Improve the spans of some deriving traits

src/etc/generate-deriving-span-tests.py

@@ -0,0 +1,131 @@
+#!/usr/bin/env python
+# xfail-license
+# Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution and at
+# http://rust-lang.org/COPYRIGHT.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+"""
+This script creates a pile of compile-fail tests check that all the
+derivings have spans that point to the fields, rather than the
+#[deriving(...)] line.
+
+sample usage: src/etc/generate-deriving-span-tests.py
+"""
+
+import sys, os, datetime, stat
+
+TEST_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '../test/compile-fail'))
+
+YEAR = datetime.datetime.now().year
+
+TEMPLATE = """// Copyright {year} The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// This file was auto-generated using 'src/etc/generate-keyword-span-tests.py'
+
+#[feature(struct_variant)];
+extern mod extra;
+
+{error_deriving}
+struct Error;
+{code}
+fn main() {{}}
+"""
+
+ENUM_STRING = """
+#[deriving({traits})]
+enum Enum {{
+   A(
+     Error {errors}
+     )
+}}
+"""
+ENUM_STRUCT_VARIANT_STRING = """
+#[deriving({traits})]
+enum Enum {{
+   A {{
+     x: Error {errors}
+   }}
+}}
+"""
+STRUCT_STRING = """
+#[deriving({traits})]
+struct Struct {{
+    x: Error {errors}
+}}
+"""
+STRUCT_TUPLE_STRING = """
+#[deriving({traits})]
+struct Struct(
+    Error {errors}
+);
+"""
+
+ENUM_TUPLE, ENUM_STRUCT, STRUCT_FIELDS, STRUCT_TUPLE = range(4)
+
+def create_test_case(type, trait, super_traits, number_of_errors):
+    string = [ENUM_STRING, ENUM_STRUCT_VARIANT_STRING, STRUCT_STRING, STRUCT_TUPLE_STRING][type]
+    all_traits = ','.join([trait] + super_traits)
+    super_traits = ','.join(super_traits)
+    error_deriving = '#[deriving(%s)]' % super_traits if super_traits else ''
+
+    errors = '\n'.join('//~%s ERROR' % ('^' * n) for n in range(error_count))
+    code = string.format(traits = all_traits, errors = errors)
+    return TEMPLATE.format(year = YEAR, error_deriving=error_deriving, code = code)
+
+def write_file(name, string):
+    test_file = os.path.join(TEST_DIR, 'deriving-span-%s.rs' % name)
+
+    # set write permission if file exists, so it can be changed
+    if os.path.exists(test_file):
+        os.chmod(test_file, stat.S_IWUSR)
+
+    with open(test_file, 'wt') as f:
+        f.write(string)
+
+    # mark file read-only
+    os.chmod(test_file, stat.S_IRUSR|stat.S_IRGRP|stat.S_IROTH)
+
+
+
+ENUM = 1
+STRUCT = 2
+ALL = STRUCT | ENUM
+
+traits = {
+    'Zero': (STRUCT, [], 1),
+    'Default': (STRUCT, [], 1),
+    'FromPrimitive': (0, [], 0), # only works for C-like enums
+
+    'Decodable': (0, [], 0), # FIXME: quoting gives horrible spans
+    'Encodable': (0, [], 0), # FIXME: quoting gives horrible spans
+}
+
+for (trait, supers, errs) in [('Rand', [], 1),
+                              ('Clone', [], 1), ('DeepClone', ['Clone'], 1),
+                              ('Eq', [], 2), ('Ord', [], 8),
+                              ('TotalEq', [], 2), ('TotalOrd', ['TotalEq'], 2)]:
+    traits[trait] = (ALL, supers, errs)
+
+for (trait, (types, super_traits, error_count)) in traits.items():
+    mk = lambda ty: create_test_case(ty, trait, super_traits, error_count)
+    if types & ENUM:
+        write_file(trait + '-enum', mk(ENUM_TUPLE))
+        write_file(trait + '-enum-struct-variant', mk(ENUM_STRUCT))
+    if types & STRUCT:
+        write_file(trait + '-struct', mk(STRUCT_FIELDS))
+        write_file(trait + '-tuple-struct', mk(STRUCT_TUPLE))

