]> git.lizzy.rs Git - rust.git/blobdiff - clippy_lints/src/utils/sugg.rs
Auto merge of #3705 - matthiaskrgr:rustup, r=phansch
[rust.git] / clippy_lints / src / utils / sugg.rs
index 11187559bf6ad58ca76d6fe00842bc0d232b3211..166470876c988fd718f9fccd0bb2950820feeb92 100644 (file)
@@ -1,21 +1,21 @@
 //! Contains utility functions to generate suggestions.
-#![deny(missing_docs_in_private_items)]
-// currently ignores lifetimes and generics
-#![allow(use_self)]
+#![deny(clippy::missing_docs_in_private_items)]
 
+use crate::utils::{higher, in_macro, snippet, snippet_opt};
 use matches::matches;
 use rustc::hir;
 use rustc::lint::{EarlyContext, LateContext, LintContext};
 use rustc_errors;
+use rustc_errors::Applicability;
+use std;
 use std::borrow::Cow;
+use std::convert::TryInto;
 use std::fmt::Display;
-use std;
-use syntax::codemap::{CharPos, Span};
+use syntax::ast;
 use syntax::parse::token;
 use syntax::print::pprust::token_to_string;
+use syntax::source_map::{CharPos, Span};
 use syntax::util::parser::AssocOp;
-use syntax::ast;
-use crate::utils::{higher, snippet, snippet_opt};
 use syntax_pos::{BytePos, Pos};
 
 /// A helper type to build suggestion correctly handling parenthesis.
@@ -40,37 +40,38 @@ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
     }
 }
 
-#[allow(wrong_self_convention)] // ok, because of the function `as_ty` method
+#[allow(clippy::wrong_self_convention)] // ok, because of the function `as_ty` method
 impl<'a> Sugg<'a> {
     /// Prepare a suggestion from an expression.
     pub fn hir_opt(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> Option<Self> {
         snippet_opt(cx, expr.span).map(|snippet| {
             let snippet = Cow::Owned(snippet);
             match expr.node {
-                hir::ExprKind::AddrOf(..) |
-                hir::ExprKind::Box(..) |
-                hir::ExprKind::Closure(.., _) |
-                hir::ExprKind::If(..) |
-                hir::ExprKind::Unary(..) |
-                hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
-                hir::ExprKind::Continue(..) |
-                hir::ExprKind::Yield(..) |
-                hir::ExprKind::Array(..) |
-                hir::ExprKind::Block(..) |
-                hir::ExprKind::Break(..) |
-                hir::ExprKind::Call(..) |
-                hir::ExprKind::Field(..) |
-                hir::ExprKind::Index(..) |
-                hir::ExprKind::InlineAsm(..) |
-                hir::ExprKind::Lit(..) |
-                hir::ExprKind::Loop(..) |
-                hir::ExprKind::MethodCall(..) |
-                hir::ExprKind::Path(..) |
-                hir::ExprKind::Repeat(..) |
-                hir::ExprKind::Ret(..) |
-                hir::ExprKind::Struct(..) |
-                hir::ExprKind::Tup(..) |
-                hir::ExprKind::While(..) => Sugg::NonParen(snippet),
+                hir::ExprKind::AddrOf(..)
+                | hir::ExprKind::Box(..)
+                | hir::ExprKind::Closure(.., _)
+                | hir::ExprKind::If(..)
+                | hir::ExprKind::Unary(..)
+                | hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
+                hir::ExprKind::Continue(..)
+                | hir::ExprKind::Yield(..)
+                | hir::ExprKind::Array(..)
+                | hir::ExprKind::Block(..)
+                | hir::ExprKind::Break(..)
+                | hir::ExprKind::Call(..)
+                | hir::ExprKind::Field(..)
+                | hir::ExprKind::Index(..)
+                | hir::ExprKind::InlineAsm(..)
+                | hir::ExprKind::Lit(..)
+                | hir::ExprKind::Loop(..)
+                | hir::ExprKind::MethodCall(..)
+                | hir::ExprKind::Path(..)
+                | hir::ExprKind::Repeat(..)
+                | hir::ExprKind::Ret(..)
+                | hir::ExprKind::Struct(..)
+                | hir::ExprKind::Tup(..)
+                | hir::ExprKind::While(..)
+                | hir::ExprKind::Err => Sugg::NonParen(snippet),
                 hir::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
                 hir::ExprKind::AssignOp(op, ..) => Sugg::BinOp(hirbinop2assignop(op), snippet),
                 hir::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(higher::binop(op.node)), snippet),
@@ -86,6 +87,30 @@ pub fn hir(cx: &LateContext<'_, '_>, expr: &hir::Expr, default: &'a str) -> Self
         Self::hir_opt(cx, expr).unwrap_or_else(|| Sugg::NonParen(Cow::Borrowed(default)))
     }
 
