Merge #8457

8457: Implement more precise binary op return type heuristic r=flodiebold a=Veykril

Should fix #7150

Co-authored-by: Lukas Wirth <[email protected]>

Author: bors[bot]

crates/hir_ty/src/op.rs

@@ -9,21 +9,55 @@ pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
         BinaryOp::LogicOp(_) | BinaryOp::CmpOp(_) => TyKind::Scalar(Scalar::Bool).intern(&Interner),
         BinaryOp::Assignment { .. } => TyBuilder::unit(),
         BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => {
-            match lhs_ty.kind(&Interner) {
+            // all integer combinations are valid here
+            if matches!(
+                lhs_ty.kind(&Interner),
                 TyKind::Scalar(Scalar::Int(_))
-                | TyKind::Scalar(Scalar::Uint(_))
-                | TyKind::Scalar(Scalar::Float(_)) => lhs_ty,
-                TyKind::InferenceVar(_, TyVariableKind::Integer)
-                | TyKind::InferenceVar(_, TyVariableKind::Float) => lhs_ty,
-                _ => TyKind::Error.intern(&Interner),
+                    | TyKind::Scalar(Scalar::Uint(_))
+                    | TyKind::InferenceVar(_, TyVariableKind::Integer)
+            ) && matches!(
+                rhs_ty.kind(&Interner),
+                TyKind::Scalar(Scalar::Int(_))
+                    | TyKind::Scalar(Scalar::Uint(_))
+                    | TyKind::InferenceVar(_, TyVariableKind::Integer)
+            ) {
+                lhs_ty
+            } else {
+                TyKind::Error.intern(&Interner)
             }
         }
-        BinaryOp::ArithOp(_) => match rhs_ty.kind(&Interner) {
-            TyKind::Scalar(Scalar::Int(_))
-            | TyKind::Scalar(Scalar::Uint(_))
-            | TyKind::Scalar(Scalar::Float(_)) => rhs_ty,
-            TyKind::InferenceVar(_, TyVariableKind::Integer)
-            | TyKind::InferenceVar(_, TyVariableKind::Float) => rhs_ty,
+        BinaryOp::ArithOp(_) => match (lhs_ty.kind(&Interner), rhs_ty.kind(&Interner)) {
+            // (int, int) | (uint, uint) | (float, float)
+            (TyKind::Scalar(Scalar::Int(_)), TyKind::Scalar(Scalar::Int(_)))
+            | (TyKind::Scalar(Scalar::Uint(_)), TyKind::Scalar(Scalar::Uint(_)))
+            | (TyKind::Scalar(Scalar::Float(_)), TyKind::Scalar(Scalar::Float(_))) => rhs_ty,
+            // ({int}, int) | ({int}, uint)
+            (TyKind::InferenceVar(_, TyVariableKind::Integer), TyKind::Scalar(Scalar::Int(_)))
+            | (TyKind::InferenceVar(_, TyVariableKind::Integer), TyKind::Scalar(Scalar::Uint(_))) => {
+                rhs_ty
+            }
+            // (int, {int}) | (uint, {int})
+            (TyKind::Scalar(Scalar::Int(_)), TyKind::InferenceVar(_, TyVariableKind::Integer))
+            | (TyKind::Scalar(Scalar::Uint(_)), TyKind::InferenceVar(_, TyVariableKind::Integer)) => {
+                lhs_ty
+            }
+            // ({float} | float)
+            (TyKind::InferenceVar(_, TyVariableKind::Float), TyKind::Scalar(Scalar::Float(_))) => {
+                rhs_ty
+            }
+            // (float, {float})
+            (TyKind::Scalar(Scalar::Float(_)), TyKind::InferenceVar(_, TyVariableKind::Float)) => {
+                lhs_ty
+            }
+            // ({int}, {int}) | ({float}, {float})
+            (
+                TyKind::InferenceVar(_, TyVariableKind::Integer),
+                TyKind::InferenceVar(_, TyVariableKind::Integer),
+            )
+            | (
+                TyKind::InferenceVar(_, TyVariableKind::Float),
+                TyKind::InferenceVar(_, TyVariableKind::Float),
+            ) => rhs_ty,
             _ => TyKind::Error.intern(&Interner),
         },
     }

crates/hir_ty/src/tests/traits.rs

@@ -1919,10 +1919,26 @@ fn closure_1() {
 fn closure_2() {
     check_infer_with_mismatches(
         r#"
+        #[lang = "add"]
+        pub trait Add<Rhs = Self> {
+            type Output;
+            fn add(self, rhs: Rhs) -> Self::Output;
+        }
+
         trait FnOnce<Args> {
             type Output;
         }
 
