Merge #1117

1117: [WIP] Tuple struct index inference r=matklad a=robojumper

The first commit adds a helper struct `ast::FieldKind` to facilitate inference.

The second commit adds a slightly modified test from #1109 while mentioning that there is a problem with how we're handling tuple indexing / floats.

cc #1109 

Co-authored-by: robojumper <robojumper@gmail.com>

Author: bors[bot]

crates/ra_hir/src/expr.rs

@@ -671,7 +671,10 @@ impl ExprCollector {
             }
             ast::ExprKind::FieldExpr(e) => {
                 let expr = self.collect_expr_opt(e.expr());
-                let name = e.name_ref().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
+                let name = match e.field_access() {
+                    Some(kind) => kind.as_name(),
+                    _ => Name::missing(),
+                };
                 self.alloc_expr(Expr::Field { expr, name }, syntax_ptr)
             }
             ast::ExprKind::TryExpr(e) => {

crates/ra_hir/src/name.rs

@@ -90,6 +90,15 @@ impl AsName for ast::Name {
     }
 }
 
+impl<'a> AsName for ast::FieldKind<'a> {
+    fn as_name(&self) -> Name {
+        match self {
+            ast::FieldKind::Name(nr) => nr.as_name(),
+            ast::FieldKind::Index(idx) => Name::new(idx.text().clone()),
+        }
+    }
+}
+
 impl AsName for ra_db::Dependency {
     fn as_name(&self) -> Name {
         Name::new(self.name.clone())

crates/ra_hir/src/ty/tests.rs

@@ -2242,6 +2242,65 @@ static B: u64 = { let x = 1; x };
     );
 }
 
+#[test]
+fn tuple_struct_fields() {
+    assert_snapshot_matches!(
+        infer(r#"
+struct S(i32, u64);
+fn test() -> u64 {
+    let a = S(4, 6);
+    let b = a.0;
+    a.1
+}
+"#),
+        @r###"
+[38; 87) '{     ... a.1 }': u64
+[48; 49) 'a': S
+[52; 53) 'S': S(i32, u64) -> S
+[52; 59) 'S(4, 6)': S
+[54; 55) '4': i32
+[57; 58) '6': u64
+[69; 70) 'b': i32
+[73; 74) 'a': S
+[73; 76) 'a.0': i32
+[82; 83) 'a': S
+[82; 85) 'a.1': u64"###
+    );
+}
+
+#[test]
+fn tuple_struct_with_fn() {
+    assert_snapshot_matches!(
+        infer(r#"
+struct S(fn(u32) -> u64);
+fn test() -> u64 {
+    let a = S(|i| 2*i);
+    let b = a.0(4);
+    a.0(2)
+}
+"#),
+        @r###"
+[44; 102) '{     ...0(2) }': u64
+[54; 55) 'a': S
+[58; 59) 'S': S(fn(u32) -> u64) -> S
+[58; 68) 'S(|i| 2*i)': S
+[60; 67) '|i| 2*i': fn(u32) -> u64
+[61; 62) 'i': i32
+[64; 65) '2': i32
+[64; 67) '2*i': i32
+[66; 67) 'i': i32
+[78; 79) 'b': u64
+[82; 83) 'a': S
+[82; 85) 'a.0': fn(u32) -> u64
+[82; 88) 'a.0(4)': u64
+[86; 87) '4': u32
+[94; 95) 'a': S
+[94; 97) 'a.0': fn(u32) -> u64
+[94; 100) 'a.0(2)': u64
+[98; 99) '2': u32"###
+    );
+}
+
 fn type_at_pos(db: &MockDatabase, pos: FilePosition) -> String {
     let func = source_binder::function_from_position(db, pos).unwrap();
     let body_source_map = func.body_source_map(db);

crates/ra_ide_api/src/completion/complete_dot.rs

@@ -184,4 +184,26 @@ mod tests {
             ",
         );
     }
+
+    #[test]
+    fn test_tuple_field_inference() {
+        check_ref_completion(
+            "tuple_field_inference",
+            r"
+            pub struct S;
+            impl S {
+                pub fn blah(&self) {}
+            }
+
+            struct T(S);
+
+            impl T {
+                fn foo(&self) {
+                    // FIXME: This doesn't work without the trailing `a` as `0.` is a float
+                    self.0.a<|>
+                }
+            }
+            ",
+        );
+    }
 }

crates/ra_ide_api/src/completion/snapshots/completion_item__tuple_field_inference.snap

