selfhost: C backend becomes primary backend; QBE path removed from CLI

Major changes:
- Cli_BuildProject now uses CBackend_Generate instead of QBE SSA generation
- Replaced QBE invocation (vendor/qbe/qbe) with direct cc compilation
- Cli_Build (single-file) now compiles C output with cc including runtime.c/io.c
- Added import-based stdlib merging: only imported Std::* modules are merged,
  eliminating unused generic code from Array/Map/Set/Channel in simple programs

C backend fixes:
- Fixed struct typedef redefinition: struct definitions now use 'struct Name {}'
  instead of 'typedef struct {} Name' to avoid conflicting with forward typedefs
- Added enum support: HirEnum struct, enum emission in C backend, variant
  constants emitted as #define Name_Value
- Added char8 typedef
- Skip generic structs/functions (T/K/V type parameters) in C emission

Sema fixes:
- Fixed Sema_IsNumeric: now correctly recognizes uint, float32, float64
- Fixed return type check: allow pointer compatibility (String <-> *T)

Tested: hello, fibonacci, factorial, enums examples build and run via buxc2

_selfhost/src/c_backend.bux

@@ -440,6 +440,47 @@ func CBE_EmitFuncDecl(cbe: *CEmitter, f: *HirFunc) {
     StringBuilder_Append(&cbe.sb, ")");
 }
 
+// ---------------------------------------------------------------------------
+// Helpers for detecting generic declarations (not yet monomorphized)
+// ---------------------------------------------------------------------------
+
+func CBE_IsGenericTypeName(name: String) -> bool {
+    if String_Eq(name, "T") || String_Eq(name, "K") || String_Eq(name, "V") { return true; }
+    if String_Eq(name, "T*") || String_Eq(name, "K*") || String_Eq(name, "V*") { return true; }
+    // Generic container structs and their pointer variants
+    if String_Eq(name, "Array") || String_Eq(name, "Array*") { return true; }
+    if String_Eq(name, "SetEntry") || String_Eq(name, "SetEntry*") { return true; }
+    if String_Eq(name, "StringMapEntry") || String_Eq(name, "StringMapEntry*") { return true; }
+    if String_Eq(name, "MapEntry") || String_Eq(name, "MapEntry*") { return true; }
+    return false;
+}
+
+func CBE_StructHasGeneric(st: *HirStruct) -> bool {
+    var fi: int = 0;
+    while fi < st.fieldCount {
+        if CBE_IsGenericTypeName(st.fields[fi].typeName) { return true; }
+        fi = fi + 1;
+    }
+    return false;
+}
+
+func CBE_FuncHasGeneric(f: *HirFunc) -> bool {
+    var pi: int = 0;
+    while pi < f.paramCount {
+        var ptype: String = "";
+        if pi == 0 { ptype = f.param0.typeName; }
+        if pi == 1 { ptype = f.param1.typeName; }
+        if pi == 2 { ptype = f.param2.typeName; }
+        if pi == 3 { ptype = f.param3.typeName; }
+        if pi == 4 { ptype = f.param4.typeName; }
+        if pi == 5 { ptype = f.param5.typeName; }
+        if CBE_IsGenericTypeName(ptype) { return true; }
+        pi = pi + 1;
+    }
+    if CBE_IsGenericTypeName(f.retTypeName) { return true; }
+    return false;
+}
+
 // ---------------------------------------------------------------------------
 // Generate complete C module
 // ---------------------------------------------------------------------------
@@ -466,27 +507,62 @@ func CBackend_Generate(mod: *HirModule) -> String {
     StringBuilder_Append(&cbe.sb, "typedef short int16;\n");
     StringBuilder_Append(&cbe.sb, "typedef long long int64;\n");
     StringBuilder_Append(&cbe.sb, "typedef float float32;\n");
-    StringBuilder_Append(&cbe.sb, "typedef double float64;\n\n");
+    StringBuilder_Append(&cbe.sb, "typedef double float64;\n");
+    StringBuilder_Append(&cbe.sb, "typedef char char8;\n\n");
     // Runtime declarations
     StringBuilder_Append(&cbe.sb, "void* bux_alloc(unsigned int size);\n");
     StringBuilder_Append(&cbe.sb, "void bux_free(void* ptr);\n\n");
 
-    // Forward declare all struct types
+    // Forward declare all struct types (skip generics)
     var si: int = 0;
     while si < mod.structCount {
-        StringBuilder_Append(&cbe.sb, "typedef struct ");
+        if !CBE_StructHasGeneric(&mod.structs[si]) {
-        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+            StringBuilder_Append(&cbe.sb, "typedef struct ");
-        StringBuilder_Append(&cbe.sb, " ");
+            StringBuilder_Append(&cbe.sb, mod.structs[si].name);
-        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+            StringBuilder_Append(&cbe.sb, " ");
-        StringBuilder_Append(&cbe.sb, ";\n");
+            StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+            StringBuilder_Append(&cbe.sb, ";\n");
+        }
         si = si + 1;
     }
     StringBuilder_Append(&cbe.sb, "\n");
 
-    // Struct definitions
+    // Enum definitions (typedef to int)
+    var ei: int = 0;
+    while ei < mod.enumCount {
+        StringBuilder_Append(&cbe.sb, "typedef int ");
+        StringBuilder_Append(&cbe.sb, mod.enums[ei].name);
+        StringBuilder_Append(&cbe.sb, ";\n");
+        ei = ei + 1;
+    }
+    if mod.enumCount > 0 {
+        StringBuilder_Append(&cbe.sb, "\n");
+    }
+
+    // Constant definitions
+    var ci: int = 0;
+    while ci < mod.constCount {
+        StringBuilder_Append(&cbe.sb, "#define ");
+        StringBuilder_Append(&cbe.sb, mod.consts[ci].name);
+        StringBuilder_Append(&cbe.sb, " ");
+        StringBuilder_Append(&cbe.sb, String_FromInt(mod.consts[ci].value as int64));
+        StringBuilder_Append(&cbe.sb, "\n");
+        ci = ci + 1;
+    }
+    if mod.constCount > 0 {
+        StringBuilder_Append(&cbe.sb, "\n");
+    }
+
+    // Struct definitions (skip generics)
     si = 0;
     while si < mod.structCount {
-        StringBuilder_Append(&cbe.sb, "typedef struct {\n");
+        if CBE_StructHasGeneric(&mod.structs[si]) {
+            si = si + 1;
+            continue;
+        }
+        StringBuilder_Append(&cbe.sb, "struct ");
+        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+        StringBuilder_Append(&cbe.sb, " {\n");
         var fi: int = 0;
         while fi < mod.structs[si].fieldCount {
             StringBuilder_Append(&cbe.sb, "    ");
@@ -508,17 +584,17 @@ func CBackend_Generate(mod: *HirModule) -> String {
             StringBuilder_Append(&cbe.sb, ";\n");
             fi = fi + 1;
         }
-        StringBuilder_Append(&cbe.sb, "} ");
+        StringBuilder_Append(&cbe.sb, "};\n\n");
-        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
-        StringBuilder_Append(&cbe.sb, ";\n\n");
         si = si + 1;
     }
 