src/libsyntax/ext/deriving/clone.rs

@@ -74,13 +74,13 @@ pub fn expand_deriving_deep_clone(cx: &ExtCtxt,
 
 fn cs_clone(
     name: &str,
-    cx: &ExtCtxt, span: Span,
+    cx: &ExtCtxt, trait_span: Span,
     substr: &Substructure) -> @Expr {
     let clone_ident = substr.method_ident;
     let ctor_ident;
     let all_fields;
-    let subcall = |field|
-        cx.expr_method_call(span, field, clone_ident, ~[]);
+    let subcall = |field: &FieldInfo|
+        cx.expr_method_call(field.span, field.self_, clone_ident, ~[]);
 
     match *substr.fields {
         Struct(ref af) => {
@@ -91,37 +91,37 @@ fn cs_clone(
             ctor_ident = variant.node.name;
             all_fields = af;
         },
-        EnumNonMatching(..) => cx.span_bug(span,
-                                          format!("Non-matching enum variants in `deriving({})`",
-                                               name)),
-        StaticEnum(..) | StaticStruct(..) => cx.span_bug(span,
-                                                       format!("Static method in `deriving({})`",
-                                                            name))
+        EnumNonMatching(..) => cx.span_bug(trait_span,
+                                           format!("Non-matching enum variants in `deriving({})`",
+                                                  name)),
+        StaticEnum(..) | StaticStruct(..) => cx.span_bug(trait_span,
+                                                         format!("Static method in `deriving({})`",
+                                                                 name))
     }
 
     match *all_fields {
         [FieldInfo { name: None, .. }, ..] => {
             // enum-like
-            let subcalls = all_fields.map(|field| subcall(field.self_));
-            cx.expr_call_ident(span, ctor_ident, subcalls)
+            let subcalls = all_fields.map(subcall);
+            cx.expr_call_ident(trait_span, ctor_ident, subcalls)
         },
         _ => {
             // struct-like
             let fields = all_fields.map(|field| {
                 let ident = match field.name {
                     Some(i) => i,
-                    None => cx.span_bug(span,
+                    None => cx.span_bug(trait_span,
                                         format!("unnamed field in normal struct in `deriving({})`",
-                                             name))
+                                                name))
                 };
-                cx.field_imm(span, ident, subcall(field.self_))
+                cx.field_imm(field.span, ident, subcall(field))
             });
 
             if fields.is_empty() {
                 // no fields, so construct like `None`
-                cx.expr_ident(span, ctor_ident)
+                cx.expr_ident(trait_span, ctor_ident)
             } else {
-                cx.expr_struct_ident(span, ctor_ident, fields)
+                cx.expr_struct_ident(trait_span, ctor_ident, fields)
             }
         }
     }

src/libsyntax/ext/deriving/decodable.rs

@@ -51,7 +51,7 @@ pub fn expand_deriving_decodable(cx: &ExtCtxt,
     trait_def.expand(mitem, in_items)
 }
 
-fn decodable_substructure(cx: &ExtCtxt, span: Span,
+fn decodable_substructure(cx: &ExtCtxt, trait_span: Span,
                           substr: &Substructure) -> @Expr {
     let decoder = substr.nonself_args[0];
     let recurse = ~[cx.ident_of("extra"),
@@ -60,9 +60,9 @@ fn decodable_substructure(cx: &ExtCtxt, span: Span,
                     cx.ident_of("decode")];
     // throw an underscore in front to suppress unused variable warnings
     let blkarg = cx.ident_of("_d");
-    let blkdecoder = cx.expr_ident(span, blkarg);
-    let calldecode = cx.expr_call_global(span, recurse, ~[blkdecoder]);
-    let lambdadecode = cx.lambda_expr_1(span, calldecode, blkarg);
+    let blkdecoder = cx.expr_ident(trait_span, blkarg);
+    let calldecode = cx.expr_call_global(trait_span, recurse, ~[blkdecoder]);
+    let lambdadecode = cx.lambda_expr_1(trait_span, calldecode, blkarg);
 
