Split out the bad_style lints into a new module

Part of #22206

Author: wesleywiser

src/librustc_lint/bad_style.rs

@@ -0,0 +1,372 @@
+// Copyright 2015 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.
+
+use middle::def;
+use middle::def_id::DefId;
+use middle::ty;
+use lint::{LateContext, LintContext, LintArray};
+use lint::{LintPass, LateLintPass};
+
+use syntax::ast;
+use syntax::attr::{self, AttrMetaMethods};
+use syntax::codemap::Span;
+
+use rustc_front::hir;
+use rustc_front::visit::FnKind;
+
+#[derive(PartialEq)]
+pub enum MethodLateContext {
+    TraitDefaultImpl,
+    TraitImpl,
+    PlainImpl
+}
+
+pub fn method_context(cx: &LateContext, id: ast::NodeId, span: Span) -> MethodLateContext {
+    match cx.tcx.impl_or_trait_items.borrow().get(&DefId::local(id)) {
+        None => cx.sess().span_bug(span, "missing method descriptor?!"),
+        Some(item) => match item.container() {
+            ty::TraitContainer(..) => MethodLateContext::TraitDefaultImpl,
+            ty::ImplContainer(cid) => {
+                match cx.tcx.impl_trait_ref(cid) {
+                    Some(_) => MethodLateContext::TraitImpl,
+                    None => MethodLateContext::PlainImpl
+                }
+            }
+        }
+    }
+}
+
+declare_lint! {
+    pub NON_CAMEL_CASE_TYPES,
+    Warn,
+    "types, variants, traits and type parameters should have camel case names"
+}
+
+#[derive(Copy, Clone)]
+pub struct NonCamelCaseTypes;
+
+impl NonCamelCaseTypes {
+    fn check_case(&self, cx: &LateContext, sort: &str, ident: ast::Ident, span: Span) {
+        fn is_camel_case(ident: ast::Ident) -> bool {
+            let ident = ident.name.as_str();
+            if ident.is_empty() {
+                return true;
+            }
+            let ident = ident.trim_matches('_');
+
+            // start with a non-lowercase letter rather than non-uppercase
+            // ones (some scripts don't have a concept of upper/lowercase)
+            !ident.is_empty() && !ident.char_at(0).is_lowercase() && !ident.contains('_')
+        }
+
+        fn to_camel_case(s: &str) -> String {
+            s.split('_').flat_map(|word| word.chars().enumerate().map(|(i, c)|
+                if i == 0 {
+                    c.to_uppercase().collect::<String>()
+                } else {
+                    c.to_lowercase().collect()
+                }
+            )).collect::<Vec<_>>().concat()
+        }
+
+        let s = ident.name.as_str();
+
+        if !is_camel_case(ident) {
+            let c = to_camel_case(&s);
+            let m = if c.is_empty() {
+                format!("{} `{}` should have a camel case name such as `CamelCase`", sort, s)
+            } else {
+                format!("{} `{}` should have a camel case name such as `{}`", sort, s, c)
+            };
+            cx.span_lint(NON_CAMEL_CASE_TYPES, span, &m[..]);
+        }
+    }
+}
+
+impl LintPass for NonCamelCaseTypes {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(NON_CAMEL_CASE_TYPES)
+    }
+}
+
+impl LateLintPass for NonCamelCaseTypes {
+    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+        let extern_repr_count = it.attrs.iter().filter(|attr| {
+            attr::find_repr_attrs(cx.tcx.sess.diagnostic(), attr).iter()
+                .any(|r| r == &attr::ReprExtern)
+        }).count();
+        let has_extern_repr = extern_repr_count > 0;
+
+        if has_extern_repr {
+            return;
+        }
+
+        match it.node {
+            hir::ItemTy(..) | hir::ItemStruct(..) => {
+                self.check_case(cx, "type", it.ident, it.span)
+            }
+            hir::ItemTrait(..) => {
+                self.check_case(cx, "trait", it.ident, it.span)
+            }
+            hir::ItemEnum(ref enum_definition, _) => {
+                if has_extern_repr {
+                    return;
+                }
+                self.check_case(cx, "type", it.ident, it.span);
+                for variant in &enum_definition.variants {
+                    self.check_case(cx, "variant", variant.node.name, variant.span);
+                }
+            }
+            _ => ()
+        }
+    }
+
+    fn check_generics(&mut self, cx: &LateContext, it: &hir::Generics) {
+        for gen in it.ty_params.iter() {
+            self.check_case(cx, "type parameter", gen.ident, gen.span);
