2 files changed, 139 insertions, 1 deletions

diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs
index 24fff690a..bd370e3b2 100644
--- a/crates/hir_ty/src/diagnostics.rs
+++ b/crates/hir_ty/src/diagnostics.rs
@@ -257,7 +257,7 @@ impl fmt::Display for CaseType {
         let repr = match self {
             CaseType::LowerSnakeCase => "snake_case",
             CaseType::UpperSnakeCase => "UPPER_SNAKE_CASE",
-            CaseType::UpperCamelCase => "UpperCamelCase",
+            CaseType::UpperCamelCase => "CamelCase",
         };
 
         write!(f, "{}", repr)
diff --git a/crates/hir_ty/src/diagnostics/decl_check.rs b/crates/hir_ty/src/diagnostics/decl_check.rs
index 1a0906492..b7f511fd8 100644
--- a/crates/hir_ty/src/diagnostics/decl_check.rs
+++ b/crates/hir_ty/src/diagnostics/decl_check.rs
@@ -14,6 +14,7 @@ mod str_helpers;
 use std::sync::Arc;
 
 use hir_def::{
+    adt::VariantData,
     body::Body,
     db::DefDatabase,
     expr::{Expr, ExprId, UnaryOp},
@@ -205,6 +206,133 @@ impl<'a, 'b> DeclValidator<'a, 'b> {
 
     fn validate_struct(&mut self, db: &dyn HirDatabase, struct_id: StructId) {
         let data = db.struct_data(struct_id);
+
+        // 1. Check the structure name.
+        let struct_name = data.name.to_string();
+        let struct_name_replacement = if let Some(new_name) = to_camel_case(&struct_name) {
+            let replacement = Replacement {
+                current_name: data.name.clone(),
+                suggested_text: new_name,
+                expected_case: CaseType::UpperCamelCase,
+            };
+            Some(replacement)
+        } else {
+            None
+        };
+
+        // 2. Check the field names.
+        let mut struct_fields_replacements = Vec::new();
+
+        if let VariantData::Record(fields) = data.variant_data.as_ref() {
+            for (_, field) in fields.iter() {
+                let field_name = field.name.to_string();
+                if let Some(new_name) = to_lower_snake_case(&field_name) {
+                    let replacement = Replacement {
+                        current_name: field.name.clone(),
+                        suggested_text: new_name,
+                        expected_case: CaseType::LowerSnakeCase,
+                    };
+                    struct_fields_replacements.push(replacement);
+                }
+            }
+        }
+
+        // 3. If there is at least one element to spawn a warning on, go to the source map and generate a warning.
+        self.create_incorrect_case_diagnostic_for_struct(
+            struct_id,
+            db,
+            struct_name_replacement,
+            struct_fields_replacements,
+        )
+    }
+
+    /// Given the information about incorrect names in the struct declaration, looks up into the source code
+    /// for exact locations and adds diagnostics into the sink.
+    fn create_incorrect_case_diagnostic_for_struct(
+        &mut self,
+        struct_id: StructId,
+        db: &dyn HirDatabase,
+        struct_name_replacement: Option<Replacement>,
+        struct_fields_replacements: Vec<Replacement>,
+    ) {
+        // XXX: only look at sources if we do have incorrect names
+        if struct_name_replacement.is_none() && struct_fields_replacements.is_empty() {
+            return;
+        }
+
+        let struct_loc = struct_id.lookup(db.upcast());
+        let struct_src = struct_loc.source(db.upcast());
+
+        if let Some(replacement) = struct_name_replacement {
+            let ast_ptr = if let Some(name) = struct_src.value.name() {
+                name
+            } else {
+                // We don't want rust-analyzer to panic over this, but it is definitely some kind of error in the logic.
+                log::error!(
+                    "Replacement ({:?}) was generated for a structure without a name: {:?}",
+                    replacement,
+                    struct_src
+                );
+                return;
+            };
+
+            let diagnostic = IncorrectCase {
+                file: struct_src.file_id,
+                ident_type: "Structure".to_string(),
+                ident: AstPtr::new(&ast_ptr).into(),
+                expected_case: replacement.expected_case,
+                ident_text: replacement.current_name.to_string(),
+                suggested_text: replacement.suggested_text,
+            };
+
+            self.sink.push(diagnostic);
+        }
+
+        // let fn_params_list = match fn_src.value.param_list() {
+        //     Some(params) => params,
+        //     None => {
+        //         if !fn_param_replacements.is_empty() {
+        //             log::error!(
+        //                 "Replacements ({:?}) were generated for a function parameters which had no parameters list: {:?}",
+        //                 fn_param_replacements, fn_src
+        //             );
+        //         }
+        //         return;
+        //     }
+        // };
+        // let mut fn_params_iter = fn_params_list.params();
+        // for param_to_rename in fn_param_replacements {
+        //     // We assume that parameters in replacement are in the same order as in the
+        //     // actual params list, but just some of them (ones that named correctly) are skipped.
+        //     let ast_ptr = loop {
+        //         match fn_params_iter.next() {
+        //             Some(element)
+        //                 if pat_equals_to_name(element.pat(), &param_to_rename.current_name) =>
+        //             {
+        //                 break element.pat().unwrap()
+        //             }
+        //             Some(_) => {}
+        //             None => {
+        //                 log::error!(
+        //                     "Replacement ({:?}) was generated for a function parameter which was not found: {:?}",
+        //                     param_to_rename, fn_src
+        //                 );
+        //                 return;
+        //             }
+        //         }
+        //     };
+
+        //     let diagnostic = IncorrectCase {
+        //         file: fn_src.file_id,
+        //         ident_type: "Argument".to_string(),
+        //         ident: AstPtr::new(&ast_ptr).into(),
+        //         expected_case: param_to_rename.expected_case,
+        //         ident_text: param_to_rename.current_name.to_string(),
+        //         suggested_text: param_to_rename.suggested_text,
+        //     };
+
+        //     self.sink.push(diagnostic);
+        // }
     }
 
     fn validate_enum(&mut self, db: &dyn HirDatabase, enum_id: EnumId) {
@@ -246,4 +374,14 @@ fn foo2(ok_param: &str, CAPS_PARAM: u8) {}
 "#,
         );
     }
+
+    #[test]
+    fn incorrect_struct_name() {
+        check_diagnostics(
+            r#"
+struct non_camel_case_name {}
+    // ^^^^^^^^^^^^^^^^^^^ Structure `non_camel_case_name` should have a CamelCase name, e.g. `NonCamelCaseName`
+"#,
+        );
+    }
 }