1 files changed, 656 insertions, 0 deletions

diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
new file mode 100644
index 000000000..39fabf7eb
--- /dev/null
+++ b/crates/hir_ty/src/tests/patterns.rs
@@ -0,0 +1,656 @@
+use expect::expect;
+use test_utils::mark;
+
+use super::{check_infer, check_infer_with_mismatches};
+
+#[test]
+fn infer_pattern() {
+    check_infer(
+        r#"
+        fn test(x: &i32) {
+            let y = x;
+            let &z = x;
+            let a = z;
+            let (c, d) = (1, "hello");
+
+            for (e, f) in some_iter {
+                let g = e;
+            }
+
+            if let [val] = opt {
+                let h = val;
+            }
+
+            let lambda = |a: u64, b, c: i32| { a + b; c };
+
+            let ref ref_to_x = x;
+            let mut mut_x = x;
+            let ref mut mut_ref_to_x = x;
+            let k = mut_ref_to_x;
+        }
+        "#,
+        expect![[r#"
+            8..9 'x': &i32
+            17..368 '{     ...o_x; }': ()
+            27..28 'y': &i32
+            31..32 'x': &i32
+            42..44 '&z': &i32
+            43..44 'z': i32
+            47..48 'x': &i32
+            58..59 'a': i32
+            62..63 'z': i32
+            73..79 '(c, d)': (i32, &str)
+            74..75 'c': i32
+            77..78 'd': &str
+            82..94 '(1, "hello")': (i32, &str)
+            83..84 '1': i32
+            86..93 '"hello"': &str
+            101..151 'for (e...     }': ()
+            105..111 '(e, f)': ({unknown}, {unknown})
+            106..107 'e': {unknown}
+            109..110 'f': {unknown}
+            115..124 'some_iter': {unknown}
+            125..151 '{     ...     }': ()
+            139..140 'g': {unknown}
+            143..144 'e': {unknown}
+            157..204 'if let...     }': ()
+            164..169 '[val]': [{unknown}]
+            165..168 'val': {unknown}
+            172..175 'opt': [{unknown}]
+            176..204 '{     ...     }': ()
+            190..191 'h': {unknown}
+            194..197 'val': {unknown}
+            214..220 'lambda': |u64, u64, i32| -> i32
+            223..255 '|a: u6...b; c }': |u64, u64, i32| -> i32
+            224..225 'a': u64
+            232..233 'b': u64
+            235..236 'c': i32
+            243..255 '{ a + b; c }': i32
+            245..246 'a': u64
+            245..250 'a + b': u64
+            249..250 'b': u64
+            252..253 'c': i32
+            266..278 'ref ref_to_x': &&i32
+            281..282 'x': &i32
+            292..301 'mut mut_x': &i32
+            304..305 'x': &i32
+            315..335 'ref mu...f_to_x': &mut &i32
+            338..339 'x': &i32
+            349..350 'k': &mut &i32
+            353..365 'mut_ref_to_x': &mut &i32
+        "#]],
+    );
+}
+
+#[test]
+fn infer_literal_pattern() {
+    check_infer_with_mismatches(
+        r#"
+        fn any<T>() -> T { loop {} }
+        fn test(x: &i32) {
+            if let "foo" = any() {}
+            if let 1 = any() {}
+            if let 1u32 = any() {}
+            if let 1f32 = any() {}
+            if let 1.0 = any() {}
+            if let true = any() {}
+        }
+        "#,
+        expect![[r#"
+            17..28 '{ loop {} }': T
+            19..26 'loop {}': !
