Merge #520

520: Imprement tuple inference r=flodiebold a=h-michael

related #394

I'm sorry I'm late.

I try implementing array inference next.

Co-authored-by: Hirokazu Hata <h.hata.ai.t@gmail.com>

crates/ra_hir/src/expr.rs

@@ -183,6 +183,9 @@ pub enum Expr {
         arg_types: Vec<Option<TypeRef>>,
         body: ExprId,
     },
+    Tuple {
+        exprs: Vec<ExprId>,
+    },
 }
 
 pub use ra_syntax::ast::PrefixOp as UnaryOp;
@@ -297,6 +300,11 @@ impl Expr {
             | Expr::UnaryOp { expr, .. } => {
                 f(*expr);
             }
+            Expr::Tuple { exprs } => {
+                for expr in exprs {
+                    f(*expr);
+                }
+            }
         }
     }
 }
@@ -621,11 +629,14 @@ impl ExprCollector {
                 let op = e.op();
                 self.alloc_expr(Expr::BinaryOp { lhs, rhs, op }, syntax_ptr)
             }
+            ast::ExprKind::TupleExpr(e) => {
+                let exprs = e.exprs().map(|expr| self.collect_expr(expr)).collect();
+                self.alloc_expr(Expr::Tuple { exprs }, syntax_ptr)
+            }
 
             // TODO implement HIR for these:
             ast::ExprKind::Label(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::ExprKind::IndexExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
-            ast::ExprKind::TupleExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::ExprKind::ArrayExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::ExprKind::RangeExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::ExprKind::Literal(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),

crates/ra_hir/src/ty.rs

@@ -1040,6 +1040,14 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 }
                 _ => Ty::Unknown,
             },
+            Expr::Tuple { exprs } => {
+                let mut ty_vec = Vec::with_capacity(exprs.len());
+                for arg in exprs.iter() {
+                    ty_vec.push(self.infer_expr(*arg, &Expectation::none())?);
+                }
+
+                Ty::Tuple(Arc::from(ty_vec))
+            }
         };
         // use a new type variable if we got Ty::Unknown here
         let ty = self.insert_type_vars_shallow(ty);

crates/ra_hir/src/ty/tests.rs

@@ -268,6 +268,25 @@ fn test(a: A) {
     );
 }
 
+#[test]
+fn infer_tuple() {
+    check_inference(
+        r#"
+fn test(x: &str, y: isize) {
+    let a: (u32, &str) = (1, "a");
+    let b = (a, x);
+    let c = (y, x);
+    let d = (c, x);
+
+    // we have not infered these case yet.
+    let e = (1, "e");
+    let f = (e, "d");
+}
+"#,
+        "tuple.txt",
+    );
+}
+
 fn infer(content: &str) -> String {
     let (db, _, file_id) = MockDatabase::with_single_file(content);
     let source_file = db.source_file(file_id);

crates/ra_hir/src/ty/tests/data/tuple.txt

@@ -0,0 +1,27 @@
+[9; 10) 'x': &str
+[18; 19) 'y': isize
+[28; 214) '{     ...d"); }': ()
+[38; 39) 'a': (u32, &str)
+[55; 63) '(1, "a")': (u32, &str)
+[56; 57) '1': u32
+[59; 62) '"a"': &str
+[73; 74) 'b': ((u32, &str), &str)
+[77; 83) '(a, x)': ((u32, &str), &str)
+[78; 79) 'a': (u32, &str)
+[81; 82) 'x': &str
+[93; 94) 'c': (isize, &str)
+[97; 103) '(y, x)': (isize, &str)
+[98; 99) 'y': isize
+[101; 102) 'x': &str
+[113; 114) 'd': ((isize, &str), &str)
+[117; 123) '(c, x)': ((isize, &str), &str)
+[118; 119) 'c': (isize, &str)
+[121; 122) 'x': &str
+[177; 178) 'e': ([unknown], [unknown])
+[181; 189) '(1, "e")': ([unknown], [unknown])
+[182; 183) '1': [unknown]
+[185; 188) '"e"': [unknown]
+[199; 200) 'f': (([unknown], [unknown]), [unknown])
+[203; 211) '(e, "d")': (([unknown], [unknown]), [unknown])
+[204; 205) 'e': ([unknown], [unknown])
+[207; 210) '"d"': [unknown]

crates/ra_syntax/src/ast/generated.rs

@@ -2969,7 +2969,11 @@ impl AstNode for TupleExpr {
 }
 
 
-impl TupleExpr {}
+impl TupleExpr {
+    pub fn exprs(&self) -> impl Iterator<Item = &Expr> {
+        super::children(self)
+    }
+}
 
 // TuplePat
 #[derive(Debug, PartialEq, Eq, Hash)]

crates/ra_syntax/src/grammar.ron

@@ -357,7 +357,9 @@ Grammar(
             enum: ["FnDef", "TypeDef", "ConstDef"]
         ),
 
-        "TupleExpr": (),
+        "TupleExpr": (
+            collections: [["exprs", "Expr"]]
+        ),
         "ArrayExpr": (),
         "ParenExpr": (options: ["Expr"]),
         "PathExpr": (options: ["Path"]),