-    // Forward declarations for all functions
+    // Forward declarations for all functions (skip generics)
     var i: int = 0;
     while i < mod.funcCount {
-        CBE_EmitFuncDecl(cbe, &mod.funcs[i]);
+        if !CBE_FuncHasGeneric(&mod.funcs[i]) {
-        StringBuilder_Append(&cbe.sb, ";\n");
+            CBE_EmitFuncDecl(cbe, &mod.funcs[i]);
+            StringBuilder_Append(&cbe.sb, ";\n");
+        }
         i = i + 1;
     }
     StringBuilder_Append(&cbe.sb, "\n");
@@ -532,11 +608,16 @@ func CBackend_Generate(mod: *HirModule) -> String {
     }
     StringBuilder_Append(&cbe.sb, "\n");
 
-    // Function definitions
+    // Function definitions (skip generics)
     var hasMain: bool = false;
     i = 0;
     while i < mod.funcCount {
         if String_Eq(mod.funcs[i].name, "Main") { hasMain = true; }
+        // Skip generic functions
+        if CBE_FuncHasGeneric(&mod.funcs[i]) {
+            i = i + 1;
+            continue;
+        }
         // Skip forward declarations (functions without body)
         let body: *HirNode = mod.funcs[i].body;
         if body == null as *HirNode {

_selfhost/src/cli.bux

@@ -1,5 +1,5 @@
 // cli.bux — CLI driver for the Bux self-hosting compiler
-// Wires together: Lexer → Parser → Sema → HirLower → NimBackend
+// Wires together: Lexer → Parser → Sema → HirLower → CBackend
 module Cli {
 
 extern func PrintLine(s: String);
@@ -97,14 +97,14 @@ func Cli_Compile(source: String, sourceName: String) -> String {
     Print("HIR funcCount=");
     PrintInt(hirMod.funcCount);
 
-    // Phase 5: QBE SSA code generation
+    // Phase 5: C code generation
-    let qbeCode: String = QbeBackend_Generate(hirMod);
+    let cCode: String = CBackend_Generate(hirMod);
 
     // Cleanup
     Lexer_Free(lex);
     Sema_Free(sema);
 
-    return qbeCode;
+    return cCode;
 }
 
 // ---------------------------------------------------------------------------
@@ -122,23 +122,64 @@ func Cli_Build(srcPath: String, outPath: String) -> int {
     Print("Compiling ");
     PrintLine(srcPath);
 
-    let ssaCode: String = Cli_Compile(source, srcPath);
+    let cCode: String = Cli_Compile(source, srcPath);
 
-    if String_Eq(ssaCode, "") {
+    if String_Eq(cCode, "") {
         PrintLine("Compilation failed");
         return 1;
     }
 
-    // Write SSA output
+    // Write C output
-    let ok: bool = WriteFile(outPath, ssaCode);
+    let cFile: String = String_Concat(outPath, ".c");
-    if ok {
+    let ok: bool = WriteFile(cFile, cCode);
-        Print("  → SSA written to ");
+    if !ok {
-        PrintLine(outPath);
-        return 0;
-    } else {
         PrintLine("Error: cannot write output file");
         return 1;
     }
+    Print("  → C written to ");
+    PrintLine(cFile);
+
+    // Find runtime.c and io.c for linking
+    var rtPath: String = "stdlib/runtime.c";
+    var ioPath: String = "stdlib/io.c";
+    if !FileExists(rtPath) {
+        rtPath = "../stdlib/runtime.c";
+    }
+    if !FileExists(ioPath) {
+        ioPath = "../stdlib/io.c";
+    }
+    if !FileExists(rtPath) {
+        rtPath = "/home/ziko/z-git/bux/bux/stdlib/runtime.c";
+    }
+    if !FileExists(ioPath) {
+        ioPath = "/home/ziko/z-git/bux/bux/stdlib/io.c";
+    }
+
+    // Compile with cc
+    PrintLine("Compiling C...");
+    var cmdBuf: StringBuilder = StringBuilder_NewCap(512);
+    StringBuilder_Append(&cmdBuf, "cc -O2 -pthread -o ");
+    StringBuilder_Append(&cmdBuf, outPath);
+    StringBuilder_Append(&cmdBuf, " ");
+    StringBuilder_Append(&cmdBuf, cFile);
+    StringBuilder_Append(&cmdBuf, " ");
+    if FileExists(rtPath) {
+        StringBuilder_Append(&cmdBuf, rtPath);
+        StringBuilder_Append(&cmdBuf, " ");
+    }
+    if FileExists(ioPath) {
+        StringBuilder_Append(&cmdBuf, ioPath);
+        StringBuilder_Append(&cmdBuf, " ");
+    }
+    StringBuilder_Append(&cmdBuf, "-lm");
+    let ccRc: int = bux_system(StringBuilder_Build(&cmdBuf));
+    if ccRc != 0 {
+        PrintLine("Error: C compilation failed");
+        return 1;
+    }
+    Print("  → Binary: ");
+    PrintLine(outPath);
+    return 0;
 }
 
 // ---------------------------------------------------------------------------
@@ -307,6 +348,55 @@ func Cli_CollectNames(mod: *Module, names: *String, maxCount: int) -> int {
     return count;
 }
 
+// Helper: convert single char int to String
+func String_FromChar(c: int) -> String {
+    var buf: *char8 = bux_alloc(2) as *char8;
+    buf[0] = c as char8;
+    buf[1] = 0 as char8;
+    return buf as String;
+}
+
+// Collect stdlib module paths imported by user code.
+// Returns number of unique stdlib files to merge (paths written into outPaths).
+func Cli_CollectStdlibImports(mod: *Module, outPaths: *String, maxCount: int, stdlibDir: String) -> int {
+    if mod == null as *Module { return 0; }
+    var count: int = 0;
+    var decl: *Decl = mod.firstItem;
+    while decl != null as *Decl && count < maxCount {
+        if decl.kind == dkUse {
+            let path: String = decl.usePath;
+            // Only handle Std::* imports
+            if String_StartsWith(path, "Std::") {
+                // Extract module name after Std:: (e.g., "Std::Io" -> "Io")
+                var j: int = 5; // skip "Std::"
+                var modName: String = "";
+                while j < 100 {
+                    let c: int = path[j] as int;
+                    if c == 0 || c == 58 { break; } // null or ':'
+                    modName = String_Concat(modName, String_FromChar(c));
+                    j = j + 1;
+                }
+                if !String_Eq(modName, "") {
+                    let filePath: String = bux_path_join(bux_path_join(stdlibDir, "Std"), String_Concat(modName, ".bux"));
+                    // Check for duplicates
+                    var dup: bool = false;
+                    var di: int = 0;
+                    while di < count {
+                        if String_Eq(outPaths[di], filePath) { dup = true; }
+                        di = di + 1;
+                    }
+                    if !dup {
+                        outPaths[count] = filePath;
+                        count = count + 1;
+                    }
+                }
+            }
+        }
+        decl = decl.childDecl2;
+    }
+    return count;
+}
+
 func Cli_MergeFileInto(target: *Module, path: String, skipNames: *String, skipCount: int) -> int {
     Print("DEBUG: MergeFileInto ");
     PrintLine(path);
@@ -473,39 +563,30 @@ func Cli_BuildProject(projectDir: String) -> int {
     merged.itemCount = 0;
     merged.firstItem = null as *Decl;
 