+            24..26 '{}': ()
+            37..38 'x': &i32
+            46..208 '{     ...) {} }': ()
+            52..75 'if let...y() {}': ()
+            59..64 '"foo"': &str
+            59..64 '"foo"': &str
+            67..70 'any': fn any<&str>() -> &str
+            67..72 'any()': &str
+            73..75 '{}': ()
+            80..99 'if let...y() {}': ()
+            87..88 '1': i32
+            87..88 '1': i32
+            91..94 'any': fn any<i32>() -> i32
+            91..96 'any()': i32
+            97..99 '{}': ()
+            104..126 'if let...y() {}': ()
+            111..115 '1u32': u32
+            111..115 '1u32': u32
+            118..121 'any': fn any<u32>() -> u32
+            118..123 'any()': u32
+            124..126 '{}': ()
+            131..153 'if let...y() {}': ()
+            138..142 '1f32': f32
+            138..142 '1f32': f32
+            145..148 'any': fn any<f32>() -> f32
+            145..150 'any()': f32
+            151..153 '{}': ()
+            158..179 'if let...y() {}': ()
+            165..168 '1.0': f64
+            165..168 '1.0': f64
+            171..174 'any': fn any<f64>() -> f64
+            171..176 'any()': f64
+            177..179 '{}': ()
+            184..206 'if let...y() {}': ()
+            191..195 'true': bool
+            191..195 'true': bool
+            198..201 'any': fn any<bool>() -> bool
+            198..203 'any()': bool
+            204..206 '{}': ()
+        "#]],
+    );
+}
+
+#[test]
+fn infer_range_pattern() {
+    check_infer_with_mismatches(
+        r#"
+        fn test(x: &i32) {
+            if let 1..76 = 2u32 {}
+            if let 1..=76 = 2u32 {}
+        }
+        "#,
+        expect![[r#"
+            8..9 'x': &i32
+            17..75 '{     ...2 {} }': ()
+            23..45 'if let...u32 {}': ()
+            30..35 '1..76': u32
+            38..42 '2u32': u32
+            43..45 '{}': ()
+            50..73 'if let...u32 {}': ()
+            57..63 '1..=76': u32
+            66..70 '2u32': u32
+            71..73 '{}': ()
+        "#]],
+    );
+}
+
+#[test]
+fn infer_pattern_match_ergonomics() {
+    check_infer(
+        r#"
+        struct A<T>(T);
+
+        fn test() {
+            let A(n) = &A(1);
+            let A(n) = &mut A(1);
+        }
+        "#,
+        expect![[r#"
+            27..78 '{     ...(1); }': ()
+            37..41 'A(n)': A<i32>
+            39..40 'n': &i32
+            44..49 '&A(1)': &A<i32>
+            45..46 'A': A<i32>(i32) -> A<i32>
+            45..49 'A(1)': A<i32>
+            47..48 '1': i32
+            59..63 'A(n)': A<i32>
+            61..62 'n': &mut i32
+            66..75 '&mut A(1)': &mut A<i32>
+            71..72 'A': A<i32>(i32) -> A<i32>
+            71..75 'A(1)': A<i32>
+            73..74 '1': i32
+        "#]],
+    );
+}
+
+#[test]
+fn infer_pattern_match_ergonomics_ref() {
+    mark::check!(match_ergonomics_ref);
+    check_infer(
+        r#"
+        fn test() {
+            let v = &(1, &2);
+            let (_, &w) = v;
+        }
+        "#,
+        expect![[r#"
+            10..56 '{     ...= v; }': ()
+            20..21 'v': &(i32, &i32)
+            24..32 '&(1, &2)': &(i32, &i32)
+            25..32 '(1, &2)': (i32, &i32)
+            26..27 '1': i32
+            29..31 '&2': &i32
+            30..31 '2': i32
+            42..49 '(_, &w)': (i32, &i32)
+            43..44 '_': i32
+            46..48 '&w': &i32
+            47..48 'w': i32
+            52..53 'v': &(i32, &i32)
+        "#]],
+    );
+}
+
+#[test]
+fn infer_pattern_match_slice() {
+    check_infer(
+        r#"
+        fn test() {
+            let slice: &[f64] = &[0.0];
+            match slice {
+                &[] => {},
+                &[a] => {
+                    a;
+                },
+                &[b, c] => {
