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1 //! Diagnostics rendering and fixits.
2 //!
3 //! Most of the diagnostics originate from the dark depth of the compiler, and
4 //! are originally expressed in term of IR. When we emit the diagnostic, we are
5 //! usually not in the position to decide how to best "render" it in terms of
6 //! user-authored source code. We are especially not in the position to offer
7 //! fixits, as the compiler completely lacks the infrastructure to edit the
8 //! source code.
9 //!
10 //! Instead, we "bubble up" raw, structured diagnostics until the `hir` crate,
11 //! where we "cook" them so that each diagnostic is formulated in terms of `hir`
12 //! types. Well, at least that's the aspiration, the "cooking" is somewhat
13 //! ad-hoc at the moment. Anyways, we get a bunch of ide-friendly diagnostic
14 //! structs from hir, and we want to render them to unified serializable
15 //! representation (span, level, message) here. If we can, we also provide
16 //! fixits. By the way, that's why we want to keep diagnostics structured
17 //! internally -- so that we have all the info to make fixes.
18 //!
19 //! We have one "handler" module per diagnostic code. Such a module contains
20 //! rendering, optional fixes and tests. It's OK if some low-level compiler
21 //! functionality ends up being tested via a diagnostic.
22 //!
23 //! There are also a couple of ad-hoc diagnostics implemented directly here, we
24 //! don't yet have a great pattern for how to do them properly.
25 
26 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
27 
28 mod handlers {
29     pub(crate) mod break_outside_of_loop;
30     pub(crate) mod expected_function;
31     pub(crate) mod inactive_code;
32     pub(crate) mod incoherent_impl;
33     pub(crate) mod incorrect_case;
34     pub(crate) mod invalid_derive_target;
35     pub(crate) mod macro_error;
36     pub(crate) mod malformed_derive;
37     pub(crate) mod mismatched_arg_count;
38     pub(crate) mod missing_fields;
39     pub(crate) mod missing_match_arms;
40     pub(crate) mod missing_unsafe;
41     pub(crate) mod moved_out_of_ref;
42     pub(crate) mod mutability_errors;
43     pub(crate) mod no_such_field;
44     pub(crate) mod private_assoc_item;
45     pub(crate) mod private_field;
46     pub(crate) mod replace_filter_map_next_with_find_map;
47     pub(crate) mod typed_hole;
48     pub(crate) mod type_mismatch;
49     pub(crate) mod unimplemented_builtin_macro;
50     pub(crate) mod unresolved_extern_crate;
51     pub(crate) mod unresolved_field;
52     pub(crate) mod unresolved_method;
53     pub(crate) mod unresolved_import;
54     pub(crate) mod unresolved_macro_call;
55     pub(crate) mod unresolved_module;
56     pub(crate) mod unresolved_proc_macro;
57     pub(crate) mod undeclared_label;
58     pub(crate) mod unreachable_label;
59 
60     // The handlers below are unusual, the implement the diagnostics as well.
61     pub(crate) mod field_shorthand;
62     pub(crate) mod useless_braces;
63     pub(crate) mod unlinked_file;
64     pub(crate) mod json_is_not_rust;
65 }
66 
67 #[cfg(test)]
68 mod tests;
69 
70 use hir::{diagnostics::AnyDiagnostic, InFile, Semantics};
71 use ide_db::{
72     assists::{Assist, AssistId, AssistKind, AssistResolveStrategy},
73     base_db::{FileId, FileRange, SourceDatabase},
74     imports::insert_use::InsertUseConfig,
75     label::Label,
76     source_change::SourceChange,
77     FxHashSet, RootDatabase,
78 };
79 use syntax::{algo::find_node_at_range, ast::AstNode, SyntaxNodePtr, TextRange};
80 
81 // FIXME: Make this an enum
82 #[derive(Copy, Clone, Debug, PartialEq)]
83 pub struct DiagnosticCode(pub &'static str);
84 
85 impl DiagnosticCode {
as_str(&self) -> &str86     pub fn as_str(&self) -> &str {
87         self.0
88     }
89 }
90 
91 #[derive(Debug)]
92 pub struct Diagnostic {
93     pub code: DiagnosticCode,
94     pub message: String,
95     pub range: TextRange,
96     pub severity: Severity,
97     pub unused: bool,
98     pub experimental: bool,
99     pub fixes: Option<Vec<Assist>>,
100 }
101 
102 impl Diagnostic {
new(code: &'static str, message: impl Into<String>, range: TextRange) -> Diagnostic103     fn new(code: &'static str, message: impl Into<String>, range: TextRange) -> Diagnostic {
104         let message = message.into();
105         Diagnostic {
106             code: DiagnosticCode(code),
