feat(diagnostics): print source diagnostics in gcc file:line: layout

Lexer, parser, driver and codegen diagnostics now read
"<path>:<line>: error: <message>" instead of "error: <message> at line N
in <path>". The path is always printed as given on the command line.
Call sites pass the bare message to cps::sourceError/sourceWarning, which
carry printf format checking; reportError routes through the same helper.

The suite iii harness parses the new layout and matches the reason
against the message only. iii/template-class-pack-field passed only
because its reason regex matched the case path, so it is now
case-insensitive.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/lib/CodeGen/FunctionGen.cc b/lib/CodeGen/FunctionGen.cc
index c01b042..628f3ba 100644
--- a/lib/CodeGen/FunctionGen.cc
+++ b/lib/CodeGen/FunctionGen.cc
@@ -30,10 +30,7 @@ bool FunctionGen::isReservedRuntimeName(const std::string &Name) {
 void FunctionGen::reportError(const char *Fmt, ...) {
     va_list Args;
     va_start(Args, Fmt);
-    fprintf(stderr, "error: ");
-    vfprintf(stderr, Fmt, Args);
-    if (DiagnosticLine) fprintf(stderr, "%s", lineSuffix(DiagnosticLine).c_str());
-    fprintf(stderr, "\n");
+    cps::vsourceDiagnostic(cps::Severity::Error, DiagnosticLine, Fmt, Args);
     va_end(Args);
     HadError = true;
 }
@@ -449,7 +446,7 @@ static Value *GenerateCall(llvm::Module &Module,
                            bool &HadError, int DiagnosticLine) {
     Function *CalleeF = Module.getFunction(CalleeName);
     if (!CalleeF) {
-        sourceDiagnostic(DiagnosticLine, "error: Call to undefined function %s\n", CalleeName.c_str());
+        sourceError(DiagnosticLine, "Call to undefined function %s", CalleeName.c_str());
         HadError = true;
         return nullptr;
     }