-    // Find and merge stdlib declarations
+    // Find and merge stdlib declarations (only imported modules)
     let stdlibDir: String = Cli_FindStdlibDir(projectDir);
     if !String_Eq(stdlibDir, "") {
         Print("Stdlib found: ");
         PrintLine(stdlibDir);
-        let stdSubdir: String = bux_path_join(stdlibDir, "Std");
+        // Collect imported stdlib modules from user code
-        if DirExists(stdSubdir) {
+        let maxImports: int = 64;
-            var stdFileCount: int = 0;
+        let importPaths: *String = bux_alloc(maxImports * 8) as *String;
-            let stdFiles: *String = bux_list_dir(stdSubdir, ".bux", &stdFileCount);
+        let importCount: int = Cli_CollectStdlibImports(userMerged, importPaths, maxImports, stdlibDir);
-            Print("DEBUG: stdFileCount=");
+        Print("Imported stdlib modules: ");
-            PrintInt(stdFileCount);
+        PrintInt(importCount);
-            if stdFileCount > 0 {
+        PrintLine("");
-                Print("Merging ");
+        if importCount > 0 {
-                PrintInt(stdFileCount);
+            var si: int = 0;
-                PrintLine(" stdlib files");
+            var stdAdded: int = 0;
-                var si: int = 0;
+            while si < importCount {
-                var stdAdded: int = 0;
+                Print("  Merging ");
-                while si < stdFileCount {
+                PrintLine(importPaths[si]);
-                    Print("DEBUG: merging stdlib file ");
+                let added: int = Cli_MergeFileInto(merged, importPaths[si], userNames, userNameCount);
-                    PrintInt(si);
+                stdAdded = stdAdded + added;
-                    // Skip Channel.bux for debugging
+                si = si + 1;
-                    if String_Eq(stdFiles[si], "./../stdlib/Std/Channel.bux") {
-                        PrintLine("DEBUG: skipping Channel.bux");
-                        si = si + 1;
-                        continue;
-                    }
-                    let added: int = Cli_MergeFileInto(merged, stdFiles[si], userNames, userNameCount);
-                    stdAdded = stdAdded + added;
-                    si = si + 1;
-                }
-                Print("Stdlib declarations added: ");
-                PrintInt(stdAdded);
             }
+            Print("Stdlib declarations added: ");
+            PrintInt(stdAdded);
         }
     }
 
@@ -554,6 +635,14 @@ func Cli_BuildProject(projectDir: String) -> int {
     let sema: *Sema = Sema_Analyze(merged);
     if Sema_HasError(sema) {
         PrintLine("Sema errors found");
+        var i: int = 0;
+        while i < Sema_DiagCount(sema) {
+            Print("  line ");
+            PrintInt(sema.diags[i].line as int64);
+            Print(": ");
+            PrintLine(sema.diags[i].message);
+            i = i + 1;
+        }
         return 1;
     }
 
@@ -569,85 +658,60 @@ func Cli_BuildProject(projectDir: String) -> int {
     }
     let hirMod: *HirModule = HirLower_LowerModule(merged, sema);
 
-    // QBE SSA code generation
+    // C code generation
-    PrintLine("Generating QBE SSA...");
+    PrintLine("Generating C code...");
-    var fi: int = 0;
+    let cCode: String = CBackend_Generate(hirMod);
-    while fi < hirMod.funcCount {
-        Print("func ");
-        PrintLine(hirMod.funcs[fi].name);
-        fi = fi + 1;
-    }
-    let qbeCode: String = QbeBackend_Generate(hirMod);
 
     // Create build directory
     let buildDir: String = bux_path_join(projectDir, "build");
     discard bux_mkdir_if_needed(buildDir);
 
-    // Write SSA output
+    // Write C output
-    let ssaFile: String = bux_path_join(buildDir, "main.ssa");
+    let cFile: String = bux_path_join(buildDir, "main.c");
-    if !WriteFile(ssaFile, qbeCode) {
+    if !WriteFile(cFile, cCode) {
-        PrintLine("Error: cannot write main.ssa");
+        PrintLine("Error: cannot write main.c");
         return 1;
     }
+    Print("C code written to ");
+    PrintLine(cFile);
 
-    Print("SSA written to ");
+    // Find runtime.c and io.c (use stdlibDir if available)
-    PrintLine(ssaFile);
+    var rtPath: String = bux_path_join(stdlibDir, "runtime.c");
-
+    var ioPath: String = bux_path_join(stdlibDir, "io.c");
-    // Invoke QBE to generate assembly
+    if !FileExists(rtPath) {
-    PrintLine("Invoking QBE...");
+        rtPath = bux_path_join(projectDir, "stdlib/runtime.c");
-    let asmFile: String = bux_path_join(buildDir, "main.s");
-    var qbeCmd: String = bux_path_join(projectDir, "vendor/qbe/qbe");
-    // Try relative to project first, then absolute
-    if !FileExists(qbeCmd) {
-        // Try from compiler location
-        qbeCmd = "../vendor/qbe/qbe";
     }
-    if !FileExists(qbeCmd) {
+    if !FileExists(ioPath) {
-        qbeCmd = "vendor/qbe/qbe";
+        ioPath = bux_path_join(projectDir, "stdlib/io.c");
     }
-    // Actually let's use bux_system with a constructed command
-    var cmdBuf: StringBuilder = StringBuilder_NewCap(256);
-    StringBuilder_Append(&cmdBuf, qbeCmd);
-    StringBuilder_Append(&cmdBuf, " -o ");
-    StringBuilder_Append(&cmdBuf, asmFile);
-    StringBuilder_Append(&cmdBuf, " ");
-    StringBuilder_Append(&cmdBuf, ssaFile);
-    let qbeRc: int = bux_system(StringBuilder_Build(&cmdBuf));
-    if qbeRc != 0 {
-        PrintLine("Error: QBE compilation failed");
-        return 1;
-    }
-
-    // Link with cc
-    PrintLine("Linking...");
-    var linkBuf: StringBuilder = StringBuilder_NewCap(512);
-    StringBuilder_Append(&linkBuf, "cc -o ");
-    let outBin: String = bux_path_join(buildDir, outName);
-    StringBuilder_Append(&linkBuf, outBin);
-    StringBuilder_Append(&linkBuf, " ");
-    StringBuilder_Append(&linkBuf, asmFile);
-    StringBuilder_Append(&linkBuf, " ");
-    // Find runtime.c and io.c
-    var rtPath: String = bux_path_join(projectDir, "stdlib/runtime.c");
-    var ioPath: String = bux_path_join(projectDir, "stdlib/io.c");
     if !FileExists(rtPath) {
         rtPath = bux_path_join(projectDir, "../stdlib/runtime.c");
     }
     if !FileExists(ioPath) {
         ioPath = bux_path_join(projectDir, "../stdlib/io.c");
     }
+
+    // Compile with cc
+    PrintLine("Compiling C...");
+    let outBin: String = bux_path_join(buildDir, outName);
+    var ccBuf: StringBuilder = StringBuilder_NewCap(512);
+    StringBuilder_Append(&ccBuf, "cc -O2 -pthread -o ");
+    StringBuilder_Append(&ccBuf, outBin);
+    StringBuilder_Append(&ccBuf, " ");
+    StringBuilder_Append(&ccBuf, cFile);
+    StringBuilder_Append(&ccBuf, " ");
     if FileExists(rtPath) {
-        StringBuilder_Append(&linkBuf, rtPath);
+        StringBuilder_Append(&ccBuf, rtPath);
-        StringBuilder_Append(&linkBuf, " ");
+        StringBuilder_Append(&ccBuf, " ");
     }
     if FileExists(ioPath) {
-        StringBuilder_Append(&linkBuf, ioPath);
+        StringBuilder_Append(&ccBuf, ioPath);
-        StringBuilder_Append(&linkBuf, " ");
+        StringBuilder_Append(&ccBuf, " ");
     }
-    StringBuilder_Append(&linkBuf, "-lm");
+    StringBuilder_Append(&ccBuf, "-lm");
-    let linkRc: int = bux_system(StringBuilder_Build(&linkBuf));
+    let ccRc: int = bux_system(StringBuilder_Build(&ccBuf));
-    if linkRc != 0 {
+    if ccRc != 0 {
-        PrintLine("Error: Linking failed");
+        PrintLine("Error: C compilation failed");
         return 1;
     }
 
