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 <[email protected]>

4 files changed, 78 insertions, 6 deletions

diff --git a/crates/ra_syntax/tests/data/parser/inline/err/0010_bad_tuple_index_expr.rs b/crates/ra_syntax/tests/data/parser/inline/err/0010_bad_tuple_index_expr.rs
new file mode 100644
index 000000000..30cc49138
--- /dev/null
+++ b/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;
+}
diff --git a/crates/ra_syntax/tests/data/parser/inline/err/0010_bad_tuple_index_expr.txt b/crates/ra_syntax/tests/data/parser/inline/err/0010_bad_tuple_index_expr.txt
new file mode 100644
index 000000000..c111f60ea
--- /dev/null
+++ b/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"
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.rs b/crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.rs
index 3e69538e5..b8da2ddc3 100644
--- a/crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.rs
+++ b/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();
 }
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.txt b/crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.txt
index a86702843..78054ec5a 100644
--- a/crates/ra_syntax/tests/data/parser/inline/ok/0011_field_expr.txt
+++ b/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"