auto merge of #9638 : pnkfelix/rust/fsk-issue7526-attempt-to-catch-nonuc-statics-in-match-patterns, r=alexcrichton

r? anyone

Address scariest part of #7526 by adding a new more specific lint (that is set to warn by default, rather than allow).

Author: bors

src/librustc/lib/llvm.rs

@@ -11,6 +11,7 @@
 // LLVM wrappers are intended to be called from trans,
 // which already runs in a #[fixed_stack_segment]
 #[allow(cstack)];
+#[allow(non_uppercase_pattern_statics)];
 
 use std::c_str::ToCStr;
 use std::hashmap::HashMap;

src/librustc/middle/check_match.rs

@@ -133,6 +133,7 @@ pub fn check_arms(cx: &MatchCheckCtxt, arms: &[Arm]) {
                     _ => false
                 }
             };
+
             do walk_pat(*pat) |p| {
                 if pat_matches_nan(p) {
                     cx.tcx.sess.span_warn(p.span, "unmatchable NaN in pattern, \

src/librustc/middle/lint.rs

@@ -83,6 +83,7 @@ pub enum lint {
     unrecognized_lint,
     non_camel_case_types,
     non_uppercase_statics,
+    non_uppercase_pattern_statics,
     type_limits,
     unused_unsafe,
 
@@ -209,6 +210,13 @@ static lint_table: &'static [(&'static str, LintSpec)] = &[
          default: allow
      }),
 
+    ("non_uppercase_pattern_statics",
+     LintSpec {
+         lint: non_uppercase_pattern_statics,
+         desc: "static constants in match patterns should be all caps",
+         default: warn
+     }),
+
     ("managed_heap_memory",
      LintSpec {
         lint: managed_heap_memory,
@@ -1110,6 +1118,22 @@ fn check_item_non_uppercase_statics(cx: &Context, it: &ast::item) {
     }
 }
 
+fn check_pat_non_uppercase_statics(cx: &Context, p: &ast::Pat) {
+    // Lint for constants that look like binding identifiers (#7526)
+    match (&p.node, cx.tcx.def_map.find(&p.id)) {
+        (&ast::PatIdent(_, ref path, _), Some(&ast::DefStatic(_, false))) => {
+            // last identifier alone is right choice for this lint.
+            let ident = path.segments.last().identifier;
+            let s = cx.tcx.sess.str_of(ident);
+            if s.iter().any(|c| c.is_lowercase()) {
+                cx.span_lint(non_uppercase_pattern_statics, path.span,
+                             "static constant in pattern should be all caps");
+            }
+        }
+        _ => {}
+    }
+}
+
 struct UnusedUnsafeLintVisitor { stopping_on_items: bool }
 
 impl SubitemStoppableVisitor for UnusedUnsafeLintVisitor {
@@ -1516,6 +1540,11 @@ struct LintCheckVisitor;
 
 impl Visitor<@mut Context> for LintCheckVisitor {
 
+    fn visit_pat(&mut self, p:@ast::Pat, cx: @mut Context) {
+        check_pat_non_uppercase_statics(cx, p);
+        visit::walk_pat(self, p, cx);
+    }
+
     fn visit_item(&mut self, it:@ast::item, cx: @mut Context) {
 
                 do cx.with_lint_attrs(it.attrs) {

src/librustc/middle/trans/cabi_arm.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[allow(non_uppercase_pattern_statics)];
+
 use lib::llvm::{llvm, Integer, Pointer, Float, Double, Struct, Array};
 use lib::llvm::{Attribute, StructRetAttribute};
 use middle::trans::cabi::{FnType, LLVMType};

src/librustc/middle/trans/cabi_mips.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[allow(non_uppercase_pattern_statics)];
 
 use std::libc::c_uint;
 use std::num;

src/librustc/middle/trans/cabi_x86_64.rs

@@ -11,6 +11,8 @@
 // The classification code for the x86_64 ABI is taken from the clay language
 // https://github.com/jckarter/clay/blob/master/compiler/src/externals.cpp
 