+                    b;
+                    c;
+                }
+                _ => {}
+            }
+        }
+        "#,
+        expect![[r#"
+            10..209 '{     ...   } }': ()
+            20..25 'slice': &[f64]
+            36..42 '&[0.0]': &[f64; _]
+            37..42 '[0.0]': [f64; _]
+            38..41 '0.0': f64
+            48..207 'match ...     }': ()
+            54..59 'slice': &[f64]
+            70..73 '&[]': &[f64]
+            71..73 '[]': [f64]
+            77..79 '{}': ()
+            89..93 '&[a]': &[f64]
+            90..93 '[a]': [f64]
+            91..92 'a': f64
+            97..123 '{     ...     }': ()
+            111..112 'a': f64
+            133..140 '&[b, c]': &[f64]
+            134..140 '[b, c]': [f64]
+            135..136 'b': f64
+            138..139 'c': f64
+            144..185 '{     ...     }': ()
+            158..159 'b': f64
+            173..174 'c': f64
+            194..195 '_': &[f64]
+            199..201 '{}': ()
+        "#]],
+    );
+}
+
+#[test]
+fn infer_pattern_match_string_literal() {
+    check_infer_with_mismatches(
+        r#"
+        fn test() {
+            let s: &str = "hello";
+            match s {
+                "hello" => {}
+                _ => {}
+            }
+        }
+        "#,
+        expect![[r#"
+            10..98 '{     ...   } }': ()
+            20..21 's': &str
+            30..37 '"hello"': &str
+            43..96 'match ...     }': ()
+            49..50 's': &str
+            61..68 '"hello"': &str
+            61..68 '"hello"': &str
+            72..74 '{}': ()
+            83..84 '_': &str
+            88..90 '{}': ()
+        "#]],
+    );
+}
+
+#[test]
+fn infer_pattern_match_or() {
+    check_infer_with_mismatches(
+        r#"
+        fn test() {
+            let s: &str = "hello";
+            match s {
+                "hello" | "world" => {}
+                _ => {}
+            }
+        }
+        "#,
+        expect![[r#"
+            10..108 '{     ...   } }': ()
+            20..21 's': &str
+            30..37 '"hello"': &str
+            43..106 'match ...     }': ()
+            49..50 's': &str
+            61..68 '"hello"': &str
+            61..68 '"hello"': &str
+            61..78 '"hello...world"': &str
+            71..78 '"world"': &str
+            71..78 '"world"': &str
+            82..84 '{}': ()
+            93..94 '_': &str
+            98..100 '{}': ()
+        "#]],
+    );
+}
+
+#[test]
+fn infer_pattern_match_arr() {
+    check_infer(
+        r#"
+        fn test() {
+            let arr: [f64; 2] = [0.0, 1.0];
+            match arr {
+                [1.0, a] => {
+                    a;
+                },
+                [b, c] => {
+                    b;
+                    c;
+                }
+            }
+        }
+        "#,
+        expect![[r#"
+            10..179 '{     ...   } }': ()
+            20..23 'arr': [f64; _]
+            36..46 '[0.0, 1.0]': [f64; _]
+            37..40 '0.0': f64
+            42..45 '1.0': f64
+            52..177 'match ...     }': ()
+            58..61 'arr': [f64; _]
+            72..80 '[1.0, a]': [f64; _]
+            73..76 '1.0': f64
+            73..76 '1.0': f64
+            78..79 'a': f64
+            84..110 '{     ...     }': ()
+            98..99 'a': f64
+            120..126 '[b, c]': [f64; _]
+            121..122 'b': f64
+            124..125 'c': f64
+            130..171 '{     ...     }': ()
+            144..145 'b': f64
+            159..160 'c': f64
+        "#]],
+    );
+}
+
+#[test]
+fn infer_adt_pattern() {
+    check_infer(
+        r#"
+        enum E {
+            A { x: usize },
+            B
+        }
+
+        struct S(u32, E);
+
+        fn test() {
+            let e = E::A { x: 3 };
+
+            let S(y, z) = foo;