+    /// Same as `hir`, but it adapts the applicability level by following rules:
+    ///
+    /// - Applicability level `Unspecified` will never be changed.
+    /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
+    /// - If the default value is used and the applicability level is `MachineApplicable`, change it
+    ///   to
+    /// `HasPlaceholders`
+    pub fn hir_with_applicability(
+        cx: &LateContext<'_, '_>,
+        expr: &hir::Expr,
+        default: &'a str,
+        applicability: &mut Applicability,
+    ) -> Self {
+        if *applicability != Applicability::Unspecified && in_macro(expr.span) {
+            *applicability = Applicability::MaybeIncorrect;
+        }
+        Self::hir_opt(cx, expr).unwrap_or_else(|| {
+            if *applicability == Applicability::MachineApplicable {
+                *applicability = Applicability::HasPlaceholders;
+            }
+            Sugg::NonParen(Cow::Borrowed(default))
+        })
+    }
+
     /// Prepare a suggestion from an expression.
     pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self {
         use syntax::ast::RangeLimits;
@@ -93,39 +118,40 @@ pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self {
         let snippet = snippet(cx, expr.span, default);
 
         match expr.node {
-            ast::ExprKind::AddrOf(..) |
-            ast::ExprKind::Box(..) |
-            ast::ExprKind::Closure(..) |
-            ast::ExprKind::If(..) |
-            ast::ExprKind::IfLet(..) |
-            ast::ExprKind::ObsoleteInPlace(..) |
-            ast::ExprKind::Unary(..) |
-            ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
-            ast::ExprKind::Async(..) |
-            ast::ExprKind::Block(..) |
-            ast::ExprKind::Break(..) |
-            ast::ExprKind::Call(..) |
-            ast::ExprKind::Catch(..) |
-            ast::ExprKind::Continue(..) |
-            ast::ExprKind::Yield(..) |
-            ast::ExprKind::Field(..) |
-            ast::ExprKind::ForLoop(..) |
-            ast::ExprKind::Index(..) |
-            ast::ExprKind::InlineAsm(..) |
-            ast::ExprKind::Lit(..) |
-            ast::ExprKind::Loop(..) |
-            ast::ExprKind::Mac(..) |
-            ast::ExprKind::MethodCall(..) |
-            ast::ExprKind::Paren(..) |
-            ast::ExprKind::Path(..) |
-            ast::ExprKind::Repeat(..) |
-            ast::ExprKind::Ret(..) |
-            ast::ExprKind::Struct(..) |
-            ast::ExprKind::Try(..) |
-            ast::ExprKind::Tup(..) |
-            ast::ExprKind::Array(..) |
-            ast::ExprKind::While(..) |
-            ast::ExprKind::WhileLet(..) => Sugg::NonParen(snippet),
+            ast::ExprKind::AddrOf(..)
+            | ast::ExprKind::Box(..)
+            | ast::ExprKind::Closure(..)
+            | ast::ExprKind::If(..)
+            | ast::ExprKind::IfLet(..)
+            | ast::ExprKind::ObsoleteInPlace(..)
+            | ast::ExprKind::Unary(..)
+            | ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
+            ast::ExprKind::Async(..)
+            | ast::ExprKind::Block(..)
+            | ast::ExprKind::Break(..)
+            | ast::ExprKind::Call(..)
+            | ast::ExprKind::Continue(..)
+            | ast::ExprKind::Yield(..)
+            | ast::ExprKind::Field(..)
+            | ast::ExprKind::ForLoop(..)
+            | ast::ExprKind::Index(..)
+            | ast::ExprKind::InlineAsm(..)
+            | ast::ExprKind::Lit(..)
+            | ast::ExprKind::Loop(..)
+            | ast::ExprKind::Mac(..)
+            | ast::ExprKind::MethodCall(..)
+            | ast::ExprKind::Paren(..)
+            | ast::ExprKind::Path(..)
+            | ast::ExprKind::Repeat(..)
+            | ast::ExprKind::Ret(..)
+            | ast::ExprKind::Struct(..)
+            | ast::ExprKind::Try(..)
+            | ast::ExprKind::TryBlock(..)
+            | ast::ExprKind::Tup(..)
+            | ast::ExprKind::Array(..)
+            | ast::ExprKind::While(..)
+            | ast::ExprKind::WhileLet(..)
+            | ast::ExprKind::Err => Sugg::NonParen(snippet),
             ast::ExprKind::Range(.., RangeLimits::HalfOpen) => Sugg::BinOp(AssocOp::DotDot, snippet),
             ast::ExprKind::Range(.., RangeLimits::Closed) => Sugg::BinOp(AssocOp::DotDotEq, snippet),
             ast::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
@@ -141,6 +167,11 @@ pub fn and(self, rhs: &Self) -> Sugg<'static> {
         make_binop(ast::BinOpKind::And, &self, rhs)
     }
 
