Merge #3366

3366: Don't expand macros in some suggestions r=oli-obk a=phansch

Fixes #1148 
Fixes #1628
Fixes #2455
Fixes #3023
Fixes #3333
Fixes #3360

Co-authored-by: Philipp Hansch <[email protected]>

Author: bors[bot]

clippy_lints/src/identity_conversion.rs

@@ -12,7 +12,7 @@ use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
 use crate::rustc::{declare_tool_lint, lint_array};
 use crate::rustc::hir::*;
 use crate::syntax::ast::NodeId;
-use crate::utils::{in_macro, match_def_path, match_trait_method, same_tys, snippet, span_lint_and_then};
+use crate::utils::{in_macro, match_def_path, match_trait_method, same_tys, snippet, snippet_with_macro_callsite, span_lint_and_then};
 use crate::utils::{opt_def_id, paths, resolve_node};
 use crate::rustc_errors::Applicability;
 
@@ -72,7 +72,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for IdentityConversion {
                     let a = cx.tables.expr_ty(e);
                     let b = cx.tables.expr_ty(&args[0]);
                     if same_tys(cx, a, b) {
-                        let sugg = snippet(cx, args[0].span, "<expr>").into_owned();
+                        let sugg = snippet_with_macro_callsite(cx, args[0].span, "<expr>").to_string();
+
                         span_lint_and_then(cx, IDENTITY_CONVERSION, e.span, "identical conversion", |db| {
                             db.span_suggestion_with_applicability(
                                 e.span,

clippy_lints/src/matches.rs

@@ -19,7 +19,8 @@ use crate::syntax::ast::LitKind;
 use crate::syntax::source_map::Span;
 use crate::utils::paths;
 use crate::utils::{expr_block, is_allowed, is_expn_of, match_qpath, match_type, multispan_sugg,
-            remove_blocks, snippet, span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty};
+            remove_blocks, snippet, span_lint_and_sugg, span_lint_and_then,
+            span_note_and_lint, walk_ptrs_ty};
 use crate::utils::sugg::Sugg;
 use crate::consts::{constant, Constant};
 use crate::rustc_errors::Applicability;

clippy_lints/src/methods/mod.rs

@@ -21,7 +21,7 @@ use crate::utils::sugg;
 use crate::utils::{
     get_arg_name, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self, is_self_ty,
     iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method, match_type,
-    match_var, method_chain_args, remove_blocks, return_ty, same_tys, single_segment_path, snippet, span_lint,
+    match_var, method_chain_args, remove_blocks, return_ty, same_tys, single_segment_path, snippet, snippet_with_macro_callsite, span_lint,
     span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq,
 };
 use if_chain::if_chain;
@@ -1062,9 +1062,9 @@ fn lint_or_fun_call(cx: &LateContext<'_, '_>, expr: &hir::Expr, method_span: Spa
         }
 
         let sugg: Cow<'_, _> = match (fn_has_arguments, !or_has_args) {
-            (true, _) => format!("|_| {}", snippet(cx, arg.span, "..")).into(),
-            (false, false) => format!("|| {}", snippet(cx, arg.span, "..")).into(),
-            (false, true) => snippet(cx, fun_span, ".."),
+            (true, _) => format!("|_| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
+            (false, false) => format!("|| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
+            (false, true) => snippet_with_macro_callsite(cx, fun_span, ".."),
         };
         let span_replace_word = method_span.with_hi(span.hi());
         span_lint_and_sugg(

clippy_lints/src/utils/mod.rs

@@ -362,6 +362,12 @@ pub fn snippet<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str)
     snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
 }
 
+/// Same as `snippet`, but should only be used when it's clear that the input span is
+/// not a macro argument.
+pub fn snippet_with_macro_callsite<'a, 'b, T: LintContext<'b>>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
+    snippet(cx, span.source_callsite(), default)
+}
+
 /// Convert a span to a code snippet. Returns `None` if not available.
 pub fn snippet_opt<'a, T: LintContext<'a>>(cx: &T, span: Span) -> Option<String> {
     cx.sess().source_map().span_to_snippet(span).ok()
@@ -400,7 +406,10 @@ pub fn expr_block<'a, 'b, T: LintContext<'b>>(
 ) -> Cow<'a, str> {
     let code = snippet_block(cx, expr.span, default);
     let string = option.unwrap_or_default();
-    if let ExprKind::Block(_, _) = expr.node {
+    if in_macro(expr.span) {
+        Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
+    }
+    else if let ExprKind::Block(_, _) = expr.node {
         Cow::Owned(format!("{}{}", code, string))
     } else if string.is_empty() {
         Cow::Owned(format!("{{ {} }}", code))

tests/ui/identity_conversion.rs

@@ -53,4 +53,5 @@ fn main() {
     let _ = String::from(format!("A: {:04}", 123));
     let _ = "".lines().into_iter();
     let _ = vec![1, 2, 3].into_iter().into_iter();
+    let _: String = format!("Hello {}", "world").into();
 }

tests/ui/identity_conversion.stderr

@@ -58,5 +58,11 @@ error: identical conversion
 55 |     let _ = vec![1, 2, 3].into_iter().into_iter();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into_iter()`: `vec![1, 2, 3].into_iter()`
 
