Merge pull request 'feat/selfhost-sema-error-recovery' (#2) from feat/selfhost-sema-error-recovery into main

Reviewed-on: https://git.bara-lang.org/bux-lang/bux-lang/pulls/2

_test_call_args/bux.toml

@@ -0,0 +1,4 @@
+[Package]
+Name    = "call_args"
+Version = "0.1.0"
+Type    = "bin"

_test_call_args/src/Main.bux

@@ -0,0 +1,9 @@
+extern func PrintInt(n: int);
+extern func PrintLine(s: String);
+
+func Main() -> int {
+    PrintInt("hello");
+    PrintLine(42);
+    PrintInt(true);
+    return 0;
+}

_test_parse_recovery/bux.toml

@@ -0,0 +1,4 @@
+[Package]
+Name    = "parse_recovery"
+Version = "0.1.0"
+Type    = "bin"

_test_parse_recovery/src/Main.bux

@@ -0,0 +1,18 @@
+func Good() -> int {
+    return 1;
+}
+
+func Bad() -> int {
+    let x: int = ;
+    return 0;
+}
+
+func AlsoBad() -> int {
+    let y: int = 5 + ;
+    let z: int = 6;
+    return y;
+}
+
+func AlsoGood() -> int {
+    return 2;
+}

src/ast.bux

@@ -373,6 +373,16 @@ module Ast {
         // Struct fields (up to 256)
     }
 
+    // ---------------------------------------------------------------------------
+    // Parser diagnostic (recoverable errors collected during parsing)
+    // ---------------------------------------------------------------------------
+    struct ParserDiag {
+        line: uint32,
+        column: uint32,
+        message: String,
+        severity: int,  /* 0=error (fatal), 1=warning (recoverable) */
+    }
+
     // ---------------------------------------------------------------------------
     // Module — AST root
     // ---------------------------------------------------------------------------
@@ -381,6 +391,8 @@ module Ast {
         path: String,            // path segments joined
         itemCount: int,
         firstItem: *Decl,
+        diagCount: int,
+        diags: *ParserDiag,
     }
 
     // ---------------------------------------------------------------------------

src/cli.bux

@@ -358,6 +358,28 @@ module Cli {
 // Import the compiler pipeline
 // In self-hosting mode, these are compiled together from src/
 
+// ---------------------------------------------------------------------------
+// Report parser diagnostics attached to a module (Rust-style, with snippets).
+// Returns the number of diagnostics reported (0 = clean).
+// ---------------------------------------------------------------------------
+
+func Cli_ReportParseDiags(mod: *Module, sourceName: String) -> int {
+    if mod == null as *Module { return 0; }
+    if mod.diagCount == 0 { return 0; }
+    var i: int = 0;
+    while i < mod.diagCount {
+        let diag: Diagnostic = Diagnostic {
+            message: mod.diags[i].message,
+            line: mod.diags[i].line,
+            column: mod.diags[i].column,
+            severity: 0,
+        };
+        Diagnostic_Print(&diag, sourceName);
+        i = i + 1;
+    }
+    return mod.diagCount;
+}
+
 // ---------------------------------------------------------------------------
 // Compile a single .bux source file
 // ---------------------------------------------------------------------------
@@ -389,6 +411,7 @@ func Cli_Compile(source: String, sourceName: String, targetTriple: String) -> St
         PrintLine("Parse failed");
         return "";
     }
+    if Cli_ReportParseDiags(mod, sourceName) > 0 { return ""; }
     PrintLine("  Parse done");
 
     // Flatten module wrappers: find module decl and hoist its children
@@ -551,6 +574,7 @@ func Cli_Check(srcPath: String) -> int {
         PrintLine("Parse failed");
         return 1;
     }
+    if Cli_ReportParseDiags(mod, srcPath) > 0 { return 1; }
     PrintLine("  Parse done");
 
     // Flatten module wrappers
@@ -635,6 +659,7 @@ func Cli_CompileSource(source: String, sourceName: String) -> *HirModule {
         PrintLine(sourceName);
         return null as *HirModule;
     }
+    if Cli_ReportParseDiags(mod, sourceName) > 0 { return null as *HirModule; }
 