+    /// Convenience method to create the `<lhs> & <rhs>` suggestion.
+    pub fn bit_and(self, rhs: &Self) -> Sugg<'static> {
+        make_binop(ast::BinOpKind::BitAnd, &self, rhs)
+    }
+
     /// Convenience method to create the `<lhs> as <rhs>` suggestion.
     pub fn as_ty<R: Display>(self, rhs: R) -> Sugg<'static> {
         make_assoc(AssocOp::As, &self, &Sugg::NonParen(rhs.to_string().into()))
@@ -175,8 +206,20 @@ pub fn mut_addr_deref(self) -> Sugg<'static> {
         make_unop("&mut *", self)
     }
 
+    /// Convenience method to transform suggestion into a return call
+    pub fn make_return(self) -> Sugg<'static> {
+        Sugg::NonParen(Cow::Owned(format!("return {}", self)))
+    }
+
+    /// Convenience method to transform suggestion into a block
+    /// where the suggestion is a trailing expression
+    pub fn blockify(self) -> Sugg<'static> {
+        Sugg::NonParen(Cow::Owned(format!("{{ {} }}", self)))
+    }
+
     /// Convenience method to create the `<lhs>..<rhs>` or `<lhs>...<rhs>`
     /// suggestion.
+    #[allow(dead_code)]
     pub fn range(self, end: &Self, limit: ast::RangeLimits) -> Sugg<'static> {
         match limit {
             ast::RangeLimits::HalfOpen => make_assoc(AssocOp::DotDot, &self, end),
@@ -191,10 +234,12 @@ pub fn maybe_par(self) -> Self {
         match self {
             Sugg::NonParen(..) => self,
             // (x) and (x).y() both don't need additional parens
-            Sugg::MaybeParen(sugg) => if sugg.starts_with('(') && sugg.ends_with(')') {
-                Sugg::MaybeParen(sugg)
-            } else {
-                Sugg::NonParen(format!("({})", sugg).into())
+            Sugg::MaybeParen(sugg) => {
+                if sugg.starts_with('(') && sugg.ends_with(')') {
+                    Sugg::MaybeParen(sugg)
+                } else {
+                    Sugg::NonParen(format!("({})", sugg).into())
+                }
             },
             Sugg::BinOp(_, sugg) => Sugg::NonParen(format!("({})", sugg).into()),
         }
@@ -233,10 +278,7 @@ struct ParenHelper<T> {
 impl<T> ParenHelper<T> {
     /// Build a `ParenHelper`.
     fn new(paren: bool, wrapped: T) -> Self {
-        Self {
-            paren,
-            wrapped,
-        }
+        Self { paren, wrapped }
     }
 }
 
