pat, guard, expr } in arms.iter() {
                     if guard.is_some() {
@@ -524,7 +565,7 @@ impl MirLowerCtx<'_> {
             }
             Expr::Field { expr, name } => {
                 let (mut current_place, current) = self.lower_expr_to_some_place(*expr, current)?;
-                if let TyKind::Tuple(..) = self.expr_ty(*expr).kind(Interner) {
+                if let TyKind::Tuple(..) = self.expr_ty_after_adjustments(*expr).kind(Interner) {
                     let index = name
                         .as_tuple_index()
                         .ok_or(MirLowerError::TypeError("named field on tuple"))?;
@@ -623,7 +664,7 @@ impl MirLowerCtx<'_> {
             Expr::Index { base, index } => {
                 let mut p_base;
                 (p_base, current) = self.lower_expr_to_some_place(*base, current)?;
-                let l_index = self.temp(self.expr_ty(*index))?;
+                let l_index = self.temp(self.expr_ty_after_adjustments(*index))?;
                 current = self.lower_expr_to_place(*index, l_index.into(), current)?;
                 p_base.projection.push(ProjectionElem::Index(l_index));
                 self.push_assignment(current, place, Operand::Copy(p_base).into());
@@ -878,6 +919,16 @@ impl MirLowerCtx<'_> {
         self.infer[e].clone()
     }
 
+    fn expr_ty_after_adjustments(&self, e: ExprId) -> Ty {
+        let mut ty = None;
+        if let Some(x) = self.infer.expr_adjustments.get(&e) {
+            if let Some(x) = x.last() {
+                ty = Some(x.target.clone());
+            }
+        }
+        ty.unwrap_or_else(|| self.expr_ty(e))
+    }
+
     fn push_assignment(&mut self, block: BasicBlockId, place: Place, rvalue: Rvalue) {
         self.result.basic_blocks[block].statements.push(Statement::Assign(place, rvalue));
     }
@@ -928,7 +979,25 @@ impl MirLowerCtx<'_> {
                     binding_mode,
                 )?
             }
-            Pat::Or(_) => not_supported!("or pattern"),
+            Pat::Or(pats) => {
+                let then_target = self.new_basic_block();
+                let mut finished = false;
+                for pat in &**pats {
+                    let (next, next_else) =
+                        self.pattern_match(current, None, cond_place.clone(), cond_ty.clone(), *pat, binding_mode)?;
+                    self.set_goto(next, then_target);
+                    match next_else {
+                        Some(t) => {
+                            current = t;
+                        }
+                        None => {
+                            finished = true;
+                            break;
+                        }
+                    }
+                }
+                (then_target, (!finished).then_some(current))
+            }
             Pat::Record { .. } => not_supported!("record pattern"),
             Pat::Range { .. } => not_supported!("range pattern"),
             Pat::Slice { .. } => not_supported!("slice pattern"),