     return match *substr.fields {
         StaticStruct(_, ref summary) => {
@@ -73,7 +73,7 @@ fn decodable_substructure(cx: &ExtCtxt, span: Span,
             let read_struct_field = cx.ident_of("read_struct_field");
 
             let result = decode_static_fields(cx,
-                                              span,
+                                              trait_span,
                                               substr.type_ident,
                                               summary,
                                               |span, name, field| {
@@ -82,10 +82,10 @@ fn decodable_substructure(cx: &ExtCtxt, span: Span,
                                       cx.expr_uint(span, field),
                                       lambdadecode])
             });
-            cx.expr_method_call(span, decoder, cx.ident_of("read_struct"),
-                                ~[cx.expr_str(span, cx.str_of(substr.type_ident)),
-                                  cx.expr_uint(span, nfields),
-                                  cx.lambda_expr_1(span, result, blkarg)])
+            cx.expr_method_call(trait_span, decoder, cx.ident_of("read_struct"),
+                                ~[cx.expr_str(trait_span, cx.str_of(substr.type_ident)),
+                                  cx.expr_uint(trait_span, nfields),
+                                  cx.lambda_expr_1(trait_span, result, blkarg)])
         }
         StaticEnum(_, ref fields) => {
             let variant = cx.ident_of("i");
@@ -94,12 +94,11 @@ fn decodable_substructure(cx: &ExtCtxt, span: Span,
             let mut variants = ~[];
             let rvariant_arg = cx.ident_of("read_enum_variant_arg");
 
-            for (i, f) in fields.iter().enumerate() {
-                let (name, parts) = match *f { (i, ref p) => (i, p) };
-                variants.push(cx.expr_str(span, cx.str_of(name)));
+            for (i, &(name, v_span, ref parts)) in fields.iter().enumerate() {
+                variants.push(cx.expr_str(v_span, cx.str_of(name)));
 
                 let decoded = decode_static_fields(cx,
-                                                   span,
+                                                   v_span,
                                                    name,
                                                    parts,
                                                    |span, _, field| {
@@ -108,22 +107,22 @@ fn decodable_substructure(cx: &ExtCtxt, span: Span,
                                           lambdadecode])
                 });
 
-                arms.push(cx.arm(span,
-                                 ~[cx.pat_lit(span, cx.expr_uint(span, i))],
+                arms.push(cx.arm(v_span,
+                                 ~[cx.pat_lit(v_span, cx.expr_uint(v_span, i))],
                                  decoded));
             }
 
-            arms.push(cx.arm_unreachable(span));
+            arms.push(cx.arm_unreachable(trait_span));
 
