support picking up full dead module diagnostics. mark dead code diagn…

…ostics as unused code. simplify/inline a few things

client/src/commands/dead_code_analysis.ts

@@ -11,6 +11,7 @@ import {
   CodeAction,
   CodeActionKind,
   WorkspaceEdit,
+  DiagnosticTag,
 } from "vscode";
 
 export type DiagnosticsResultCodeActionsMap = Map<
@@ -103,39 +104,41 @@ let dceTextToDiagnostics = (
     let processedFileInfo = extractFileInfo(fileInfo);
 
     if (processedFileInfo != null) {
-      // reanalyze prints the severity first in the title, and then the rest of
-      // the title after.
-      let [severityRaw, ...issueTitleParts] = title.split(" ");
-      let issueTitle = issueTitleParts.join(" ");
-
       let [startCharacter, endCharacter] =
         processedFileInfo.characters.split("-");
 
       let startPos = new Position(
         // reanalyze reports lines as index 1 based, while VSCode wants them
-        // index 0 based.
-        parseInt(processedFileInfo.line, 10) - 1,
-        parseInt(startCharacter, 10)
+        // index 0 based. reanalyze reports diagnostics for an entire file on
+        // line 0 (and chars 0-0). So, we need to ensure that we don't give
+        // VSCode a negative line index, or it'll be sad.
+        Math.max(0, parseInt(processedFileInfo.line, 10) - 1),
+        Math.max(0, parseInt(startCharacter, 10))
       );
 
       let endPos = new Position(
-        parseInt(processedFileInfo.line, 10) - 1,
-        parseInt(endCharacter, 10)
+        Math.max(0, parseInt(processedFileInfo.line, 10) - 1),
+        Math.max(0, parseInt(endCharacter, 10))
       );
 
-      let issueLocationRange = new Range(startPos, endPos);
+      // Detect if this is a dead module diagnostic. If so, highlight the
+      // entire file.
+      if (title === "Warning Dead Module") {
+        startPos = new Position(0, 0);
+        endPos = new Position(99999, 0);
+      }
 
-      let severity =
-        severityRaw === "Error"
-          ? DiagnosticSeverity.Error
-          : DiagnosticSeverity.Warning;
+      let issueLocationRange = new Range(startPos, endPos);
 
       let diagnostic = new Diagnostic(
         issueLocationRange,
-        `${issueTitle}: ${text}`,
-        severity
+        text.trim(),
+        DiagnosticSeverity.Warning
       );
 
+      // This will render the part of the code as unused
+      diagnostic.tags = [DiagnosticTag.Unnecessary];
+
       if (diagnosticsMap.has(processedFileInfo.filePath)) {
         diagnosticsMap.get(processedFileInfo.filePath).push(diagnostic);
       } else {
@@ -151,7 +154,7 @@ let dceTextToDiagnostics = (
         let actualLineToReplaceStr = lineNumToReplace.split("<-- line ").pop();
 
         if (actualLineToReplaceStr != null) {
-          let codeAction = new CodeAction(`Annotate with @dead`);
+          let codeAction = new CodeAction(`Suppress dead code warning`);
           codeAction.kind = CodeActionKind.RefactorRewrite;
 
           let codeActionEdit = new WorkspaceEdit();