+            let E::A { x: new_var } = e;
+
+            match e {
+                E::A { x } => x,
+                E::B if foo => 1,
+                E::B => 10,
+            };
+
+            let ref d @ E::A { .. } = e;
+            d;
+        }
+        "#,
+        expect![[r#"
+            67..288 '{     ...  d; }': ()
+            77..78 'e': E
+            81..94 'E::A { x: 3 }': E
+            91..92 '3': usize
+            105..112 'S(y, z)': S
+            107..108 'y': u32
+            110..111 'z': E
+            115..118 'foo': S
+            128..147 'E::A {..._var }': E
+            138..145 'new_var': usize
+            150..151 'e': E
+            158..244 'match ...     }': usize
+            164..165 'e': E
+            176..186 'E::A { x }': E
+            183..184 'x': usize
+            190..191 'x': usize
+            201..205 'E::B': E
+            209..212 'foo': bool
+            216..217 '1': usize
+            227..231 'E::B': E
+            235..237 '10': usize
+            255..274 'ref d ...{ .. }': &E
+            263..274 'E::A { .. }': E
+            277..278 'e': E
+            284..285 'd': &E
+        "#]],
+    );
+}
+
+#[test]
+fn enum_variant_through_self_in_pattern() {
+    check_infer(
+        r#"
+        enum E {
+            A { x: usize },
+            B(usize),
+            C
+        }
+
+        impl E {
+            fn test() {
+                match (loop {}) {
+                    Self::A { x } => { x; },
+                    Self::B(x) => { x; },
+                    Self::C => {},
+                };
+            }
+        }
+        "#,
+        expect![[r#"
+            75..217 '{     ...     }': ()
+            85..210 'match ...     }': ()
+            92..99 'loop {}': !
+            97..99 '{}': ()
+            115..128 'Self::A { x }': E
+            125..126 'x': usize
+            132..138 '{ x; }': ()
+            134..135 'x': usize
+            152..162 'Self::B(x)': E
+            160..161 'x': usize
+            166..172 '{ x; }': ()
+            168..169 'x': usize
+            186..193 'Self::C': E
+            197..199 '{}': ()
+        "#]],
+    );
+}
+
+#[test]
+fn infer_generics_in_patterns() {
+    check_infer(
+        r#"
+        struct A<T> {
+            x: T,
+        }
+
+        enum Option<T> {
+            Some(T),
+            None,
+        }
+
+        fn test(a1: A<u32>, o: Option<u64>) {
+            let A { x: x2 } = a1;
+            let A::<i64> { x: x3 } = A { x: 1 };
+            match o {
+                Option::Some(t) => t,
+                _ => 1,
+            };
+        }
+        "#,
+        expect![[r#"
+            78..80 'a1': A<u32>
+            90..91 'o': Option<u64>
+            106..243 '{     ...  }; }': ()
+            116..127 'A { x: x2 }': A<u32>
+            123..125 'x2': u32
+            130..132 'a1': A<u32>
+            142..160 'A::<i6...: x3 }': A<i64>
+            156..158 'x3': i64
+            163..173 'A { x: 1 }': A<i64>
+            170..171 '1': i64
+            179..240 'match ...     }': u64
+            185..186 'o': Option<u64>
+            197..212 'Option::Some(t)': Option<u64>
+            210..211 't': u64
+            216..217 't': u64
+            227..228 '_': Option<u64>
+            232..233 '1': u64
+        "#]],
+    );
+}
+
+#[test]
+fn infer_const_pattern() {
+    check_infer_with_mismatches(
+        r#"
+        enum Option<T> { None }
+        use Option::None;
+        struct Foo;
+        const Bar: usize = 1;
+
+        fn test() {
+            let a: Option<u32> = None;
+            let b: Option<i64> = match a {
+                None => None,
+            };
+            let _: () = match () { Foo => Foo }; // Expected mismatch
+            let _: () = match () { Bar => Bar }; // Expected mismatch
+        }
