Implementation of diagnostic reporting style for dfa engine

compiler/include/dmd/globals.h

@@ -35,7 +35,8 @@ enum class MessageStyle : unsigned char
 {
     digitalmars, // file(line,column): message
     gnu,         // file:line:column: message
-    sarif        // JSON SARIF output, see https://docs.oasis-open.org/sarif/sarif/v2.1.0/sarif-v2.1.0.html
+    sarif,       // JSON SARIF output, see https://docs.oasis-open.org/sarif/sarif/v2.1.0/sarif-v2.1.0.html
+    diagreport   // diagnostics reporting messagestyle
 };
 
 // The state of array bounds checking

compiler/src/build.d

@@ -1571,7 +1571,7 @@ auto sourceFiles()
             glue/s2ir.d glue/tocsym.d glue/toctype.d glue/tocvdebug.d glue/todt.d glue/toir.d glue/toobj.d
         "),
         driver: fileArray(env["D"], "dinifile.d dmdparams.d lib/package.d lib/elf.d lib/mach.d lib/mscoff.d
-            link.d mars.d main.d sarif.d lib/scanelf.d lib/scanmach.d lib/scanmscoff.d timetrace.d vsoptions.d
+            link.d mars.d main.d sarif.d diagreport/glue.d lib/scanelf.d lib/scanmach.d lib/scanmscoff.d timetrace.d vsoptions.d
         "),
         frontend: fileArray(env["D"], "
             access.d aggregate.d aliasthis.d argtypes_x86.d argtypes_sysv_x64.d argtypes_aarch64.d arrayop.d
@@ -1592,6 +1592,7 @@ auto sourceFiles()
             visitor/strict.d visitor/transitive.d
             cparse.d
             dfa/entry.d dfa/utils.d dfa/fast/structure.d dfa/fast/analysis.d dfa/fast/report.d dfa/fast/expression.d dfa/fast/statement.d
+            diagreport/defs.d diagreport/geometry.d diagreport/renderer.d
         "),
         backendHeaders: fileArray(env["C"], "
             cc.d cdef.d cgcv.d code.d dt.d el.d global.d

compiler/src/dmd/cli.d

@@ -935,14 +935,15 @@ dmd -cov -unittest myprog.d
         Option("vcolumns",
             "print character (column) numbers in diagnostics"
         ),
-        Option("verror-style=[digitalmars|gnu|sarif]",
+        Option("verror-style=[digitalmars|gnu|sarif|diagreport]",
             "set the style for file/line number annotations on compiler messages",
             `Set the style for file/line number annotations on compiler messages,
             where:
             $(DL
             $(DT digitalmars)$(DD 'file(line[,column]): message'. This is the default.)
             $(DT gnu)$(DD 'file:line[:column]: message', conforming to the GNU standard used by gcc and clang.)
             $(DT sarif)$(DD 'Generates JSON output conforming to the SARIF (Static Analysis Results Interchange Format) standard, useful for integration with tools like GitHub and other SARIF readers.')
+            $(DT diagreport)$(DD 'Generates diagnostic report of errors, warnings, deprecations and tips.')
             )`,
         ),
         Option("verror-supplements=<num>",

compiler/src/dmd/diagreport/defs.d

@@ -0,0 +1,59 @@
+/**
+    Defines the vertical state of a diagnostic on a given line for drawing purposes.
+    This enumeration captures the vertical state machine logic for a single diagnostic span.
+*/
+module dmd.diagreport.defs;
+
+enum LineClassification
+{
+    /// The line is not part of the diagnostic span.
+    Inactive,
+    /// The line is the start of the span and continues below. Implies the previous line was Inactive.
+    SpanStart,
+    /// The line is between the start and end. Implies the previous line and next line are Active.
+    SpanContinue,
+    /// The line is the end of the span and no other active diagnostics follow it. Implies the next line is Inactive.
+    SpanEnd,
+    /// The span starts and ends on the same line (a one-line diagnostic).
+    SpanStartEnd
+}
+
+struct Diagnostic
+{
+    /// The line number where the diagnostic span begins (inclusive).
+    int start;
+    /// The line number where the diagnostic span ends (inclusive).
+    int end;
+
+    Message startMessage;
+    Message endMessage;
+
+    size_t id;
+
+    size_t offset()
+    {
+        return originalOffset;
+    }
+
+package:
+    size_t originalOffset;
+    int column;
+}
+
+struct Message
+{
+    int startColumn, endColumn;
+    bool isMultiline;
+
+    size_t id;
+}
+
+struct Help
+{
+    Diagnostic[] diagnostics;
+
+    Message startMessage;
+    Message endMessage;
+
+    size_t id;
+}