     // Phase 2b: macro expand
     let macEx3: *MacroExpander = MacroExpand_ExpandModule(mod);
@@ -836,6 +861,10 @@ func Cli_MergeFileInto(target: *Module, path: String, skipNames: *String, skipCo
     if Lexer_DiagCount(lex) > 0 { return 0; }
     let mod: *Module = Parser_Parse(lex.tokens, lex.tokenCount);
     if mod == null as *Module { return 0; }
+    // Report parse diags but keep merging the recovered decls: this path
+    // handles stdlib/dependency files, and the parser currently emits
+    // recoverable diags for valid multi-line braced imports there.
+    discard Cli_ReportParseDiags(mod, path);
     // Tag every decl from this file for #line maps
     var stamp: *Decl = mod.firstItem;
     while stamp != null as *Decl {
@@ -1928,6 +1957,8 @@ func Cli_BuildProject(projectDir: String, targetTriple: String, isRelease: bool,
     userMerged.path = "";
     userMerged.itemCount = 0;
     userMerged.firstItem = null as *Decl;
+    userMerged.diagCount = 0;
+    userMerged.diags = null as *ParserDiag;
 
     // Parse each file and merge declarations into userMerged module
     var i: int = 0;
@@ -1962,6 +1993,7 @@ func Cli_BuildProject(projectDir: String, targetTriple: String, isRelease: bool,
             PrintLine(path);
             return 1;
         }
+        if Cli_ReportParseDiags(mod, path) > 0 { return 1; }
         // Tag decls with this source path for multi-file #line
         var stampUser: *Decl = mod.firstItem;
         while stampUser != null as *Decl {
@@ -2031,6 +2063,8 @@ func Cli_BuildProject(projectDir: String, targetTriple: String, isRelease: bool,
     merged.path = "";
     merged.itemCount = 0;
     merged.firstItem = null as *Decl;
+    merged.diagCount = 0;
+    merged.diags = null as *ParserDiag;
 
     // Find and merge ALL stdlib declarations
     let stdlibDir: String = Cli_FindStdlibDir(projectDir);

src/parser.bux

@@ -30,13 +30,6 @@ module Parser {
         macroTemplateMode: bool,  // allows $(…)* in macro! bodies
     }
 
-    struct ParserDiag {
-        line: uint32,
-        column: uint32,
-        message: String,
-        severity: int,  /* 0=error (fatal), 1=warning (recoverable) */
-    }
-
     // ---------------------------------------------------------------------------
     // Token helpers
     // ---------------------------------------------------------------------------
@@ -120,7 +113,7 @@ module Parser {
             return parserAdvance(p);
         }
         let tok: LexToken = parserCurToken(p);
-        if p.diagCount < 256 {
+        if p.diagCount < 256 && p.diags != null as *ParserDiag {
             p.diags[p.diagCount] = ParserDiag {
                 line: tok.line, column: tok.column, message: msg, severity: 1
             };
@@ -130,7 +123,7 @@ module Parser {
     }
 
     func parserEmitDiag(p: *Parser, line: uint32, col: uint32, msg: String) {
-        if p.diagCount < 256 {
+        if p.diagCount < 256 && p.diags != null as *ParserDiag {
             p.diags[p.diagCount] = ParserDiag {
                 line: line, column: col, message: msg, severity: 1
             };
@@ -149,7 +142,7 @@ module Parser {
         if tok.kind == tkIdent || parserIsKeyword(tok.kind) {
             return parserAdvance(p);
         }
-        if p.diagCount < 256 {
+        if p.diagCount < 256 && p.diags != null as *ParserDiag {
             p.diags[p.diagCount] = ParserDiag {
                 line: tok.line, column: tok.column, message: msg, severity: 1
             };
@@ -2175,6 +2168,7 @@ module Parser {
         parserParseTypeParams(p, d);
 