@@ -693,7 +757,7 @@ func Cli_Run(args: *String, argCount: int) -> int {
         PrintLine("  Parser     ✅ 1004 lines");
         PrintLine("  Sema       ✅  393 lines");
         PrintLine("  HirLower   ✅  307 lines");
-        PrintLine("  CBackend   ✅  264 lines");
+        PrintLine("  CBackend   ✅  585 lines");
         PrintLine("  Total: 3830 lines of Bux");
         return 0;
     }
@@ -716,7 +780,7 @@ func Cli_Run(args: *String, argCount: int) -> int {
 
     if String_Eq(cmd, "build") {
         let src: String = "src/Main.bux";
-        let out: String = "build/main.nim";
+        let out: String = "build/main";
         if argCount >= 3 { src = args[2]; }
         if argCount >= 4 { out = args[3]; }
         return Cli_Build(src, out);

_selfhost/src/hir.bux

@@ -115,6 +115,10 @@ struct HirConst {
     value: int;
 }
 
+struct HirEnum {
+    name: String;
+}
+
 struct HirModule {
     funcCount: int;
     funcs: *HirFunc;
@@ -123,6 +127,7 @@ struct HirModule {
     structCount: int;
     structs: *HirStruct;
     enumCount: int;
+    enums: *HirEnum;
     constCount: int;
     consts: *HirConst;
 }

_selfhost/src/hir_lower.bux

@@ -213,6 +213,16 @@ func Lcx_LowerExpr(ctx: *LowerCtx, expr: *Expr) -> *HirNode {
 
     // Field access
     if kind == ekField {
+        // Check if this is enum variant access: Color::Green
+        if expr.child1 != null as *Expr && expr.child1.kind == ekIdent {
+            let sym: Symbol = Scope_Lookup(ctx.scope, expr.child1.strValue);
+            if sym.decl != null as *Decl && sym.decl.kind == dkEnum {
+                // Emit as variable reference: Color_Green
+                n.kind = hVar;
+                n.strValue = String_Concat(String_Concat(expr.child1.strValue, "_"), expr.strValue);
+                return n;
+            }
+        }
         n.kind = hFieldPtr;
         n.child1 = Lcx_LowerExpr(ctx, expr.child1);
         n.strValue = expr.strValue;
@@ -543,6 +553,8 @@ func HirLower_LowerModule(mod: *Module, sema: *Sema) -> *HirModule {
     hm.funcs = ctx.funcs;
     hm.structCount = 0;
     hm.structs = bux_alloc(64 as uint * sizeof(HirStruct)) as *HirStruct;
+    hm.enumCount = 0;
+    hm.enums = bux_alloc(64 as uint * sizeof(HirEnum)) as *HirEnum;
     hm.constCount = 0;
     hm.consts = bux_alloc(512 as uint * sizeof(HirConst)) as *HirConst;
 
@@ -628,7 +640,25 @@ func HirLower_LowerModule(mod: *Module, sema: *Sema) -> *HirModule {
             hm.constCount = hm.constCount + 1;
         }
         if decl.kind == dkEnum {
+            let ei: int = hm.enumCount;
+            hm.enums[ei].name = decl.strValue;
             hm.enumCount = hm.enumCount + 1;
+            // Emit enum variants as constants: EnumName_VariantName = value
+            var vi: int = 0;
+            while vi < decl.variantCount && hm.constCount < 512 {
+                var vname: String = "";
+                if vi == 0 { vname = decl.variant0.name; }
+                if vi == 1 { vname = decl.variant1.name; }
+                if vi == 2 { vname = decl.variant2.name; }
+                if vi == 3 { vname = decl.variant3.name; }
+                if !String_Eq(vname, "") {
+                    let ci: int = hm.constCount;
+                    hm.consts[ci].name = String_Concat(String_Concat(decl.strValue, "_"), vname);
+                    hm.consts[ci].value = vi;
+                    hm.constCount = hm.constCount + 1;
+                }
+                vi = vi + 1;
+            }
         }
         decl = decl.childDecl2;
     }

_selfhost/src/sema.bux

@@ -96,7 +96,10 @@ func Sema_ResolveType(sema: *Sema, te: *TypeExpr) -> int {
 
 func Sema_IsNumeric(kind: int) -> bool {
     if kind == tyUnknown || kind == tyNamed || kind == tyTypeParam { return true; }
-    return kind >= tyInt8 && kind <= tyUInt64;
+    if kind == tyInt8 || kind == tyInt16 || kind == tyInt32 || kind == tyInt64 || kind == tyInt { return true; }
+    if kind == tyUInt8 || kind == tyUInt16 || kind == tyUInt32 || kind == tyUInt64 || kind == tyUInt { return true; }
+    if kind == tyFloat32 || kind == tyFloat64 { return true; }
+    return false;
 }
 
 func Sema_IsBool(kind: int) -> bool {
@@ -328,9 +331,12 @@ func Sema_CheckStmt(sema: *Sema, stmt: *Stmt) {
             let retType: int = Sema_CheckExpr(sema, stmt.child1);
             if sema.currentRetType != tyUnknown && retType != tyUnknown {
                 if retType != sema.currentRetType {
-                    // Be permissive: allow numeric widening, pointer/named mismatch
+                    // Be permissive: allow numeric widening, pointer compatibility
                     if !Sema_IsNumeric(retType) || !Sema_IsNumeric(sema.currentRetType) {
-                        if retType != sema.currentRetType {
+                        // Allow pointer-type compatibility (String <-> *T, *T <-> *U)
+                        let retIsPtr: bool = retType == tyPointer || retType == tyStr;
+                        let expectedIsPtr: bool = sema.currentRetType == tyPointer || sema.currentRetType == tyStr;
+                        if !retIsPtr || !expectedIsPtr {
                             Sema_EmitError(sema, stmt.line, stmt.column, "return type mismatch");
                         }
                     }

src_bux/c_backend.bux

@@ -440,6 +440,47 @@ func CBE_EmitFuncDecl(cbe: *CEmitter, f: *HirFunc) {
     StringBuilder_Append(&cbe.sb, ")");
 }
 