107             message,
108             range,
109             severity: Severity::Error,
110             unused: false,
111             experimental: false,
112             fixes: None,
113         }
114     }
115 
experimental(mut self) -> Diagnostic116     fn experimental(mut self) -> Diagnostic {
117         self.experimental = true;
118         self
119     }
120 
severity(mut self, severity: Severity) -> Diagnostic121     fn severity(mut self, severity: Severity) -> Diagnostic {
122         self.severity = severity;
123         self
124     }
125 
with_fixes(mut self, fixes: Option<Vec<Assist>>) -> Diagnostic126     fn with_fixes(mut self, fixes: Option<Vec<Assist>>) -> Diagnostic {
127         self.fixes = fixes;
128         self
129     }
130 
with_unused(mut self, unused: bool) -> Diagnostic131     fn with_unused(mut self, unused: bool) -> Diagnostic {
132         self.unused = unused;
133         self
134     }
135 }
136 
137 #[derive(Debug, Copy, Clone)]
138 pub enum Severity {
139     Error,
140     // We don't actually emit this one yet, but we should at some point.
141     // Warning,
142     WeakWarning,
143 }
144 
145 #[derive(Clone, Debug, PartialEq, Eq)]
146 pub enum ExprFillDefaultMode {
147     Todo,
148     Default,
149 }
150 impl Default for ExprFillDefaultMode {
default() -> Self151     fn default() -> Self {
152         Self::Todo
153     }
154 }
155 
156 #[derive(Debug, Clone)]
157 pub struct DiagnosticsConfig {
158     pub proc_macros_enabled: bool,
159     pub proc_attr_macros_enabled: bool,
160     pub disable_experimental: bool,
161     pub disabled: FxHashSet<String>,
162     pub expr_fill_default: ExprFillDefaultMode,
163     // FIXME: We may want to include a whole `AssistConfig` here
164     pub insert_use: InsertUseConfig,
165     pub prefer_no_std: bool,
166 }
167 
168 impl DiagnosticsConfig {
test_sample() -> Self169     pub fn test_sample() -> Self {
170         use hir::PrefixKind;
171         use ide_db::imports::insert_use::ImportGranularity;
172 
173         Self {
174             proc_macros_enabled: Default::default(),
175             proc_attr_macros_enabled: Default::default(),
176             disable_experimental: Default::default(),
177             disabled: Default::default(),
178             expr_fill_default: Default::default(),
179             insert_use: InsertUseConfig {
180                 granularity: ImportGranularity::Preserve,
181                 enforce_granularity: false,
182                 prefix_kind: PrefixKind::Plain,
183                 group: false,
184                 skip_glob_imports: false,
185             },
186             prefer_no_std: false,
187         }
188     }
189 }
190 
191 struct DiagnosticsContext<'a> {
192     config: &'a DiagnosticsConfig,
193     sema: Semantics<'a, RootDatabase>,
194     resolve: &'a AssistResolveStrategy,
195 }
196 
197 impl<'a> DiagnosticsContext<'a> {
resolve_precise_location( &self, node: &InFile<SyntaxNodePtr>, precise_location: Option<TextRange>, ) -> TextRange198     fn resolve_precise_location(
199         &self,
200         node: &InFile<SyntaxNodePtr>,
201         precise_location: Option<TextRange>,
202     ) -> TextRange {
203         let sema = &self.sema;
204         (|| {
205             let precise_location = precise_location?;
206             let root = sema.parse_or_expand(node.file_id);
207             match root.covering_element(precise_location) {
208                 syntax::NodeOrToken::Node(it) => Some(sema.original_range(&it)),
209                 syntax::NodeOrToken::Token(it) => {
210                     node.with_value(it).original_file_range_opt(sema.db)
211                 }
212             }
213         })()
214         .unwrap_or_else(|| sema.diagnostics_display_range(node.clone()))
215         .range
216     }
217 }
218 
diagnostics( db: &RootDatabase, config: &DiagnosticsConfig, resolve: &AssistResolveStrategy, file_id: FileId, ) -> Vec<Diagnostic>219 pub fn diagnostics(
220     db: &RootDatabase,
221     config: &DiagnosticsConfig,
222     resolve: &AssistResolveStrategy,
223     file_id: FileId,
224 ) -> Vec<Diagnostic> {
225     let _p = profile::span("diagnostics");
226     let sema = Semantics::new(db);
227     let parse = db.parse(file_id);
228     let mut res = Vec::new();
229 
230     // [#34344] Only take first 128 errors to prevent slowing down editor/ide, the number 128 is chosen arbitrarily.