@@ -286,7 +328,8 @@ fn needs_paren(op: &AssocOp, other: &AssocOp, dir: Associativity) -> bool {
             || (other.precedence() == op.precedence()
                 && ((op != other && associativity(op) != dir)
                     || (op == other && associativity(op) != Associativity::Both)))
-            || is_shift(op) && is_arith(other) || is_shift(other) && is_arith(op)
+            || is_shift(op) && is_arith(other)
+            || is_shift(other) && is_arith(op)
     }
 
     let lhs_paren = if let Sugg::BinOp(ref lop, _) = *lhs {
@@ -304,24 +347,29 @@ fn needs_paren(op: &AssocOp, other: &AssocOp, dir: Associativity) -> bool {
     let lhs = ParenHelper::new(lhs_paren, lhs);
     let rhs = ParenHelper::new(rhs_paren, rhs);
     let sugg = match op {
-        AssocOp::Add |
-        AssocOp::BitAnd |
-        AssocOp::BitOr |
-        AssocOp::BitXor |
-        AssocOp::Divide |
-        AssocOp::Equal |
-        AssocOp::Greater |
-        AssocOp::GreaterEqual |
-        AssocOp::LAnd |
-        AssocOp::LOr |
-        AssocOp::Less |
-        AssocOp::LessEqual |
-        AssocOp::Modulus |
-        AssocOp::Multiply |
-        AssocOp::NotEqual |
-        AssocOp::ShiftLeft |
-        AssocOp::ShiftRight |
-        AssocOp::Subtract => format!("{} {} {}", lhs, op.to_ast_binop().expect("Those are AST ops").to_string(), rhs),
+        AssocOp::Add
+        | AssocOp::BitAnd
+        | AssocOp::BitOr
+        | AssocOp::BitXor
+        | AssocOp::Divide
+        | AssocOp::Equal
+        | AssocOp::Greater
+        | AssocOp::GreaterEqual
+        | AssocOp::LAnd
+        | AssocOp::LOr
+        | AssocOp::Less
+        | AssocOp::LessEqual
+        | AssocOp::Modulus
+        | AssocOp::Multiply
+        | AssocOp::NotEqual
+        | AssocOp::ShiftLeft
+        | AssocOp::ShiftRight
+        | AssocOp::Subtract => format!(
+            "{} {} {}",
+            lhs,
+            op.to_ast_binop().expect("Those are AST ops").to_string(),
+            rhs
+        ),
         AssocOp::Assign => format!("{} = {}", lhs, rhs),
         AssocOp::ObsoleteInPlace => format!("in ({}) {}", lhs, rhs),
         AssocOp::AssignOp(op) => format!("{} {}= {}", lhs, token_to_string(&token::BinOp(op)), rhs),
@@ -366,17 +414,8 @@ fn associativity(op: &AssocOp) -> Associativity {
     match *op {
         ObsoleteInPlace | Assign | AssignOp(_) => Associativity::Right,
         Add | BitAnd | BitOr | BitXor | LAnd | LOr | Multiply | As | Colon => Associativity::Both,
-        Divide |
-        Equal |
-        Greater |
-        GreaterEqual |
-        Less |
-        LessEqual |
-        Modulus |
-        NotEqual |
-        ShiftLeft |
-        ShiftRight |
-        Subtract => Associativity::Left,
+        Divide | Equal | Greater | GreaterEqual | Less | LessEqual | Modulus | NotEqual | ShiftLeft | ShiftRight
+        | Subtract => Associativity::Left,
         DotDot | DotDotEq => Associativity::None,
     }
 }
@@ -397,15 +436,14 @@ fn hirbinop2assignop(op: hir::BinOp) -> AssocOp {
         hir::BinOpKind::Shr => Shr,
         hir::BinOpKind::Sub => Minus,
 
-        hir::BinOpKind::And
+        hir::BinOpKind::And
         | hir::BinOpKind::Eq
         | hir::BinOpKind::Ge
         | hir::BinOpKind::Gt
         | hir::BinOpKind::Le
         | hir::BinOpKind::Lt
         | hir::BinOpKind::Ne
-        | hir::BinOpKind::Or
-        => panic!("This operator does not exist"),
+        | hir::BinOpKind::Or => panic!("This operator does not exist"),
     })
 }
 