+// ---------------------------------------------------------------------------
+// Helpers for detecting generic declarations (not yet monomorphized)
+// ---------------------------------------------------------------------------
+
+func CBE_IsGenericTypeName(name: String) -> bool {
+    if String_Eq(name, "T") || String_Eq(name, "K") || String_Eq(name, "V") { return true; }
+    if String_Eq(name, "T*") || String_Eq(name, "K*") || String_Eq(name, "V*") { return true; }
+    // Generic container structs and their pointer variants
+    if String_Eq(name, "Array") || String_Eq(name, "Array*") { return true; }
+    if String_Eq(name, "SetEntry") || String_Eq(name, "SetEntry*") { return true; }
+    if String_Eq(name, "StringMapEntry") || String_Eq(name, "StringMapEntry*") { return true; }
+    if String_Eq(name, "MapEntry") || String_Eq(name, "MapEntry*") { return true; }
+    return false;
+}
+
+func CBE_StructHasGeneric(st: *HirStruct) -> bool {
+    var fi: int = 0;
+    while fi < st.fieldCount {
+        if CBE_IsGenericTypeName(st.fields[fi].typeName) { return true; }
+        fi = fi + 1;
+    }
+    return false;
+}
+
+func CBE_FuncHasGeneric(f: *HirFunc) -> bool {
+    var pi: int = 0;
+    while pi < f.paramCount {
+        var ptype: String = "";
+        if pi == 0 { ptype = f.param0.typeName; }
+        if pi == 1 { ptype = f.param1.typeName; }
+        if pi == 2 { ptype = f.param2.typeName; }
+        if pi == 3 { ptype = f.param3.typeName; }
+        if pi == 4 { ptype = f.param4.typeName; }
+        if pi == 5 { ptype = f.param5.typeName; }
+        if CBE_IsGenericTypeName(ptype) { return true; }
+        pi = pi + 1;
+    }
+    if CBE_IsGenericTypeName(f.retTypeName) { return true; }
+    return false;
+}
+
 // ---------------------------------------------------------------------------
 // Generate complete C module
 // ---------------------------------------------------------------------------
@@ -466,27 +507,62 @@ func CBackend_Generate(mod: *HirModule) -> String {
     StringBuilder_Append(&cbe.sb, "typedef short int16;\n");
     StringBuilder_Append(&cbe.sb, "typedef long long int64;\n");
     StringBuilder_Append(&cbe.sb, "typedef float float32;\n");
-    StringBuilder_Append(&cbe.sb, "typedef double float64;\n\n");
+    StringBuilder_Append(&cbe.sb, "typedef double float64;\n");
+    StringBuilder_Append(&cbe.sb, "typedef char char8;\n\n");
     // Runtime declarations
     StringBuilder_Append(&cbe.sb, "void* bux_alloc(unsigned int size);\n");
     StringBuilder_Append(&cbe.sb, "void bux_free(void* ptr);\n\n");
 
-    // Forward declare all struct types
+    // Forward declare all struct types (skip generics)
     var si: int = 0;
     while si < mod.structCount {
-        StringBuilder_Append(&cbe.sb, "typedef struct ");
+        if !CBE_StructHasGeneric(&mod.structs[si]) {
-        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+            StringBuilder_Append(&cbe.sb, "typedef struct ");
-        StringBuilder_Append(&cbe.sb, " ");
+            StringBuilder_Append(&cbe.sb, mod.structs[si].name);
-        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+            StringBuilder_Append(&cbe.sb, " ");
-        StringBuilder_Append(&cbe.sb, ";\n");
+            StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+            StringBuilder_Append(&cbe.sb, ";\n");
+        }
         si = si + 1;
     }
     StringBuilder_Append(&cbe.sb, "\n");
 
-    // Struct definitions
+    // Enum definitions (typedef to int)
+    var ei: int = 0;
+    while ei < mod.enumCount {
+        StringBuilder_Append(&cbe.sb, "typedef int ");
+        StringBuilder_Append(&cbe.sb, mod.enums[ei].name);
+        StringBuilder_Append(&cbe.sb, ";\n");
+        ei = ei + 1;
+    }
+    if mod.enumCount > 0 {
+        StringBuilder_Append(&cbe.sb, "\n");
+    }
+
+    // Constant definitions
+    var ci: int = 0;
+    while ci < mod.constCount {
+        StringBuilder_Append(&cbe.sb, "#define ");
+        StringBuilder_Append(&cbe.sb, mod.consts[ci].name);
+        StringBuilder_Append(&cbe.sb, " ");
+        StringBuilder_Append(&cbe.sb, String_FromInt(mod.consts[ci].value as int64));
+        StringBuilder_Append(&cbe.sb, "\n");
+        ci = ci + 1;
+    }
+    if mod.constCount > 0 {
+        StringBuilder_Append(&cbe.sb, "\n");
+    }
+
+    // Struct definitions (skip generics)
     si = 0;
     while si < mod.structCount {
-        StringBuilder_Append(&cbe.sb, "typedef struct {\n");
+        if CBE_StructHasGeneric(&mod.structs[si]) {
+            si = si + 1;
+            continue;
+        }
+        StringBuilder_Append(&cbe.sb, "struct ");
+        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
+        StringBuilder_Append(&cbe.sb, " {\n");
         var fi: int = 0;
         while fi < mod.structs[si].fieldCount {
             StringBuilder_Append(&cbe.sb, "    ");
@@ -508,17 +584,17 @@ func CBackend_Generate(mod: *HirModule) -> String {
             StringBuilder_Append(&cbe.sb, ";\n");
             fi = fi + 1;
         }
-        StringBuilder_Append(&cbe.sb, "} ");
+        StringBuilder_Append(&cbe.sb, "};\n\n");
-        StringBuilder_Append(&cbe.sb, mod.structs[si].name);
-        StringBuilder_Append(&cbe.sb, ";\n\n");
         si = si + 1;
     }
 
-    // Forward declarations for all functions
+    // Forward declarations for all functions (skip generics)
     var i: int = 0;
     while i < mod.funcCount {
-        CBE_EmitFuncDecl(cbe, &mod.funcs[i]);
+        if !CBE_FuncHasGeneric(&mod.funcs[i]) {
-        StringBuilder_Append(&cbe.sb, ";\n");
+            CBE_EmitFuncDecl(cbe, &mod.funcs[i]);
+            StringBuilder_Append(&cbe.sb, ";\n");
+        }
         i = i + 1;
     }
     StringBuilder_Append(&cbe.sb, "\n");
@@ -532,11 +608,16 @@ func CBackend_Generate(mod: *HirModule) -> String {
     }
     StringBuilder_Append(&cbe.sb, "\n");
 