231     res.extend(
232         parse.errors().iter().take(128).map(|err| {
233             Diagnostic::new("syntax-error", format!("Syntax Error: {err}"), err.range())
234         }),
235     );
236 
237     let parse = sema.parse(file_id);
238 
239     for node in parse.syntax().descendants() {
240         handlers::useless_braces::useless_braces(&mut res, file_id, &node);
241         handlers::field_shorthand::field_shorthand(&mut res, file_id, &node);
242         handlers::json_is_not_rust::json_in_items(&sema, &mut res, file_id, &node, config);
243     }
244 
245     let module = sema.to_module_def(file_id);
246 
247     let ctx = DiagnosticsContext { config, sema, resolve };
248     if module.is_none() {
249         handlers::unlinked_file::unlinked_file(&ctx, &mut res, file_id);
250     }
251 
252     let mut diags = Vec::new();
253     if let Some(m) = module {
254         m.diagnostics(db, &mut diags);
255     }
256 
257     for diag in diags {
258         #[rustfmt::skip]
259         let d = match diag {
260             AnyDiagnostic::ExpectedFunction(d) => handlers::expected_function::expected_function(&ctx, &d),
261             AnyDiagnostic::InactiveCode(d) => match handlers::inactive_code::inactive_code(&ctx, &d) {
262                 Some(it) => it,
263                 None => continue,
264             }
265             AnyDiagnostic::IncoherentImpl(d) => handlers::incoherent_impl::incoherent_impl(&ctx, &d),
266             AnyDiagnostic::IncorrectCase(d) => handlers::incorrect_case::incorrect_case(&ctx, &d),
267             AnyDiagnostic::InvalidDeriveTarget(d) => handlers::invalid_derive_target::invalid_derive_target(&ctx, &d),
268             AnyDiagnostic::MacroDefError(d) => handlers::macro_error::macro_def_error(&ctx, &d),
269             AnyDiagnostic::MacroError(d) => handlers::macro_error::macro_error(&ctx, &d),
270             AnyDiagnostic::MacroExpansionParseError(d) => {
271                 res.extend(d.errors.iter().take(32).map(|err| {
272                     {
273                         Diagnostic::new(
274                             "syntax-error",
275                             format!("Syntax Error in Expansion: {err}"),
276                             ctx.resolve_precise_location(&d.node.clone(), d.precise_location),
277                         )
278                     }
279                     .experimental()
280                 }));
281                 continue;
282             },
283             AnyDiagnostic::MalformedDerive(d) => handlers::malformed_derive::malformed_derive(&ctx, &d),
284             AnyDiagnostic::MismatchedArgCount(d) => handlers::mismatched_arg_count::mismatched_arg_count(&ctx, &d),
285             AnyDiagnostic::MissingFields(d) => handlers::missing_fields::missing_fields(&ctx, &d),
286             AnyDiagnostic::MissingMatchArms(d) => handlers::missing_match_arms::missing_match_arms(&ctx, &d),
287             AnyDiagnostic::MissingUnsafe(d) => handlers::missing_unsafe::missing_unsafe(&ctx, &d),
288             AnyDiagnostic::MovedOutOfRef(d) => handlers::moved_out_of_ref::moved_out_of_ref(&ctx, &d),
289             AnyDiagnostic::NeedMut(d) => handlers::mutability_errors::need_mut(&ctx, &d),
290             AnyDiagnostic::NoSuchField(d) => handlers::no_such_field::no_such_field(&ctx, &d),
291             AnyDiagnostic::PrivateAssocItem(d) => handlers::private_assoc_item::private_assoc_item(&ctx, &d),
292             AnyDiagnostic::PrivateField(d) => handlers::private_field::private_field(&ctx, &d),