+#[allow(non_uppercase_pattern_statics)];
+
 use lib::llvm::{llvm, Integer, Pointer, Float, Double};
 use lib::llvm::{Struct, Array, Attribute};
 use lib::llvm::{StructRetAttribute, ByValAttribute};

src/librustc/middle/trans/intrinsic.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[allow(non_uppercase_pattern_statics)];
+
 use back::{abi};
 use lib::llvm::{SequentiallyConsistent, Acquire, Release, Xchg};
 use lib::llvm::{ValueRef, Pointer};

src/librustc/middle/trans/type_.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[allow(non_uppercase_pattern_statics)];
 
 use lib::llvm::{llvm, TypeRef, Bool, False, True, TypeKind};
 use lib::llvm::{Float, Double, X86_FP80, PPC_FP128, FP128};

src/libstd/num/f32.rs

@@ -11,6 +11,7 @@
 //! Operations and constants for `f32`
 #[allow(missing_doc)];
 #[allow(non_uppercase_statics)];
+#[allow(non_uppercase_pattern_statics)];
 
 use default::Default;
 use libc::c_int;

src/libstd/num/f64.rs

@@ -12,6 +12,7 @@
 
 #[allow(missing_doc)];
 #[allow(non_uppercase_statics)];
+#[allow(non_uppercase_pattern_statics)];
 
 use default::Default;
 use libc::c_int;

src/test/compile-fail/issue-6804.rs

@@ -1,3 +1,5 @@
+#[allow(non_uppercase_pattern_statics)];
+
 // Matching against NaN should result in a warning
 
 use std::f64::NaN;

src/test/compile-fail/match-static-const-lc.rs

@@ -0,0 +1,58 @@
+// Copyright 2012-2013 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.
+
+// Issue #7526: lowercase static constants in patterns look like bindings
+
+#[deny(non_uppercase_pattern_statics)];
+
+pub static a : int = 97;
+
+fn f() {
+    let r = match (0,0) {
+        (0, a) => 0,
+        //~^ ERROR static constant in pattern should be all caps
+        (x, y) => 1 + x + y,
+    };
+    assert!(r == 1);
+}
+
+mod m {
+    pub static aha : int = 7;
+}
+
+fn g() {
+    use self::m::aha;
+    let r = match (0,0) {
+        (0, aha) => 0,
+        //~^ ERROR static constant in pattern should be all caps
+        (x, y)   => 1 + x + y,
+    };
+    assert!(r == 1);
+}
+
+mod n {
+    pub static OKAY : int = 8;
+}
+
+fn h() {
+    use not_okay = self::n::OKAY;
+    let r = match (0,0) {
+        (0, not_okay) => 0,
+        //~^ ERROR static constant in pattern should be all caps
+        (x, y)   => 1 + x + y,
+    };
+    assert!(r == 1);
+}
+
+fn main () {
+    f();
+    g();
+    h();
+}

src/test/run-pass/match-static-const-rename.rs

@@ -0,0 +1,71 @@
+// Copyright 2012-2013 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.
+
+// Issue #7526: lowercase static constants in patterns look like bindings
+
+// This is similar to compile-fail/match-static-const-lc, except it
+// shows the expected usual workaround (choosing a different name for
+// the static definition) and also demonstrates that one can work
+// around this problem locally by renaming the constant in the `use`
+// form to an uppercase identifier that placates the lint.
+
+#[deny(non_uppercase_pattern_statics)];
+
+pub static A : int = 97;
+
+fn f() {
+    let r = match (0,0) {
+        (0, A) => 0,
+        (x, y) => 1 + x + y,
+    };
+    assert!(r == 1);
+    let r = match (0,97) {
+        (0, A) => 0,
+        (x, y) => 1 + x + y,
+    };
+    assert!(r == 0);
+}
+
+mod m {
+    pub static aha : int = 7;
+}
+
+fn g() {
+    use AHA = self::m::aha;
+    let r = match (0,0) {
+        (0, AHA) => 0,
+        (x, y)   => 1 + x + y,
+    };
+    assert!(r == 1);
+    let r = match (0,7) {
+        (0, AHA) => 0,
+        (x, y)   => 1 + x + y,
+    };
+    assert!(r == 0);
+}
+
+fn h() {
+    let r = match (0,0) {
+        (0, self::m::aha) => 0,
+        (x, y)      => 1 + x + y,
+    };
+    assert!(r == 1);
+    let r = match (0,7) {
+        (0, self::m::aha) => 0,
+        (x, y)      => 1 + x + y,
+    };
+    assert!(r == 0);
+}
+
+pub fn main () {
+    f();
+    g();
+    h();
+}