@@ -0,0 +1,16 @@
+---
+created: "2019-04-05T23:00:18.283812700Z"
+creator: insta@0.7.4
+source: crates/ra_ide_api/src/completion/completion_item.rs
+expression: kind_completions
+---
+[
+    CompletionItem {
+        label: "blah",
+        source_range: [299; 300),
+        delete: [299; 300),
+        insert: "blah()$0",
+        kind: Method,
+        detail: "pub fn blah(&self)"
+    }
+]

crates/ra_parser/src/grammar/expressions.rs

@@ -379,6 +379,14 @@ fn method_call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
 // fn foo() {
 //     x.foo;
 //     x.0.bar;
+//     x.0();
+// }
+
+// test_err bad_tuple_index_expr
+// fn foo() {
+//     x.0.;
+//     x.1i32;
+//     x.0x01;
 // }
 fn field_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
     assert!(p.at(DOT));
@@ -387,7 +395,10 @@ fn field_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
     if p.at(IDENT) {
         name_ref(p)
     } else if p.at(INT_NUMBER) {
-        p.bump()
+        p.bump();
+    } else if p.at(FLOAT_NUMBER) {
+        // FIXME: How to recover and instead parse INT + DOT?
+        p.bump();
     } else {
         p.error("expected field name or number")
     }

crates/ra_syntax/src/ast.rs

@@ -17,7 +17,7 @@ pub use self::{
     generated::*,
     traits::*,
     tokens::*,
-    extensions::{PathSegmentKind, StructKind, SelfParamKind},
+    extensions::{PathSegmentKind, StructKind, FieldKind, SelfParamKind},
     expr_extensions::{ElseBranch, PrefixOp, BinOp, LiteralKind},
 };
 

crates/ra_syntax/src/ast/extensions.rs

@@ -3,11 +3,8 @@
 
 use itertools::Itertools;
 
-use crate::{
-    SmolStr, SyntaxToken,
-    ast::{self, AstNode, children, child_opt},
-    SyntaxKind::*,
-};
+use crate::{SmolStr, SyntaxToken, ast::{self, AstNode, children, child_opt}, SyntaxKind::*, SyntaxElement};
+use ra_parser::SyntaxKind;
 
 impl ast::Name {
     pub fn text(&self) -> &SmolStr {
@@ -217,6 +214,33 @@ impl ast::ExprStmt {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum FieldKind<'a> {
+    Name(&'a ast::NameRef),
+    Index(SyntaxToken<'a>),
+}
+
+impl ast::FieldExpr {
+    pub fn index_token(&self) -> Option<SyntaxToken> {
+        self.syntax
+            .children_with_tokens()
+            // FIXME: Accepting floats here to reject them in validation later
+            .find(|c| c.kind() == SyntaxKind::INT_NUMBER || c.kind() == SyntaxKind::FLOAT_NUMBER)
+            .as_ref()
+            .and_then(SyntaxElement::as_token)
+    }
+
+    pub fn field_access(&self) -> Option<FieldKind> {
+        if let Some(nr) = self.name_ref() {
+            Some(FieldKind::Name(nr))
+        } else if let Some(tok) = self.index_token() {
+            Some(FieldKind::Index(tok))
+        } else {
+            None
+        }
+    }
+}
+
 impl ast::RefPat {
     pub fn is_mut(&self) -> bool {
         self.syntax().children_with_tokens().any(|n| n.kind() == MUT_KW)

crates/ra_syntax/src/syntax_error.rs

@@ -95,6 +95,7 @@ pub enum SyntaxErrorKind {
     InvalidSuffix,
     InvalidBlockAttr,
     InvalidMatchInnerAttr,
+    InvalidTupleIndexFormat,
 }
 
 impl fmt::Display for SyntaxErrorKind {
@@ -139,6 +140,9 @@ impl fmt::Display for SyntaxErrorKind {
             InvalidMatchInnerAttr => {
                 write!(f, "Inner attributes are only allowed directly after the opening brace of the match expression")
             }
+            InvalidTupleIndexFormat => {
+                write!(f, "Tuple (struct) field access is only allowed through decimal integers with no underscores or suffix")
+            }
             ParseError(msg) => write!(f, "{}", msg.0),
         }
     }

crates/ra_syntax/src/validation.rs

@@ -3,6 +3,7 @@ mod byte_string;
 mod char;
 mod string;
 mod block;
+mod field_expr;
 
 use crate::{
     SourceFile, SyntaxError, AstNode, SyntaxNode,
@@ -17,6 +18,7 @@ pub(crate) fn validate(file: &SourceFile) -> Vec<SyntaxError> {
         let _ = visitor_ctx(&mut errors)
             .visit::<ast::Literal, _>(validate_literal)
             .visit::<ast::Block, _>(block::validate_block_node)
+            .visit::<ast::FieldExpr, _>(field_expr::validate_field_expr_node)
             .accept(node);
     }
     errors

crates/ra_syntax/src/validation/field_expr.rs

@@ -0,0 +1,12 @@
+use crate::{ast::{self, FieldKind},
+            SyntaxError,
+            SyntaxErrorKind::*,
+};
+
+pub(crate) fn validate_field_expr_node(node: &ast::FieldExpr, errors: &mut Vec<SyntaxError>) {
+    if let Some(FieldKind::Index(idx)) = node.field_access() {
+        if idx.text().chars().any(|c| c < '0' || c > '9') {
+            errors.push(SyntaxError::new(InvalidTupleIndexFormat, idx.range()));
+        }
+    }
+}