         discard parserExpect(p, tkLBrace, "expected '{'");
+        var lastWasComma: bool = false;
         while !parserCheck(p, tkRBrace) && parserPeek(p, 0) != tkEndOfFile {
             if fieldCount >= 256 {
                 parserEmitDiag(p, line, col, "too many struct fields (max 255)");
@@ -2182,13 +2176,17 @@ module Parser {
             }
             if parserCheck(p, tkNewLine) { discard parserAdvance(p); continue; }
             if parserCheck(p, tkSemicolon) { discard parserAdvance(p); continue; }
+            // Commas are also valid field separators (incl. trailing comma before '}')
+            if parserCheck(p, tkComma) {
+                if fieldCount == 0 || lastWasComma {
+                    parserEmitDiag(p, parserCurToken(p).line, parserCurToken(p).column, "expected field name");
+                }
+                lastWasComma = true;
+                discard parserAdvance(p);
+                continue;
+            }
             let beforePos: int = p.pos;
             let fName: LexToken = parserExpectIdentOrKeyword(p, "expected field name");
-            if fieldCount >= 250 && fieldCount <= 256 {
-                PrintLine(String_Concat("RAW fieldCount=", bux_int_to_str(fieldCount as int64)));
-                PrintLine(String_Concat("RAW fName=", fName.text));
-                PrintLine(String_Concat("RAW pos=", bux_int_to_str(p.pos as int64)));
-            }
             discard parserExpect(p, tkColon, "expected ':' in struct field");
             let fType: *TypeExpr = parserParseType(p);
             parserMatch(p, tkSemicolon);
@@ -2201,6 +2199,7 @@ module Parser {
             d.fields[fieldCount].name = fName.text;
             d.fields[fieldCount].refFieldType = fType;
             fieldCount = fieldCount + 1;
+            lastWasComma = false;
         }
         d.fieldCount = fieldCount;
         discard parserExpect(p, tkRBrace, "expected '}'");
@@ -2281,9 +2280,10 @@ module Parser {
         d.isPublic = isPublic;
 
         // Parse path: Std::Io::PrintLine
+        // Stop before `::{` (multi-import) and `::*` (glob import)
         var pathStr: String = "";
         var segCount: int = 0;
-        while parserCheck(p, tkIdent) || (segCount > 0 && parserCheck(p, tkColonColon) && parserPeek(p, 1) != tkLBrace) {
+        while parserCheck(p, tkIdent) || (segCount > 0 && parserCheck(p, tkColonColon) && parserPeek(p, 1) != tkLBrace && parserPeek(p, 1) != tkStar) {
             if segCount > 0 {
                 discard parserAdvance(p); // ::
                 if String_Len(pathStr) > 0 {
@@ -2315,6 +2315,10 @@ module Parser {
                     names = String_Concat(names, ",");
                     if !parserMatch(p, tkComma) { break; }
                 }
+                // Allow newlines before the closing brace (multi-line import lists)
+                while parserCheck(p, tkNewLine) {
+                    discard parserAdvance(p);
+                }
                 discard parserExpect(p, tkRBrace, "expected '}'");
                 d.useNames = names;
                 d.useKind = 2; // ukMulti
@@ -2373,6 +2377,8 @@ module Parser {
         var lastMethod: *Decl = null as *Decl;
         while !parserCheck(p, tkRBrace) && parserPeek(p, 0) != tkEndOfFile {
             if parserCheck(p, tkNewLine) { discard parserAdvance(p); continue; }
+            // Bodyless method signatures end with ';'
+            if parserCheck(p, tkSemicolon) { discard parserAdvance(p); continue; }
             if parserCheck(p, tkFunc) {
                 let m: *Decl = parserParseFuncDecl(p, false, false, false);
                 if methods == null as *Decl {
@@ -2827,34 +2833,9 @@ module Parser {
             }
         }
 
-        /* Print fatal parser diagnostics (severity == 0) or if nothing valid was parsed */
+        // Attach parser diagnostics to the module; the CLI reports them
-        if p.diagCount > 0 && mod.itemCount == 0 {
+        mod.diagCount = p.diagCount;
-            var di: int = 0;
+        mod.diags = p.diags;
-            while di < p.diagCount {
-                let d: ParserDiag = p.diags[di];
-                Print("error: ");
-                PrintLine(d.message);
-                Print("  --> <input>:");
-                PrintInt(d.line as int64);
-                Print(":");
-                PrintInt(d.column as int64);
-                PrintLine("");
-                Print("   |");
-                PrintLine("");
-                Print(" ");
-                PrintInt(d.line as int64);
-                Print(" | <source unavailable>");
-                PrintLine("");
-                Print("   | ");
-                var sp: uint32 = 0;
-                while sp < d.column - 1 && sp < 120 {
-                    Print(" ");
-                    sp = sp + 1;
-                }
-                PrintLine("^");
-                di = di + 1;
-            }
-        }
 
         return mod;
     }

src/sema.bux

@@ -210,6 +210,9 @@ module Sema {
     // Display-name helper for assignment diagnostics.
     func Sema_TypeNameForDiag(te: *TypeExpr, kind: int) -> String {
         if te != null as *TypeExpr {
+            // tekFunc TypeExprs have no typeName set (parser leaves it unset) —
+            // never touch te.typeName for them.
+            if te.kind == tekFunc { return "func"; }
             if te.kind == tekPointer && te.pointerPointee != null as *TypeExpr {
                 return String_Concat(te.pointerPointee.typeName, "*");
             }
@@ -225,6 +228,25 @@ module Sema {
         return "?";
     }
 