-            let result = cx.expr_match(span, cx.expr_ident(span, variant), arms);
-            let lambda = cx.lambda_expr(span, ~[blkarg, variant], result);
-            let variant_vec = cx.expr_vec(span, variants);
-            let result = cx.expr_method_call(span, blkdecoder,
+            let result = cx.expr_match(trait_span, cx.expr_ident(trait_span, variant), arms);
+            let lambda = cx.lambda_expr(trait_span, ~[blkarg, variant], result);
+            let variant_vec = cx.expr_vec(trait_span, variants);
+            let result = cx.expr_method_call(trait_span, blkdecoder,
                                              cx.ident_of("read_enum_variant"),
                                              ~[variant_vec, lambda]);
-            cx.expr_method_call(span, decoder, cx.ident_of("read_enum"),
-                                ~[cx.expr_str(span, cx.str_of(substr.type_ident)),
-                                  cx.lambda_expr_1(span, result, blkarg)])
+            cx.expr_method_call(trait_span, decoder, cx.ident_of("read_enum"),
+                                ~[cx.expr_str(trait_span, cx.str_of(substr.type_ident)),
+                                  cx.lambda_expr_1(trait_span, result, blkarg)])
         }
         _ => cx.bug("expected StaticEnum or StaticStruct in deriving(Decodable)")
     };
@@ -133,29 +132,29 @@ fn decodable_substructure(cx: &ExtCtxt, span: Span,
 /// - `outer_pat_ident` is the name of this enum variant/struct
 /// - `getarg` should retrieve the `uint`-th field with name `@str`.
 fn decode_static_fields(cx: &ExtCtxt,
-                        outer_span: Span,
+                        trait_span: Span,
                         outer_pat_ident: Ident,
                         fields: &StaticFields,
                         getarg: |Span, @str, uint| -> @Expr)
                         -> @Expr {
     match *fields {
         Unnamed(ref fields) => {
             if fields.is_empty() {
-                cx.expr_ident(outer_span, outer_pat_ident)
+                cx.expr_ident(trait_span, outer_pat_ident)
             } else {
                 let fields = fields.iter().enumerate().map(|(i, &span)| {
                     getarg(span, format!("_field{}", i).to_managed(), i)
                 }).collect();
 
-                cx.expr_call_ident(outer_span, outer_pat_ident, fields)
+                cx.expr_call_ident(trait_span, outer_pat_ident, fields)
             }
         }
         Named(ref fields) => {
             // use the field's span to get nicer error messages.
             let fields = fields.iter().enumerate().map(|(i, &(name, span))| {
                 cx.field_imm(span, name, getarg(span, cx.str_of(name), i))
             }).collect();
-            cx.expr_struct_ident(outer_span, outer_pat_ident, fields)
+            cx.expr_struct_ident(trait_span, outer_pat_ident, fields)
         }
     }
 }

src/libsyntax/ext/deriving/default.rs

@@ -41,7 +41,7 @@ pub fn expand_deriving_default(cx: &ExtCtxt,
     trait_def.expand(mitem, in_items)
 }
 
-fn default_substructure(cx: &ExtCtxt, span: Span, substr: &Substructure) -> @Expr {
+fn default_substructure(cx: &ExtCtxt, trait_span: Span, substr: &Substructure) -> @Expr {
     let default_ident = ~[
         cx.ident_of("std"),
         cx.ident_of("default"),
@@ -55,25 +55,25 @@ fn default_substructure(cx: &ExtCtxt, span: Span, substr: &Substructure) -> @Exp
             match *summary {
                 Unnamed(ref fields) => {
                     if fields.is_empty() {
-                        cx.expr_ident(span, substr.type_ident)
+                        cx.expr_ident(trait_span, substr.type_ident)
                     } else {
                         let exprs = fields.map(|sp| default_call(*sp));
-                        cx.expr_call_ident(span, substr.type_ident, exprs)
+                        cx.expr_call_ident(trait_span, substr.type_ident, exprs)
                     }
                 }
                 Named(ref fields) => {
                     let default_fields = fields.map(|&(ident, span)| {
                         cx.field_imm(span, ident, default_call(span))
                     });
-                    cx.expr_struct_ident(span, substr.type_ident, default_fields)
+                    cx.expr_struct_ident(trait_span, substr.type_ident, default_fields)
                 }
             }
         }
         StaticEnum(..) => {
-            cx.span_err(span, "`Default` cannot be derived for enums, only structs");
+            cx.span_err(trait_span, "`Default` cannot be derived for enums, only structs");
             // let compilation continue
-            cx.expr_uint(span, 0)
+            cx.expr_uint(trait_span, 0)
         }
-        _ => cx.bug("Non-static method in `deriving(Default)`")
+        _ => cx.span_bug(trait_span, "Non-static method in `deriving(Default)`")
     };
 }