+        }
+    }
+}
+
+declare_lint! {
+    pub NON_SNAKE_CASE,
+    Warn,
+    "methods, functions, lifetime parameters and modules should have snake case names"
+}
+
+#[derive(Copy, Clone)]
+pub struct NonSnakeCase;
+
+impl NonSnakeCase {
+    fn to_snake_case(mut str: &str) -> String {
+        let mut words = vec![];
+        // Preserve leading underscores
+        str = str.trim_left_matches(|c: char| {
+            if c == '_' {
+                words.push(String::new());
+                true
+            } else {
+                false
+            }
+        });
+        for s in str.split('_') {
+            let mut last_upper = false;
+            let mut buf = String::new();
+            if s.is_empty() {
+                continue;
+            }
+            for ch in s.chars() {
+                if !buf.is_empty() && buf != "'"
+                                   && ch.is_uppercase()
+                                   && !last_upper {
+                    words.push(buf);
+                    buf = String::new();
+                }
+                last_upper = ch.is_uppercase();
+                buf.extend(ch.to_lowercase());
+            }
+            words.push(buf);
+        }
+        words.join("_")
+    }
+
+    fn check_snake_case(&self, cx: &LateContext, sort: &str, name: &str, span: Option<Span>) {
+        fn is_snake_case(ident: &str) -> bool {
+            if ident.is_empty() {
+                return true;
+            }
+            let ident = ident.trim_left_matches('\'');
+            let ident = ident.trim_matches('_');
+
+            let mut allow_underscore = true;
+            ident.chars().all(|c| {
+                allow_underscore = match c {
+                    '_' if !allow_underscore => return false,
+                    '_' => false,
+                    // It would be more obvious to use `c.is_lowercase()`,
+                    // but some characters do not have a lowercase form
+                    c if !c.is_uppercase() => true,
+                    _ => return false,
+                };
+                true
+            })
+        }
+
+        if !is_snake_case(name) {
+            let sc = NonSnakeCase::to_snake_case(name);
+            let msg = if sc != name {
+                format!("{} `{}` should have a snake case name such as `{}`",
+                        sort, name, sc)
+            } else {
+                format!("{} `{}` should have a snake case name",
+                        sort, name)
+            };
+            match span {
+                Some(span) => cx.span_lint(NON_SNAKE_CASE, span, &msg),
+                None => cx.lint(NON_SNAKE_CASE, &msg),
+            }
+        }
+    }
+}
+
+impl LintPass for NonSnakeCase {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(NON_SNAKE_CASE)
+    }
+}
+
+impl LateLintPass for NonSnakeCase {
+    fn check_crate(&mut self, cx: &LateContext, cr: &hir::Crate) {
+        let attr_crate_name = cr.attrs.iter().find(|at| at.check_name("crate_name"))
+                                      .and_then(|at| at.value_str().map(|s| (at, s)));
+        if let Some(ref name) = cx.tcx.sess.opts.crate_name {
+            self.check_snake_case(cx, "crate", name, None);
+        } else if let Some((attr, ref name)) = attr_crate_name {
+            self.check_snake_case(cx, "crate", name, Some(attr.span));
+        }
+    }
+
+    fn check_fn(&mut self, cx: &LateContext,
+                fk: FnKind, _: &hir::FnDecl,
+                _: &hir::Block, span: Span, id: ast::NodeId) {
+        match fk {
+            FnKind::Method(ident, _, _) => match method_context(cx, id, span) {
+                MethodLateContext::PlainImpl => {
+                    self.check_snake_case(cx, "method", &ident.name.as_str(), Some(span))
+                },
+                MethodLateContext::TraitDefaultImpl => {
+                    self.check_snake_case(cx, "trait method", &ident.name.as_str(), Some(span))
+                },
+                _ => (),
+            },
+            FnKind::ItemFn(ident, _, _, _, _, _) => {
+                self.check_snake_case(cx, "function", &ident.name.as_str(), Some(span))
+            },
+            _ => (),
+        }
+    }
+
+    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+        if let hir::ItemMod(_) = it.node {