+    // Assignability for diagnostics: strict numeric widening, bool family,
+    // exact pointer kind, named types by name (best-effort when refType available).
+    func Sema_CanAssignTo(sema: *Sema, fromKind: int, fromTe: *TypeExpr, toTe: *TypeExpr) -> bool {
+        if fromKind == tyUnknown { return true; }
+        if toTe == null as *TypeExpr { return true; }
+        let toKind: int = Sema_ResolveType(sema, toTe);
+        if toKind == tyUnknown { return true; }
+        if fromKind == tyNamed && toKind == tyNamed {
+            if fromTe != null as *TypeExpr && !String_Eq(fromTe.typeName, "") {
+                return String_Eq(fromTe.typeName, toTe.typeName);
+            }
+            return true;
+        }
+        if fromKind == toKind { return true; }
+        if Sema_IsStrictNumeric(fromKind) && Sema_IsStrictNumeric(toKind) { return true; }
+        if Sema_IsBool(fromKind) && Sema_IsBool(toKind) { return true; }
+        return false;
+    }
+
     // ---------------------------------------------------------------------------
     // Block checking helper
     // ---------------------------------------------------------------------------
@@ -338,6 +360,34 @@ module Sema {
             i = i + 1;
         }
 
+        // Report named args that match no parameter
+        var checkArg: *ExprList = expr.callArgs;
+        while checkArg != null as *ExprList {
+            if !String_Eq(checkArg.argName, "") {
+                var foundName: bool = false;
+                var j: int = 0;
+                while j < decl.paramCount {
+                    var pj: *Param = null as *Param;
+                    if j == 0 { pj = &decl.param0; }
+                    else if j == 1 { pj = &decl.param1; }
+                    else if j == 2 { pj = &decl.param2; }
+                    else if j == 3 { pj = &decl.param3; }
+                    else if j == 4 { pj = &decl.param4; }
+                    else if j == 5 { pj = &decl.param5; }
+                    else if j == 6 { pj = &decl.param6; }
+                    else if j == 7 { pj = &decl.param7; }
+                    else if j == 8 { pj = &decl.param8; }
+                    if String_Eq(checkArg.argName, pj.name) { foundName = true; }
+                    j = j + 1;
+                }
+                if !foundName {
+                    Sema_EmitError(sema, expr.line, expr.column,
+                        String_Concat("unknown argument name '", String_Concat(checkArg.argName, "'")));
+                }
+            }
+            checkArg = checkArg.next;
+        }
+
         expr.callArgs = newFirst;
         expr.callArgCount = newCount;
     }
@@ -1035,9 +1085,57 @@ module Sema {
         if kind == ekCall {
             let calleeType: int = Sema_CheckExpr(sema, expr.child1);
             Sema_ResolveCallArgs(sema, expr);
+            // Resolve callee decl for call-argument checking: direct calls to
+            // non-generic named functions only (inference handles generics).
+            var callDecl: *Decl = null as *Decl;
+            if expr.child1 != null as *Expr && expr.child1.kind == ekIdent {
+                let callSym: Symbol = Scope_Lookup(sema.scope, expr.child1.strValue);
+                if callSym.kind == skFunc && callSym.decl != null as *Decl {
+                    if callSym.decl.typeParamCount == 0 {
+                        callDecl = callSym.decl;
+                    }
+                }
+            }
+            // Arity check (runs after Sema_ResolveCallArgs so defaults/named args align)
+            if callDecl != null as *Decl && expr.callArgCount != callDecl.paramCount {
+                Sema_EmitError(sema, expr.line, expr.column,
+                    String_Concat("expected ", String_Concat(bux_int_to_str(callDecl.paramCount as int64),
+                    String_Concat(" arguments, got ", bux_int_to_str(expr.callArgCount as int64)))));
+                callDecl = null as *Decl;
+            }
+            var argIdx: int = 0;
             var arg: *ExprList = expr.callArgs;
             while arg != null as *ExprList {
-                discard Sema_CheckExpr(sema, arg.expr);
+                let argKind: int = Sema_CheckExpr(sema, arg.expr);
+                // Per-argument type check against the parameter type
+                if callDecl != null as *Decl && argIdx < callDecl.paramCount {
+                    let cp: *Param = Sema_DeclParam(callDecl, argIdx);
+                    if cp != null as *Param && cp.refParamType != null as *TypeExpr {
+                        // Skip conditions matching the bootstrap: unknown/named/typeparam
+                        // arg kinds, and *char8 -> String (C string interop).
+                        var argSkip: bool = false;
+                        if argKind == tyUnknown || argKind == tyNamed || argKind == tyTypeParam { argSkip = true; }
+                        // Function-typed params: selfhost cannot reliably type function
+                        // values (e.g. '&Double' is tyPointer) — defer like the bootstrap.
+                        if Sema_ResolveType(sema, cp.refParamType) == tyFunc { argSkip = true; }
+                        if !argSkip && argKind == tyPointer && Sema_ResolveType(sema, cp.refParamType) == tyStr {
+                            if arg.expr != null as *Expr && arg.expr.refType != null as *TypeExpr {
+                                if arg.expr.refType.kind == tekPointer && arg.expr.refType.pointerPointee != null as *TypeExpr {
+                                    if String_Eq(arg.expr.refType.pointerPointee.typeName, "char8") { argSkip = true; }
+                                }
+                            }
+                        }
+                        if !argSkip && arg.expr != null as *Expr && !Sema_CanAssignTo(sema, argKind, arg.expr.refType, cp.refParamType) {
+                            let wantName: String = Sema_TypeNameForDiag(cp.refParamType, Sema_ResolveType(sema, cp.refParamType));
+                            let gotName: String = Sema_TypeNameForDiag(arg.expr.refType, argKind);
+                            Sema_EmitError(sema, arg.expr.line, arg.expr.column,
+                                String_Concat("argument ", String_Concat(bux_int_to_str((argIdx + 1) as int64),
+                                String_Concat(": expected ", String_Concat(wantName,
+                                String_Concat(", got ", gotName))))));
+                        }
+                    }
+                }
+                argIdx = argIdx + 1;
                 arg = arg.next;
             }
             // Borrow check: reject double mutable borrow in @[Checked] functions
@@ -1157,6 +1255,10 @@ module Sema {
 