+        impl Add for u64 {
+            type Output = Self;
+            fn add(self, rhs: u64) -> Self::Output {0}
+        }
+
+        impl Add for u128 {
+            type Output = Self;
+            fn add(self, rhs: u128) -> Self::Output {0}
+        }
+
         fn test<F: FnOnce(u32) -> u64>(f: F) {
             f(1);
             let g = |v| v + 1;
@@ -1931,26 +1947,36 @@ fn closure_2() {
         }
         "#,
         expect![[r#"
-            72..73 'f': F
-            78..154 '{     ...+ v; }': ()
-            84..85 'f': F
-            84..88 'f(1)': {unknown}
-            86..87 '1': i32
-            98..99 'g': |u64| -> i32
-            102..111 '|v| v + 1': |u64| -> i32
-            103..104 'v': u64
-            106..107 'v': u64
-            106..111 'v + 1': i32
-            110..111 '1': i32
-            117..118 'g': |u64| -> i32
-            117..124 'g(1u64)': i32
-            119..123 '1u64': u64
-            134..135 'h': |u128| -> u128
-            138..151 '|v| 1u128 + v': |u128| -> u128
-            139..140 'v': u128
-            142..147 '1u128': u128
-            142..151 '1u128 + v': u128
-            150..151 'v': u128
+            72..76 'self': Self
+            78..81 'rhs': Rhs
+            203..207 'self': u64
+            209..212 'rhs': u64
+            235..238 '{0}': u64
+            236..237 '0': u64
+            297..301 'self': u128
+            303..306 'rhs': u128
+            330..333 '{0}': u128
+            331..332 '0': u128
+            368..369 'f': F
+            374..450 '{     ...+ v; }': ()
+            380..381 'f': F
+            380..384 'f(1)': {unknown}
+            382..383 '1': i32
+            394..395 'g': |u64| -> u64
+            398..407 '|v| v + 1': |u64| -> u64
+            399..400 'v': u64
+            402..403 'v': u64
+            402..407 'v + 1': u64
+            406..407 '1': u64
+            413..414 'g': |u64| -> u64
+            413..420 'g(1u64)': u64
+            415..419 '1u64': u64
+            430..431 'h': |u128| -> u128
+            434..447 '|v| 1u128 + v': |u128| -> u128
+            435..436 'v': u128
+            438..443 '1u128': u128
+            438..447 '1u128 + v': u128
+            446..447 'v': u128
         "#]],
     );
 }
@@ -3443,3 +3469,50 @@ pub trait Deserialize {
     "#,
     );
 }
+
+#[test]
+fn bin_op_adt_with_rhs_primitive() {
+    check_infer_with_mismatches(
+        r#"
+#[lang = "add"]
+pub trait Add<Rhs = Self> {
+    type Output;
+    fn add(self, rhs: Rhs) -> Self::Output;
+}
+
+struct Wrapper(u32);
+impl Add<u32> for Wrapper {
+    type Output = Self;
+    fn add(self, rhs: u32) -> Wrapper {
+        Wrapper(rhs)
+    }
+}
+fn main(){
+    let wrapped = Wrapper(10);
+    let num: u32 = 2;
+    let res = wrapped + num;
+
+}"#,
+        expect![[r#"
+            72..76 'self': Self
+            78..81 'rhs': Rhs
+            192..196 'self': Wrapper
+            198..201 'rhs': u32
+            219..247 '{     ...     }': Wrapper
+            229..236 'Wrapper': Wrapper(u32) -> Wrapper
+            229..241 'Wrapper(rhs)': Wrapper
+            237..240 'rhs': u32
+            259..345 '{     ...um;  }': ()
+            269..276 'wrapped': Wrapper
+            279..286 'Wrapper': Wrapper(u32) -> Wrapper
+            279..290 'Wrapper(10)': Wrapper
+            287..289 '10': u32
+            300..303 'num': u32
+            311..312 '2': u32
+            322..325 'res': Wrapper
+            328..335 'wrapped': Wrapper
+            328..341 'wrapped + num': Wrapper
+            338..341 'num': u32
+        "#]],
+    )
+}