-error: aborting due to 9 previous errors
+error: identical conversion
+  --> $DIR/identity_conversion.rs:56:21
+   |
+56 |     let _: String = format!("Hello {}", "world").into();
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into()`: `format!("Hello {}", "world")`
+
+error: aborting due to 10 previous errors
 

tests/ui/matches.stderr

@@ -33,7 +33,7 @@ error: you seem to be trying to use match for destructuring a single pattern. Co
 51 | |         &(v, 1) => println!("{}", v),
 52 | |         _ => println!("none"),
 53 | |     }
-   | |_____^ help: try this: `if let &(v, 1) = tup { $ crate :: io :: _print ( format_args_nl ! ( $ ( $ arg ) * ) ) ; } else { $ crate :: io :: _print ( format_args_nl ! ( $ ( $ arg ) * ) ) ; }`
+   | |_____^ help: try this: `if let &(v, 1) = tup { println!("{}", v) } else { println!("none") }`
 
 error: you don't need to add `&` to all patterns
   --> $DIR/matches.rs:50:5

tests/ui/methods.stderr

@@ -297,7 +297,7 @@ error: use of `unwrap_or` followed by a function call
    --> $DIR/methods.rs:339:14
     |
 339 |     with_vec.unwrap_or(vec![]);
-    |              ^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| < [ _ ] > :: into_vec ( box [ $ ( $ x ) , * ] ))`
+    |              ^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| vec![])`
 
 error: use of `unwrap_or` followed by a function call
    --> $DIR/methods.rs:344:21

tests/ui/single_match.rs

@@ -23,6 +23,15 @@ fn single_match(){
         _ => ()
     };
 
+    let x = Some(1u8);
+    match x {
+        // Note the missing block braces.
+        // We suggest `if let Some(y) = x { .. }` because the macro
+        // is expanded before we can do anything.
+        Some(y) => println!("{:?}", y),
+        _ => ()
+    }
+
     let z = (1u8,1u8);
     match z {
         (2...3, 7...9) => dummy(),

tests/ui/single_match.stderr

@@ -12,38 +12,50 @@ error: you seem to be trying to use match for destructuring a single pattern. Co
 error: you seem to be trying to use match for destructuring a single pattern. Consider using `if let`
   --> $DIR/single_match.rs:27:5
    |
-27 | /     match z {
-28 | |         (2...3, 7...9) => dummy(),
-29 | |         _ => {}
-30 | |     };
+27 | /     match x {
+28 | |         // Note the missing block braces.
+29 | |         // We suggest `if let Some(y) = x { .. }` because the macro
+30 | |         // is expanded before we can do anything.
+31 | |         Some(y) => println!("{:?}", y),
+32 | |         _ => ()
+33 | |     }
+   | |_____^ help: try this: `if let Some(y) = x { println!("{:?}", y) }`
+
+error: you seem to be trying to use match for destructuring a single pattern. Consider using `if let`
+  --> $DIR/single_match.rs:36:5
+   |
+36 | /     match z {
+37 | |         (2...3, 7...9) => dummy(),
+38 | |         _ => {}
+39 | |     };
    | |_____^ help: try this: `if let (2...3, 7...9) = z { dummy() }`
 
 error: you seem to be trying to use match for destructuring a single pattern. Consider using `if let`
-  --> $DIR/single_match.rs:53:5
+  --> $DIR/single_match.rs:62:5
    |
-53 | /     match x {
-54 | |         Some(y) => dummy(),
-55 | |         None => ()
-56 | |     };
+62 | /     match x {
+63 | |         Some(y) => dummy(),
+64 | |         None => ()
+65 | |     };
    | |_____^ help: try this: `if let Some(y) = x { dummy() }`
 
 error: you seem to be trying to use match for destructuring a single pattern. Consider using `if let`
-  --> $DIR/single_match.rs:58:5
+  --> $DIR/single_match.rs:67:5
    |
-58 | /     match y {
-59 | |         Ok(y) => dummy(),
-60 | |         Err(..) => ()
-61 | |     };
+67 | /     match y {
+68 | |         Ok(y) => dummy(),
+69 | |         Err(..) => ()
+70 | |     };
    | |_____^ help: try this: `if let Ok(y) = y { dummy() }`
 
 error: you seem to be trying to use match for destructuring a single pattern. Consider using `if let`
-  --> $DIR/single_match.rs:65:5
+  --> $DIR/single_match.rs:74:5
    |
-65 | /     match c {
-66 | |         Cow::Borrowed(..) => dummy(),
-67 | |         Cow::Owned(..) => (),
-68 | |     };
+74 | /     match c {
+75 | |         Cow::Borrowed(..) => dummy(),
+76 | |         Cow::Owned(..) => (),
+77 | |     };
    | |_____^ help: try this: `if let Cow::Borrowed(..) = c { dummy() }`
 
-error: aborting due to 5 previous errors
+error: aborting due to 6 previous errors