Merge #7020

7020: Implement const pat and expr inference r=flodiebold a=Veykril



Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

crates/hir_ty/src/infer/expr.rs

@@ -155,7 +155,7 @@ impl<'a> InferenceContext<'a> {
                 }
                 None => self.infer_block(statements, *tail, expected),
             },
-            Expr::Unsafe { body } => self.infer_expr(*body, expected),
+            Expr::Unsafe { body } | Expr::Const { body } => self.infer_expr(*body, expected),
             Expr::TryBlock { body } => {
                 let _inner = self.infer_expr(*body, expected);
                 // FIXME should be std::result::Result<{inner}, _>

crates/hir_ty/src/infer/pat.rs

@@ -243,6 +243,9 @@ impl<'a> InferenceContext<'a> {
                 }
                 None => Ty::Unknown,
             },
+            Pat::ConstBlock(expr) => {
+                self.infer_expr(*expr, &Expectation::has_type(expected.clone()))
+            }
             Pat::Missing => Ty::Unknown,
         };
         // use a new type variable if we got Ty::Unknown here
@@ -264,8 +267,9 @@ fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool {
         | Pat::Range { .. }
         | Pat::Slice { .. } => true,
         Pat::Or(pats) => pats.iter().all(|p| is_non_ref_pat(body, *p)),
-        // FIXME: Path/Lit might actually evaluate to ref, but inference is unimplemented.
+        // FIXME: ConstBlock/Path/Lit might actually evaluate to ref, but inference is unimplemented.
         Pat::Path(..) => true,
+        Pat::ConstBlock(..) => true,
         Pat::Lit(expr) => match body[*expr] {
             Expr::Literal(Literal::String(..)) => false,
             _ => true,

crates/hir_ty/src/tests/patterns.rs

@@ -774,3 +774,33 @@ fn foo(tuple: Tuple) {
         "#]],
     );
 }
+
+#[test]
+fn const_block_pattern() {
+    check_infer(
+        r#"
+struct Foo(usize);
+fn foo(foo: Foo) {
+    match foo {
+        const { Foo(15 + 32) } => {},
+        _ => {}
+    }
+}"#,
+        expect![[r#"
+            26..29 'foo': Foo
+            36..115 '{     ...   } }': ()
+            42..113 'match ...     }': ()
+            48..51 'foo': Foo
+            62..84 'const ... 32) }': Foo
+            68..84 '{ Foo(... 32) }': Foo
+            70..73 'Foo': Foo(usize) -> Foo
+            70..82 'Foo(15 + 32)': Foo
+            74..76 '15': usize
+            74..81 '15 + 32': usize
+            79..81 '32': usize
+            88..90 '{}': ()
+            100..101 '_': Foo
+            105..107 '{}': ()
+        "#]],
+    );
+}

crates/hir_ty/src/tests/simple.rs

@@ -1894,6 +1894,7 @@ fn effects_smoke_test() {
             let x = unsafe { 92 };
             let y = async { async { () }.await };
             let z = try { () };
+            let w = const { 92 };
             let t = 'a: { 92 };
         }
 
@@ -1905,7 +1906,7 @@ fn effects_smoke_test() {
         }
         "#,
         expect![[r#"
-            16..136 '{     ...2 }; }': ()
+            16..162 '{     ...2 }; }': ()
             26..27 'x': i32
             30..43 'unsafe { 92 }': i32
             37..43 '{ 92 }': i32
@@ -1921,9 +1922,13 @@ fn effects_smoke_test() {
             99..109 'try { () }': {unknown}
             103..109 '{ () }': ()
             105..107 '()': ()
-            119..120 't': i32
-            127..133 '{ 92 }': i32
-            129..131 '92': i32
+            119..120 'w': i32
+            123..135 'const { 92 }': i32
+            129..135 '{ 92 }': i32
+            131..133 '92': i32
+            145..146 't': i32
+            153..159 '{ 92 }': i32
+            155..157 '92': i32
         "#]],
     )
 }