@@ -432,10 +470,8 @@ fn astbinop2assignop(op: ast::BinOp) -> AssocOp {
 /// Return the indentation before `span` if there are nothing but `[ \t]`
 /// before it on its line.
 fn indentation<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
-    let lo = cx.sess().codemap().lookup_char_pos(span.lo());
-    if let Some(line) = lo.file
-        .get_line(lo.line - 1 /* line numbers in `Loc` are 1-based */)
-    {
+    let lo = cx.sess().source_map().lookup_char_pos(span.lo());
+    if let Some(line) = lo.file.get_line(lo.line - 1 /* line numbers in `Loc` are 1-based */) {
         if let Some((pos, _)) = line.char_indices().find(|&(_, c)| c != ' ' && c != '\t') {
             // we can mix char and byte positions here because we only consider `[ \t]`
             if lo.col == CharPos(pos) {
@@ -462,7 +498,14 @@ pub trait DiagnosticBuilderExt<'a, T: LintContext<'a>> {
     /// ```rust,ignore
     /// db.suggest_item_with_attr(cx, item, "#[derive(Default)]");
     /// ```
-    fn suggest_item_with_attr<D: Display + ?Sized>(&mut self, cx: &T, item: Span, msg: &str, attr: &D);
+    fn suggest_item_with_attr<D: Display + ?Sized>(
+        &mut self,
+        cx: &T,
+        item: Span,
+        msg: &str,
+        attr: &D,
+        applicability: Applicability,
+    );
 
     /// Suggest to add an item before another.
     ///
@@ -476,7 +519,7 @@ pub trait DiagnosticBuilderExt<'a, T: LintContext<'a>> {
     ///     bar();
     /// }");
     /// ```
-    fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str);
+    fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability);
 
     /// Suggest to completely remove an item.
     ///
@@ -489,19 +532,26 @@ pub trait DiagnosticBuilderExt<'a, T: LintContext<'a>> {
     /// ```rust,ignore
     /// db.suggest_remove_item(cx, item, "remove this")
     /// ```
-    fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str);
+    fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability);
 }
 
 impl<'a, 'b, 'c, T: LintContext<'c>> DiagnosticBuilderExt<'c, T> for rustc_errors::DiagnosticBuilder<'b> {
-    fn suggest_item_with_attr<D: Display + ?Sized>(&mut self, cx: &T, item: Span, msg: &str, attr: &D) {
+    fn suggest_item_with_attr<D: Display + ?Sized>(
+        &mut self,
+        cx: &T,
+        item: Span,
+        msg: &str,
+        attr: &D,
+        applicability: Applicability,
+    ) {
         if let Some(indent) = indentation(cx, item) {
             let span = item.with_hi(item.lo());
 
-            self.span_suggestion(span, msg, format!("{}\n{}", attr, indent));
+            self.span_suggestion(span, msg, format!("{}\n{}", attr, indent), applicability);
         }
     }
 
-    fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str) {
+    fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability) {
         if let Some(indent) = indentation(cx, item) {
             let span = item.with_hi(item.lo());
 
@@ -518,23 +568,42 @@ fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str
                 })
                 .collect::<String>();
 
-            self.span_suggestion(span, msg, format!("{}\n{}", new_item, indent));
+            self.span_suggestion(span, msg, format!("{}\n{}", new_item, indent), applicability);
         }
     }
 
-    fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str) {
+    fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability) {
         let mut remove_span = item;
-        let hi = cx.sess().codemap().next_point(remove_span).hi();
-        let fmpos = cx.sess().codemap().lookup_byte_offset(hi);
+        let hi = cx.sess().source_map().next_point(remove_span).hi();
+        let fmpos = cx.sess().source_map().lookup_byte_offset(hi);
 
-        if let Some(ref src) = fmpos.fm.src {
+        if let Some(ref src) = fmpos.sf.src {
             let non_whitespace_offset = src[fmpos.pos.to_usize()..].find(|c| c != ' ' && c != '\t' && c != '\n');
 
             if let Some(non_whitespace_offset) = non_whitespace_offset {
-                remove_span = remove_span.with_hi(remove_span.hi() + BytePos(non_whitespace_offset as u32))
+                remove_span = remove_span
+                    .with_hi(remove_span.hi() + BytePos(non_whitespace_offset.try_into().expect("offset too large")))
             }
         }
 
-        self.span_suggestion(remove_span, msg, String::new());
+        self.span_suggestion(remove_span, msg, String::new(), applicability);
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::Sugg;
+    use std::borrow::Cow;
+
+    const SUGGESTION: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("function_call()"));
+
+    #[test]
+    fn make_return_transform_sugg_into_a_return_call() {
+        assert_eq!("return function_call()", SUGGESTION.make_return().to_string());
+    }
+
+    #[test]
+    fn blockify_transforms_sugg_into_a_block() {
+        assert_eq!("{ function_call() }", SUGGESTION.blockify().to_string());
     }
 }