crates/ra_syntax/tests/data/parser/inline/err/0010_bad_tuple_index_expr.rs

@@ -0,0 +1,5 @@
+fn foo() {
+    x.0.;
+    x.1i32;
+    x.0x01;
+}

crates/ra_syntax/tests/data/parser/inline/err/0010_bad_tuple_index_expr.txt

@@ -0,0 +1,51 @@
+SOURCE_FILE@[0; 47)
+  FN_DEF@[0; 46)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 6)
+      IDENT@[3; 6) "foo"
+    PARAM_LIST@[6; 8)
+      L_PAREN@[6; 7) "("
+      R_PAREN@[7; 8) ")"
+    WHITESPACE@[8; 9) " "
+    BLOCK@[9; 46)
+      L_CURLY@[9; 10) "{"
+      WHITESPACE@[10; 15) "\n    "
+      EXPR_STMT@[15; 20)
+        FIELD_EXPR@[15; 19)
+          PATH_EXPR@[15; 16)
+            PATH@[15; 16)
+              PATH_SEGMENT@[15; 16)
+                NAME_REF@[15; 16)
+                  IDENT@[15; 16) "x"
+          DOT@[16; 17) "."
+          err: `Tuple (struct) field access is only allowed through decimal integers with no underscores or suffix`
+          FLOAT_NUMBER@[17; 19) "0."
+        SEMI@[19; 20) ";"
+      WHITESPACE@[20; 25) "\n    "
+      EXPR_STMT@[25; 32)
+        FIELD_EXPR@[25; 31)
+          PATH_EXPR@[25; 26)
+            PATH@[25; 26)
+              PATH_SEGMENT@[25; 26)
+                NAME_REF@[25; 26)
+                  IDENT@[25; 26) "x"
+          DOT@[26; 27) "."
+          err: `Tuple (struct) field access is only allowed through decimal integers with no underscores or suffix`
+          INT_NUMBER@[27; 31) "1i32"
+        SEMI@[31; 32) ";"
+      WHITESPACE@[32; 37) "\n    "
+      EXPR_STMT@[37; 44)
+        FIELD_EXPR@[37; 43)
+          PATH_EXPR@[37; 38)
+            PATH@[37; 38)
+              PATH_SEGMENT@[37; 38)
+                NAME_REF@[37; 38)
+                  IDENT@[37; 38) "x"
+          DOT@[38; 39) "."
+          err: `Tuple (struct) field access is only allowed through decimal integers with no underscores or suffix`
+          INT_NUMBER@[39; 43) "0x01"
+        SEMI@[43; 44) ";"
+      WHITESPACE@[44; 45) "\n"
+      R_CURLY@[45; 46) "}"
+  WHITESPACE@[46; 47) "\n"

crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.rs

@@ -1,4 +1,5 @@
 fn foo() {
     x.foo;
     x.0.bar;
+    x.0();
 }

crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.txt

@@ -1,5 +1,5 @@
-SOURCE_FILE@[0; 37)
-  FN_DEF@[0; 36)
+SOURCE_FILE@[0; 48)
+  FN_DEF@[0; 47)
     FN_KW@[0; 2) "fn"
     WHITESPACE@[2; 3) " "
     NAME@[3; 6)
@@ -8,7 +8,7 @@ SOURCE_FILE@[0; 37)
       L_PAREN@[6; 7) "("
       R_PAREN@[7; 8) ")"
     WHITESPACE@[8; 9) " "
-    BLOCK@[9; 36)
+    BLOCK@[9; 47)
       L_CURLY@[9; 10) "{"
       WHITESPACE@[10; 15) "\n    "
       EXPR_STMT@[15; 21)
@@ -37,6 +37,21 @@ SOURCE_FILE@[0; 37)
           NAME_REF@[30; 33)
             IDENT@[30; 33) "bar"
         SEMI@[33; 34) ";"
-      WHITESPACE@[34; 35) "\n"
-      R_CURLY@[35; 36) "}"
-  WHITESPACE@[36; 37) "\n"
+      WHITESPACE@[34; 39) "\n    "
+      EXPR_STMT@[39; 45)
+        CALL_EXPR@[39; 44)
+          FIELD_EXPR@[39; 42)
+            PATH_EXPR@[39; 40)
+              PATH@[39; 40)
+                PATH_SEGMENT@[39; 40)
+                  NAME_REF@[39; 40)
+                    IDENT@[39; 40) "x"
+            DOT@[40; 41) "."
+            INT_NUMBER@[41; 42) "0"
+          ARG_LIST@[42; 44)
+            L_PAREN@[42; 43) "("
+            R_PAREN@[43; 44) ")"
+        SEMI@[44; 45) ";"
+      WHITESPACE@[45; 46) "\n"
+      R_CURLY@[46; 47) "}"
+  WHITESPACE@[47; 48) "\n"