+        "#,
+        expect![[r#"
+            73..74 '1': usize
+            87..309 '{     ...atch }': ()
+            97..98 'a': Option<u32>
+            114..118 'None': Option<u32>
+            128..129 'b': Option<i64>
+            145..182 'match ...     }': Option<i64>
+            151..152 'a': Option<u32>
+            163..167 'None': Option<u32>
+            171..175 'None': Option<i64>
+            192..193 '_': ()
+            200..223 'match ... Foo }': Foo
+            206..208 '()': ()
+            211..214 'Foo': Foo
+            218..221 'Foo': Foo
+            254..255 '_': ()
+            262..285 'match ... Bar }': usize
+            268..270 '()': ()
+            273..276 'Bar': usize
+            280..283 'Bar': usize
+            200..223: expected (), got Foo
+            262..285: expected (), got usize
+        "#]],
+    );
+}
+
+#[test]
+fn infer_guard() {
+    check_infer(
+        r#"
+struct S;
+impl S { fn foo(&self) -> bool { false } }
+
+fn main() {
+    match S {
+        s if s.foo() => (),
+    }
+}
+        "#,
+        expect![[r#"
+            27..31 'self': &S
+            41..50 '{ false }': bool
+            43..48 'false': bool
+            64..115 '{     ...   } }': ()
+            70..113 'match ...     }': ()
+            76..77 'S': S
+            88..89 's': S
+            93..94 's': S
+            93..100 's.foo()': bool
+            104..106 '()': ()
+    "#]],
+    )
+}
+
+#[test]
+fn match_ergonomics_in_closure_params() {
+    check_infer(
+        r#"
+        #[lang = "fn_once"]
+        trait FnOnce<Args> {
+            type Output;
+        }
+
+        fn foo<T, U, F: FnOnce(T) -> U>(t: T, f: F) -> U { loop {} }
+
+        fn test() {
+            foo(&(1, "a"), |&(x, y)| x); // normal, no match ergonomics
+            foo(&(1, "a"), |(x, y)| x);
+        }
+        "#,
+        expect![[r#"
+            93..94 't': T
+            99..100 'f': F
+            110..121 '{ loop {} }': U
+            112..119 'loop {}': !
+            117..119 '{}': ()
+            133..232 '{     ... x); }': ()
+            139..142 'foo': fn foo<&(i32, &str), i32, |&(i32, &str)| -> i32>(&(i32, &str), |&(i32, &str)| -> i32) -> i32
+            139..166 'foo(&(...y)| x)': i32
+            143..152 '&(1, "a")': &(i32, &str)
+            144..152 '(1, "a")': (i32, &str)
+            145..146 '1': i32
+            148..151 '"a"': &str
+            154..165 '|&(x, y)| x': |&(i32, &str)| -> i32
+            155..162 '&(x, y)': &(i32, &str)
+            156..162 '(x, y)': (i32, &str)
+            157..158 'x': i32
+            160..161 'y': &str
+            164..165 'x': i32
+            203..206 'foo': fn foo<&(i32, &str), &i32, |&(i32, &str)| -> &i32>(&(i32, &str), |&(i32, &str)| -> &i32) -> &i32
+            203..229 'foo(&(...y)| x)': &i32
+            207..216 '&(1, "a")': &(i32, &str)
+            208..216 '(1, "a")': (i32, &str)
+            209..210 '1': i32
+            212..215 '"a"': &str
+            218..228 '|(x, y)| x': |&(i32, &str)| -> &i32
+            219..225 '(x, y)': (i32, &str)
+            220..221 'x': &i32
+            223..224 'y': &&str
+            227..228 'x': &i32
+        "#]],
+    );
+}
+
+#[test]
+fn slice_tail_pattern() {
+    check_infer(
+        r#"
+        fn foo(params: &[i32]) {
+            match params {
+                [head, tail @ ..] => {
+                }
+            }
+        }
+        "#,
+        expect![[r#"
+            7..13 'params': &[i32]
+            23..92 '{     ...   } }': ()
+            29..90 'match ...     }': ()
+            35..41 'params': &[i32]
+            52..69 '[head,... @ ..]': [i32]
+            53..57 'head': &i32
+            59..68 'tail @ ..': &[i32]
+            66..68 '..': [i32]
+            73..84 '{         }': ()
+        "#]],
+    );
+}