+            self.check_snake_case(cx, "module", &it.ident.name.as_str(), Some(it.span));
+        }
+    }
+
+    fn check_trait_item(&mut self, cx: &LateContext, trait_item: &hir::TraitItem) {
+        if let hir::MethodTraitItem(_, None) = trait_item.node {
+            self.check_snake_case(cx, "trait method", &trait_item.ident.name.as_str(),
+                                  Some(trait_item.span));
+        }
+    }
+
+    fn check_lifetime_def(&mut self, cx: &LateContext, t: &hir::LifetimeDef) {
+        self.check_snake_case(cx, "lifetime", &t.lifetime.name.as_str(),
+                              Some(t.lifetime.span));
+    }
+
+    fn check_pat(&mut self, cx: &LateContext, p: &hir::Pat) {
+        if let &hir::PatIdent(_, ref path1, _) = &p.node {
+            let def = cx.tcx.def_map.borrow().get(&p.id).map(|d| d.full_def());
+            if let Some(def::DefLocal(_)) = def {
+                self.check_snake_case(cx, "variable", &path1.node.name.as_str(), Some(p.span));
+            }
+        }
+    }
+
+    fn check_struct_def(&mut self, cx: &LateContext, s: &hir::StructDef,
+                        _: ast::Ident, _: &hir::Generics, _: ast::NodeId) {
+        for sf in &s.fields {
+            if let hir::StructField_ { kind: hir::NamedField(ident, _), .. } = sf.node {
+                self.check_snake_case(cx, "structure field", &ident.name.as_str(),
+                                      Some(sf.span));
+            }
+        }
+    }
+}
+
+declare_lint! {
+    pub NON_UPPER_CASE_GLOBALS,
+    Warn,
+    "static constants should have uppercase identifiers"
+}
+
+#[derive(Copy, Clone)]
+pub struct NonUpperCaseGlobals;
+
+impl NonUpperCaseGlobals {
+    fn check_upper_case(cx: &LateContext, sort: &str, ident: ast::Ident, span: Span) {
+        let s = ident.name.as_str();
+
+        if s.chars().any(|c| c.is_lowercase()) {
+            let uc = NonSnakeCase::to_snake_case(&s).to_uppercase();
+            if uc != &s[..] {
+                cx.span_lint(NON_UPPER_CASE_GLOBALS, span,
+                    &format!("{} `{}` should have an upper case name such as `{}`",
+                             sort, s, uc));
+            } else {
+                cx.span_lint(NON_UPPER_CASE_GLOBALS, span,
+                    &format!("{} `{}` should have an upper case name",
+                             sort, s));
+            }
+        }
+    }
+}
+
+impl LintPass for NonUpperCaseGlobals {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(NON_UPPER_CASE_GLOBALS)
+    }
+}
+
+impl LateLintPass for NonUpperCaseGlobals {
+    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+        match it.node {
+            // only check static constants
+            hir::ItemStatic(_, hir::MutImmutable, _) => {
+                NonUpperCaseGlobals::check_upper_case(cx, "static constant", it.ident, it.span);
+            }
+            hir::ItemConst(..) => {
+                NonUpperCaseGlobals::check_upper_case(cx, "constant", it.ident, it.span);
+            }
+            _ => {}
+        }
+    }
+
+    fn check_trait_item(&mut self, cx: &LateContext, ti: &hir::TraitItem) {
+        match ti.node {
+            hir::ConstTraitItem(..) => {
+                NonUpperCaseGlobals::check_upper_case(cx, "associated constant",
+                                                      ti.ident, ti.span);
+            }
+            _ => {}
+        }
+    }
+
+    fn check_impl_item(&mut self, cx: &LateContext, ii: &hir::ImplItem) {
+        match ii.node {
+            hir::ConstImplItem(..) => {
+                NonUpperCaseGlobals::check_upper_case(cx, "associated constant",
+                                                      ii.ident, ii.span);
+            }
+            _ => {}
+        }
+    }
+
+    fn check_pat(&mut self, cx: &LateContext, p: &hir::Pat) {
+        // Lint for constants that look like binding identifiers (#7526)
+        match (&p.node, cx.tcx.def_map.borrow().get(&p.id).map(|d| d.full_def())) {
+            (&hir::PatIdent(_, ref path1, _), Some(def::DefConst(..))) => {
+                NonUpperCaseGlobals::check_upper_case(cx, "constant in pattern",
+                                                      path1.node, p.span);
+            }
+            _ => {}
+        }
+    }
+}