         // Struct init: TypeName { field: value, ... }
         if kind == ekStructInit {
+            let te: *TypeExpr = bux_alloc(sizeof(TypeExpr)) as *TypeExpr;
+            te.kind = tekNamed;
+            te.typeName = expr.structName;
+            expr.refType = te;
             return tyNamed;
         }
 
@@ -1495,31 +1597,12 @@ module Sema {
             }
             // Assignment check: annotation vs initializer (skip when either side is unknown)
             if stmt.refStmtType != null as *TypeExpr && initType != tyUnknown {
-                let annotKind: int = Sema_ResolveType(sema, stmt.refStmtType);
+                if !Sema_CanAssignTo(sema, initType, stmt.child1.refType, stmt.refStmtType) {
-                if annotKind != tyUnknown {
+                    let gotName: String = Sema_TypeNameForDiag(stmt.child1.refType, initType);
-                    var mismatch: bool = false;
+                    let wantName: String = Sema_TypeNameForDiag(stmt.refStmtType, Sema_ResolveType(sema, stmt.refStmtType));
-                    if initType == tyNamed && annotKind == tyNamed {
+                    let msg: String = String_Concat("cannot assign ",
-                        // Both named: kinds are equal, compare type names (when available).
+                        String_Concat(gotName, String_Concat(" to ", wantName)));
-                        if stmt.child1 != null as *Expr && stmt.child1.refType != null as *TypeExpr {
+                    Sema_EmitError(sema, stmt.line, stmt.column, msg);
-                            if !String_Eq(stmt.child1.refType.typeName, "") &&
-                            !String_Eq(stmt.child1.refType.typeName, stmt.refStmtType.typeName) {
-                                mismatch = true;
-                            }
-                        }
-                    } else if initType != annotKind {
-                        let numericOk: bool = Sema_IsStrictNumeric(initType) && Sema_IsStrictNumeric(annotKind);
-                        let boolOk: bool = Sema_IsBool(initType) && Sema_IsBool(annotKind);
-                        if !numericOk && !boolOk {
-                            mismatch = true;
-                        }
-                    }
-                    if mismatch {
-                        let gotName: String = Sema_TypeNameForDiag(stmt.child1.refType, initType);
-                        let wantName: String = Sema_TypeNameForDiag(stmt.refStmtType, annotKind);
-                        let msg: String = String_Concat("cannot assign ",
-                            String_Concat(gotName, String_Concat(" to ", wantName)));
-                        Sema_EmitError(sema, stmt.line, stmt.column, msg);
-                    }
                 }
             }
             sym.isMutable = stmt.boolValue;