-    // Function definitions
+    // Function definitions (skip generics)
     var hasMain: bool = false;
     i = 0;
     while i < mod.funcCount {
         if String_Eq(mod.funcs[i].name, "Main") { hasMain = true; }
+        // Skip generic functions
+        if CBE_FuncHasGeneric(&mod.funcs[i]) {
+            i = i + 1;
+            continue;
+        }
         // Skip forward declarations (functions without body)
         let body: *HirNode = mod.funcs[i].body;
         if body == null as *HirNode {

src_bux/cli.bux

@@ -1,5 +1,5 @@
 // cli.bux — CLI driver for the Bux self-hosting compiler
-// Wires together: Lexer → Parser → Sema → HirLower → NimBackend
+// Wires together: Lexer → Parser → Sema → HirLower → CBackend
 module Cli {
 
 extern func PrintLine(s: String);
@@ -97,14 +97,14 @@ func Cli_Compile(source: String, sourceName: String) -> String {
     Print("HIR funcCount=");
     PrintInt(hirMod.funcCount);
 
-    // Phase 5: QBE SSA code generation
+    // Phase 5: C code generation
-    let qbeCode: String = QbeBackend_Generate(hirMod);
+    let cCode: String = CBackend_Generate(hirMod);
 
     // Cleanup
     Lexer_Free(lex);
     Sema_Free(sema);
 
-    return qbeCode;
+    return cCode;
 }
 
 // ---------------------------------------------------------------------------
@@ -122,23 +122,64 @@ func Cli_Build(srcPath: String, outPath: String) -> int {
     Print("Compiling ");
     PrintLine(srcPath);
 
-    let ssaCode: String = Cli_Compile(source, srcPath);
+    let cCode: String = Cli_Compile(source, srcPath);
 
-    if String_Eq(ssaCode, "") {
+    if String_Eq(cCode, "") {
         PrintLine("Compilation failed");
         return 1;
     }
 
-    // Write SSA output
+    // Write C output
-    let ok: bool = WriteFile(outPath, ssaCode);
+    let cFile: String = String_Concat(outPath, ".c");
-    if ok {
+    let ok: bool = WriteFile(cFile, cCode);
-        Print("  → SSA written to ");
+    if !ok {
-        PrintLine(outPath);
-        return 0;
-    } else {
         PrintLine("Error: cannot write output file");
         return 1;
     }
+    Print("  → C written to ");
+    PrintLine(cFile);
+
+    // Find runtime.c and io.c for linking
+    var rtPath: String = "stdlib/runtime.c";
+    var ioPath: String = "stdlib/io.c";
+    if !FileExists(rtPath) {
+        rtPath = "../stdlib/runtime.c";
+    }
+    if !FileExists(ioPath) {
+        ioPath = "../stdlib/io.c";
+    }
+    if !FileExists(rtPath) {
+        rtPath = "/home/ziko/z-git/bux/bux/stdlib/runtime.c";
+    }
+    if !FileExists(ioPath) {
+        ioPath = "/home/ziko/z-git/bux/bux/stdlib/io.c";
+    }
+
+    // Compile with cc
+    PrintLine("Compiling C...");
+    var cmdBuf: StringBuilder = StringBuilder_NewCap(512);
+    StringBuilder_Append(&cmdBuf, "cc -O2 -pthread -o ");
+    StringBuilder_Append(&cmdBuf, outPath);
+    StringBuilder_Append(&cmdBuf, " ");
+    StringBuilder_Append(&cmdBuf, cFile);
+    StringBuilder_Append(&cmdBuf, " ");
+    if FileExists(rtPath) {
+        StringBuilder_Append(&cmdBuf, rtPath);
+        StringBuilder_Append(&cmdBuf, " ");
+    }
+    if FileExists(ioPath) {
+        StringBuilder_Append(&cmdBuf, ioPath);
+        StringBuilder_Append(&cmdBuf, " ");
+    }
+    StringBuilder_Append(&cmdBuf, "-lm");
+    let ccRc: int = bux_system(StringBuilder_Build(&cmdBuf));
+    if ccRc != 0 {
+        PrintLine("Error: C compilation failed");
+        return 1;
+    }
+    Print("  → Binary: ");
+    PrintLine(outPath);
+    return 0;
 }
 
 // ---------------------------------------------------------------------------
@@ -307,6 +348,55 @@ func Cli_CollectNames(mod: *Module, names: *String, maxCount: int) -> int {
     return count;
 }
 
+// Helper: convert single char int to String
+func String_FromChar(c: int) -> String {
+    var buf: *char8 = bux_alloc(2) as *char8;
+    buf[0] = c as char8;
+    buf[1] = 0 as char8;
+    return buf as String;
+}
+
+// Collect stdlib module paths imported by user code.
+// Returns number of unique stdlib files to merge (paths written into outPaths).
+func Cli_CollectStdlibImports(mod: *Module, outPaths: *String, maxCount: int, stdlibDir: String) -> int {
+    if mod == null as *Module { return 0; }
+    var count: int = 0;
+    var decl: *Decl = mod.firstItem;
+    while decl != null as *Decl && count < maxCount {
+        if decl.kind == dkUse {
+            let path: String = decl.usePath;
+            // Only handle Std::* imports
+            if String_StartsWith(path, "Std::") {
+                // Extract module name after Std:: (e.g., "Std::Io" -> "Io")
+                var j: int = 5; // skip "Std::"
+                var modName: String = "";
+                while j < 100 {
+                    let c: int = path[j] as int;
+                    if c == 0 || c == 58 { break; } // null or ':'
+                    modName = String_Concat(modName, String_FromChar(c));
+                    j = j + 1;
+                }
+                if !String_Eq(modName, "") {
+                    let filePath: String = bux_path_join(bux_path_join(stdlibDir, "Std"), String_Concat(modName, ".bux"));
+                    // Check for duplicates
+                    var dup: bool = false;
+                    var di: int = 0;
+                    while di < count {
+                        if String_Eq(outPaths[di], filePath) { dup = true; }
+                        di = di + 1;
+                    }
+                    if !dup {
+                        outPaths[count] = filePath;
+                        count = count + 1;
+                    }
+                }
+            }
+        }
+        decl = decl.childDecl2;
+    }
+    return count;
+}
+
 func Cli_MergeFileInto(target: *Module, path: String, skipNames: *String, skipCount: int) -> int {
     Print("DEBUG: MergeFileInto ");
     PrintLine(path);
@@ -473,39 +563,30 @@ func Cli_BuildProject(projectDir: String) -> int {
     merged.itemCount = 0;
     merged.firstItem = null as *Decl;
 
