Show dead code with reduced opacity (FuelLabs#3800)

Closes FuelLabs#3747 I realized that I missed a couple declaration types in FuelLabs#3769, so I updated those to use the name spans as well. - const declarations - variable declarations Before: <img width="494" alt="image" src="https://user-images.githubusercontent.com/47993817/213106817-0b093ec0-599e-4200-901d-bc64a0388a26.png"> After: <img width="569" alt="image" src="https://user-images.githubusercontent.com/47993817/213063161-842bdc27-2bdb-40e7-aad0-93c7413af318.png">
mehtavishwa30 · Jan 18, 2023 · 0c99c8a · 0c99c8a
1 parent a97c97f
commit 0c99c8a
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Showing 4 changed files with 114 additions and 22 deletions.
diff --git a/sway-core/src/control_flow_analysis/dead_code_analysis.rs b/sway-core/src/control_flow_analysis/dead_code_analysis.rs
@@ -1683,6 +1683,39 @@ fn construct_dead_code_warning_from_node(
                 warning_content: Warning::DeadTrait,
             }
         }
+        ty::TyAstNode {
+            content:
+                ty::TyAstNodeContent::Declaration(ty::TyDeclaration::ConstantDeclaration(decl_id)),
+            span,
+        } => {
+            let warning_span = match decl_engine.get_constant(decl_id.clone(), span) {
+                Ok(ty::TyConstantDeclaration { name, .. }) => name.span(),
+                Err(_) => span.clone(),
+            };
+            CompileWarning {
+                span: warning_span,
+                warning_content: Warning::DeadDeclaration,
+            }
+        }
+        ty::TyAstNode {
+            content: ty::TyAstNodeContent::Declaration(ty::TyDeclaration::VariableDeclaration(decl)),
+            span,
+        } => {
+            // In rare cases, variable declaration spans don't have a path, so we need to check for that
+            if decl.name.span().path().is_some() {
+                CompileWarning {
+                    span: decl.name.span(),
+                    warning_content: Warning::DeadDeclaration,
+                }
+            } else if span.path().is_some() {
+                CompileWarning {
+                    span: span.clone(),
+                    warning_content: Warning::DeadDeclaration,
+                }
+            } else {
+                return None;
+            }
+        }
         ty::TyAstNode {
             content: ty::TyAstNodeContent::Declaration(ty::TyDeclaration::ImplTrait(decl_id)),
             span,

diff --git a/sway-lsp/src/capabilities/diagnostic.rs b/sway-lsp/src/capabilities/diagnostic.rs
@@ -1,7 +1,7 @@
-use tower_lsp::lsp_types::{Diagnostic, DiagnosticSeverity, Position, Range};
+use tower_lsp::lsp_types::{Diagnostic, DiagnosticSeverity, DiagnosticTag, Position, Range};
 
-use sway_error::error::CompileError;
 use sway_error::warning::CompileWarning;
+use sway_error::{error::CompileError, warning::Warning};
 use sway_types::{LineCol, Spanned};
 
 #[derive(Debug)]
@@ -24,6 +24,7 @@ fn get_warning_diagnostics(warnings: &[CompileWarning]) -> Vec<Diagnostic> {
         range: get_range(warning.span().line_col()),
         severity: Some(DiagnosticSeverity::WARNING),
         message: warning.to_friendly_warning_string(),
+        tags: get_warning_diagnostic_tags(&warning.warning_content),
         ..Default::default()
     }))
 }
@@ -41,3 +42,22 @@ fn get_range((start, end): (LineCol, LineCol)) -> Range {
     let end = pos(end);
     Range { start, end }
 }
+
+fn get_warning_diagnostic_tags(warning: &Warning) -> Option<Vec<DiagnosticTag>> {
+    match warning {
+        Warning::StructFieldNeverRead
+        | Warning::DeadDeclaration
+        | Warning::DeadEnumDeclaration
+        | Warning::DeadEnumVariant { .. }
+        | Warning::DeadFunctionDeclaration
+        | Warning::DeadMethod
+        | Warning::DeadStorageDeclaration
+        | Warning::DeadStorageDeclarationForFunction { .. }
+        | Warning::DeadStructDeclaration
+        | Warning::DeadTrait
+        | Warning::MatchExpressionUnreachableArm
+        | Warning::UnreachableCode
+        | Warning::UnusedReturnValue { .. } => Some(vec![DiagnosticTag::UNNECESSARY]),
+        _ => None,
+    }
+}
diff --git a/sway-lsp/test/fixtures/diagnostics/dead_code/expected.json b/sway-lsp/test/fixtures/diagnostics/dead_code/expected.json
@@ -15,7 +15,10 @@
             "line": 31
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "Enum variant A is never constructed.",
@@ -29,7 +32,10 @@
             "line": 25
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "Enum variant B is never constructed.",
@@ -43,35 +49,44 @@
             "line": 26
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This declaration is never used.",
         "range": {
           "end": {
-            "character": 24,
+            "character": 18,
             "line": 13
           },
           "start": {
-            "character": 0,
+            "character": 6,
             "line": 13
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This declaration is never used.",
         "range": {
           "end": {
-            "character": 38,
+            "character": 24,
             "line": 14
           },
           "start": {
-            "character": 0,
+            "character": 6,
             "line": 14
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This struct is never used.",
@@ -85,7 +100,10 @@
             "line": 15
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This struct field is never accessed.",
@@ -99,7 +117,10 @@
             "line": 16
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This struct field is never accessed.",
@@ -113,7 +134,10 @@
             "line": 17
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This trait is never implemented.",
@@ -127,7 +151,10 @@
             "line": 20
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This enum is never used.",
@@ -141,7 +168,10 @@
             "line": 24
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This function is never called.",
@@ -155,21 +185,27 @@
             "line": 34
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This declaration is never used.",
         "range": {
           "end": {
-            "character": 23,
+            "character": 18,
             "line": 35
           },
           "start": {
-            "character": 4,
+            "character": 8,
             "line": 35
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       },
       {
         "message": "This function is never called.",
@@ -183,7 +219,10 @@
             "line": 42
           }
         },
-        "severity": 2
+        "severity": 2,
+        "tags": [
+          1
+        ]
       }
     ]
   }

diff --git a/sway-types/src/span.rs b/sway-types/src/span.rs
@@ -211,7 +211,7 @@ pub trait Spanned {
     fn span(&self) -> Span;
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 pub struct LineCol {
     pub line: usize,
     pub col: usize,