293             AnyDiagnostic::ReplaceFilterMapNextWithFindMap(d) => handlers::replace_filter_map_next_with_find_map::replace_filter_map_next_with_find_map(&ctx, &d),
294             AnyDiagnostic::TypedHole(d) => handlers::typed_hole::typed_hole(&ctx, &d),
295             AnyDiagnostic::TypeMismatch(d) => handlers::type_mismatch::type_mismatch(&ctx, &d),
296             AnyDiagnostic::UndeclaredLabel(d) => handlers::undeclared_label::undeclared_label(&ctx, &d),
297             AnyDiagnostic::UnimplementedBuiltinMacro(d) => handlers::unimplemented_builtin_macro::unimplemented_builtin_macro(&ctx, &d),
298             AnyDiagnostic::UnreachableLabel(d) => handlers::unreachable_label:: unreachable_label(&ctx, &d),
299             AnyDiagnostic::UnresolvedExternCrate(d) => handlers::unresolved_extern_crate::unresolved_extern_crate(&ctx, &d),
300             AnyDiagnostic::UnresolvedField(d) => handlers::unresolved_field::unresolved_field(&ctx, &d),
301             AnyDiagnostic::UnresolvedImport(d) => handlers::unresolved_import::unresolved_import(&ctx, &d),
302             AnyDiagnostic::UnresolvedMacroCall(d) => handlers::unresolved_macro_call::unresolved_macro_call(&ctx, &d),
303             AnyDiagnostic::UnresolvedMethodCall(d) => handlers::unresolved_method::unresolved_method(&ctx, &d),
304             AnyDiagnostic::UnresolvedModule(d) => handlers::unresolved_module::unresolved_module(&ctx, &d),
305             AnyDiagnostic::UnresolvedProcMacro(d) => handlers::unresolved_proc_macro::unresolved_proc_macro(&ctx, &d, config.proc_macros_enabled, config.proc_attr_macros_enabled),
306             AnyDiagnostic::UnusedMut(d) => handlers::mutability_errors::unused_mut(&ctx, &d),
307             AnyDiagnostic::BreakOutsideOfLoop(d) => handlers::break_outside_of_loop::break_outside_of_loop(&ctx, &d),
308         };
309         res.push(d)
310     }
311 
312     res.retain(|d| {
313         !ctx.config.disabled.contains(d.code.as_str())
314             && !(ctx.config.disable_experimental && d.experimental)
315     });
316 
317     res
318 }
319 
fix(id: &'static str, label: &str, source_change: SourceChange, target: TextRange) -> Assist320 fn fix(id: &'static str, label: &str, source_change: SourceChange, target: TextRange) -> Assist {
321     let mut res = unresolved_fix(id, label, target);
322     res.source_change = Some(source_change);
323     res
324 }
325 
unresolved_fix(id: &'static str, label: &str, target: TextRange) -> Assist326 fn unresolved_fix(id: &'static str, label: &str, target: TextRange) -> Assist {
327     assert!(!id.contains(' '));
328     Assist {
329         id: AssistId(id, AssistKind::QuickFix),
330         label: Label::new(label.to_string()),
331         group: None,
332         target,
333         source_change: None,
334         trigger_signature_help: false,
335     }
336 }
337 
adjusted_display_range<N: AstNode>( ctx: &DiagnosticsContext<'_>, diag_ptr: InFile<SyntaxNodePtr>, adj: &dyn Fn(N) -> Option<TextRange>, ) -> TextRange338 fn adjusted_display_range<N: AstNode>(
339     ctx: &DiagnosticsContext<'_>,
340     diag_ptr: InFile<SyntaxNodePtr>,
341     adj: &dyn Fn(N) -> Option<TextRange>,
342 ) -> TextRange {
343     let FileRange { file_id, range } = ctx.sema.diagnostics_display_range(diag_ptr);
344 
345     let source_file = ctx.sema.db.parse(file_id);
346     find_node_at_range::<N>(&source_file.syntax_node(), range)
347         .filter(|it| it.syntax().text_range() == range)
348         .and_then(adj)
349         .unwrap_or(range)
350 }
351