-    // Find and merge stdlib declarations
+    // Find and merge stdlib declarations (only imported modules)
     let stdlibDir: String = Cli_FindStdlibDir(projectDir);
     if !String_Eq(stdlibDir, "") {
         Print("Stdlib found: ");
         PrintLine(stdlibDir);
-        let stdSubdir: String = bux_path_join(stdlibDir, "Std");
+        // Collect imported stdlib modules from user code
-        if DirExists(stdSubdir) {
+        let maxImports: int = 64;
-            var stdFileCount: int = 0;
+        let importPaths: *String = bux_alloc(maxImports * 8) as *String;
-            let stdFiles: *String = bux_list_dir(stdSubdir, ".bux", &stdFileCount);
+        let importCount: int = Cli_CollectStdlibImports(userMerged, importPaths, maxImports, stdlibDir);
-            Print("DEBUG: stdFileCount=");
+        Print("Imported stdlib modules: ");
-            PrintInt(stdFileCount);
+        PrintInt(importCount);
-            if stdFileCount > 0 {
+        PrintLine("");
-                Print("Merging ");
+        if importCount > 0 {
-                PrintInt(stdFileCount);
+            var si: int = 0;
-                PrintLine(" stdlib files");
+            var stdAdded: int = 0;
-                var si: int = 0;
+            while si < importCount {
-                var stdAdded: int = 0;
+                Print("  Merging ");
-                while si < stdFileCount {
+                PrintLine(importPaths[si]);
-                    Print("DEBUG: merging stdlib file ");
+                let added: int = Cli_MergeFileInto(merged, importPaths[si], userNames, userNameCount);
-                    PrintInt(si);
+                stdAdded = stdAdded + added;
-                    // Skip Channel.bux for debugging
+                si = si + 1;
-                    if String_Eq(stdFiles[si], "./../stdlib/Std/Channel.bux") {
-                        PrintLine("DEBUG: skipping Channel.bux");
-                        si = si + 1;
-                        continue;
-                    }
-                    let added: int = Cli_MergeFileInto(merged, stdFiles[si], userNames, userNameCount);
-                    stdAdded = stdAdded + added;
-                    si = si + 1;
-                }
-                Print("Stdlib declarations added: ");
-                PrintInt(stdAdded);
             }
+            Print("Stdlib declarations added: ");
+            PrintInt(stdAdded);
         }
     }
 
@@ -554,6 +635,14 @@ func Cli_BuildProject(projectDir: String) -> int {
     let sema: *Sema = Sema_Analyze(merged);
     if Sema_HasError(sema) {
         PrintLine("Sema errors found");
+        var i: int = 0;
+        while i < Sema_DiagCount(sema) {
+            Print("  line ");
+            PrintInt(sema.diags[i].line as int64);
+            Print(": ");
+            PrintLine(sema.diags[i].message);
+            i = i + 1;
+        }
         return 1;
     }
 
@@ -569,85 +658,60 @@ func Cli_BuildProject(projectDir: String) -> int {
     }
     let hirMod: *HirModule = HirLower_LowerModule(merged, sema);
 
-    // QBE SSA code generation
+    // C code generation
-    PrintLine("Generating QBE SSA...");
+    PrintLine("Generating C code...");
-    var fi: int = 0;
+    let cCode: String = CBackend_Generate(hirMod);
-    while fi < hirMod.funcCount {
-        Print("func ");
-        PrintLine(hirMod.funcs[fi].name);
-        fi = fi + 1;
-    }
-    let qbeCode: String = QbeBackend_Generate(hirMod);
 
     // Create build directory
     let buildDir: String = bux_path_join(projectDir, "build");
     discard bux_mkdir_if_needed(buildDir);
 
-    // Write SSA output
+    // Write C output
-    let ssaFile: String = bux_path_join(buildDir, "main.ssa");
+    let cFile: String = bux_path_join(buildDir, "main.c");
-    if !WriteFile(ssaFile, qbeCode) {
+    if !WriteFile(cFile, cCode) {
-        PrintLine("Error: cannot write main.ssa");
+        PrintLine("Error: cannot write main.c");
         return 1;
     }
+    Print("C code written to ");
+    PrintLine(cFile);
 
-    Print("SSA written to ");
+    // Find runtime.c and io.c (use stdlibDir if available)
-    PrintLine(ssaFile);
+    var rtPath: String = bux_path_join(stdlibDir, "runtime.c");
-
+    var ioPath: String = bux_path_join(stdlibDir, "io.c");
-    // Invoke QBE to generate assembly
+    if !FileExists(rtPath) {
-    PrintLine("Invoking QBE...");
+        rtPath = bux_path_join(projectDir, "stdlib/runtime.c");
-    let asmFile: String = bux_path_join(buildDir, "main.s");
-    var qbeCmd: String = bux_path_join(projectDir, "vendor/qbe/qbe");
-    // Try relative to project first, then absolute
-    if !FileExists(qbeCmd) {
-        // Try from compiler location
-        qbeCmd = "../vendor/qbe/qbe";
     }
-    if !FileExists(qbeCmd) {
+    if !FileExists(ioPath) {
-        qbeCmd = "vendor/qbe/qbe";
+        ioPath = bux_path_join(projectDir, "stdlib/io.c");
     }
-    // Actually let's use bux_system with a constructed command
-    var cmdBuf: StringBuilder = StringBuilder_NewCap(256);
-    StringBuilder_Append(&cmdBuf, qbeCmd);
-    StringBuilder_Append(&cmdBuf, " -o ");
-    StringBuilder_Append(&cmdBuf, asmFile);
-    StringBuilder_Append(&cmdBuf, " ");
-    StringBuilder_Append(&cmdBuf, ssaFile);
-    let qbeRc: int = bux_system(StringBuilder_Build(&cmdBuf));
-    if qbeRc != 0 {
-        PrintLine("Error: QBE compilation failed");
-        return 1;
-    }
-
-    // Link with cc
-    PrintLine("Linking...");
-    var linkBuf: StringBuilder = StringBuilder_NewCap(512);
-    StringBuilder_Append(&linkBuf, "cc -o ");
-    let outBin: String = bux_path_join(buildDir, outName);
-    StringBuilder_Append(&linkBuf, outBin);
-    StringBuilder_Append(&linkBuf, " ");
-    StringBuilder_Append(&linkBuf, asmFile);
-    StringBuilder_Append(&linkBuf, " ");
-    // Find runtime.c and io.c
-    var rtPath: String = bux_path_join(projectDir, "stdlib/runtime.c");
-    var ioPath: String = bux_path_join(projectDir, "stdlib/io.c");
     if !FileExists(rtPath) {
         rtPath = bux_path_join(projectDir, "../stdlib/runtime.c");
     }
     if !FileExists(ioPath) {
         ioPath = bux_path_join(projectDir, "../stdlib/io.c");
     }
+
+    // Compile with cc
+    PrintLine("Compiling C...");
+    let outBin: String = bux_path_join(buildDir, outName);
+    var ccBuf: StringBuilder = StringBuilder_NewCap(512);
+    StringBuilder_Append(&ccBuf, "cc -O2 -pthread -o ");
+    StringBuilder_Append(&ccBuf, outBin);
+    StringBuilder_Append(&ccBuf, " ");
+    StringBuilder_Append(&ccBuf, cFile);
+    StringBuilder_Append(&ccBuf, " ");
     if FileExists(rtPath) {
-        StringBuilder_Append(&linkBuf, rtPath);
+        StringBuilder_Append(&ccBuf, rtPath);
-        StringBuilder_Append(&linkBuf, " ");
+        StringBuilder_Append(&ccBuf, " ");
     }
     if FileExists(ioPath) {
-        StringBuilder_Append(&linkBuf, ioPath);
+        StringBuilder_Append(&ccBuf, ioPath);
-        StringBuilder_Append(&linkBuf, " ");
+        StringBuilder_Append(&ccBuf, " ");
     }
-    StringBuilder_Append(&linkBuf, "-lm");
+    StringBuilder_Append(&ccBuf, "-lm");
-    let linkRc: int = bux_system(StringBuilder_Build(&linkBuf));
+    let ccRc: int = bux_system(StringBuilder_Build(&ccBuf));
-    if linkRc != 0 {
+    if ccRc != 0 {
-        PrintLine("Error: Linking failed");
+        PrintLine("Error: C compilation failed");
         return 1;
     }
 
@@ -693,7 +757,7 @@ func Cli_Run(args: *String, argCount: int) -> int {
         PrintLine("  Parser     ✅ 1004 lines");
         PrintLine("  Sema       ✅  393 lines");
         PrintLine("  HirLower   ✅  307 lines");
-        PrintLine("  CBackend   ✅  264 lines");
+        PrintLine("  CBackend   ✅  585 lines");
         PrintLine("  Total: 3830 lines of Bux");
         return 0;
     }
@@ -716,7 +780,7 @@ func Cli_Run(args: *String, argCount: int) -> int {
 
     if String_Eq(cmd, "build") {
         let src: String = "src/Main.bux";
-        let out: String = "build/main.nim";
+        let out: String = "build/main";
         if argCount >= 3 { src = args[2]; }
         if argCount >= 4 { out = args[3]; }
         return Cli_Build(src, out);

src_bux/hir.bux

@@ -115,6 +115,10 @@ struct HirConst {
     value: int;
 }
 
+struct HirEnum {
+    name: String;
+}
+
 struct HirModule {
     funcCount: int;
     funcs: *HirFunc;
@@ -123,6 +127,7 @@ struct HirModule {
     structCount: int;
     structs: *HirStruct;
     enumCount: int;
+    enums: *HirEnum;
     constCount: int;
     consts: *HirConst;
 }

src_bux/hir_lower.bux

@@ -213,6 +213,16 @@ func Lcx_LowerExpr(ctx: *LowerCtx, expr: *Expr) -> *HirNode {
 
     // Field access
     if kind == ekField {
+        // Check if this is enum variant access: Color::Green
+        if expr.child1 != null as *Expr && expr.child1.kind == ekIdent {
+            let sym: Symbol = Scope_Lookup(ctx.scope, expr.child1.strValue);
+            if sym.decl != null as *Decl && sym.decl.kind == dkEnum {
+                // Emit as variable reference: Color_Green
+                n.kind = hVar;
+                n.strValue = String_Concat(String_Concat(expr.child1.strValue, "_"), expr.strValue);
+                return n;
+            }
+        }
         n.kind = hFieldPtr;
         n.child1 = Lcx_LowerExpr(ctx, expr.child1);
         n.strValue = expr.strValue;
@@ -543,6 +553,8 @@ func HirLower_LowerModule(mod: *Module, sema: *Sema) -> *HirModule {
     hm.funcs = ctx.funcs;
     hm.structCount = 0;
     hm.structs = bux_alloc(64 as uint * sizeof(HirStruct)) as *HirStruct;
+    hm.enumCount = 0;
+    hm.enums = bux_alloc(64 as uint * sizeof(HirEnum)) as *HirEnum;
     hm.constCount = 0;
     hm.consts = bux_alloc(512 as uint * sizeof(HirConst)) as *HirConst;
 
@@ -628,7 +640,25 @@ func HirLower_LowerModule(mod: *Module, sema: *Sema) -> *HirModule {
             hm.constCount = hm.constCount + 1;
         }
         if decl.kind == dkEnum {
+            let ei: int = hm.enumCount;
+            hm.enums[ei].name = decl.strValue;
             hm.enumCount = hm.enumCount + 1;
+            // Emit enum variants as constants: EnumName_VariantName = value
+            var vi: int = 0;
+            while vi < decl.variantCount && hm.constCount < 512 {
+                var vname: String = "";
+                if vi == 0 { vname = decl.variant0.name; }
+                if vi == 1 { vname = decl.variant1.name; }
+                if vi == 2 { vname = decl.variant2.name; }
+                if vi == 3 { vname = decl.variant3.name; }
+                if !String_Eq(vname, "") {
+                    let ci: int = hm.constCount;
+                    hm.consts[ci].name = String_Concat(String_Concat(decl.strValue, "_"), vname);
+                    hm.consts[ci].value = vi;
+                    hm.constCount = hm.constCount + 1;
+                }
+                vi = vi + 1;
+            }
         }
         decl = decl.childDecl2;
     }

src_bux/sema.bux

@@ -96,7 +96,10 @@ func Sema_ResolveType(sema: *Sema, te: *TypeExpr) -> int {
 
 func Sema_IsNumeric(kind: int) -> bool {
     if kind == tyUnknown || kind == tyNamed || kind == tyTypeParam { return true; }
-    return kind >= tyInt8 && kind <= tyUInt64;
+    if kind == tyInt8 || kind == tyInt16 || kind == tyInt32 || kind == tyInt64 || kind == tyInt { return true; }
+    if kind == tyUInt8 || kind == tyUInt16 || kind == tyUInt32 || kind == tyUInt64 || kind == tyUInt { return true; }
+    if kind == tyFloat32 || kind == tyFloat64 { return true; }
+    return false;
 }
 
 func Sema_IsBool(kind: int) -> bool {
@@ -328,9 +331,12 @@ func Sema_CheckStmt(sema: *Sema, stmt: *Stmt) {
             let retType: int = Sema_CheckExpr(sema, stmt.child1);
             if sema.currentRetType != tyUnknown && retType != tyUnknown {
                 if retType != sema.currentRetType {
-                    // Be permissive: allow numeric widening, pointer/named mismatch
+                    // Be permissive: allow numeric widening, pointer compatibility
                     if !Sema_IsNumeric(retType) || !Sema_IsNumeric(sema.currentRetType) {
-                        if retType != sema.currentRetType {
+                        // Allow pointer-type compatibility (String <-> *T, *T <-> *U)
+                        let retIsPtr: bool = retType == tyPointer || retType == tyStr;
+                        let expectedIsPtr: bool = sema.currentRetType == tyPointer || sema.currentRetType == tyStr;
+                        if !retIsPtr || !expectedIsPtr {
                             Sema_EmitError(sema, stmt.line, stmt.column, "return type mismatch");
                         }
                     }