Fix issue 21284: report "no property" error at identifier location

The "no property `X` for type `Y`" error for enum member access was
reported at the location of the enum type expression instead of the
invalid identifier, e.g. across:

    auto x =
        E
        .
        three;

it reported the error on the "E" line instead of the "three" line.

- Add identLoc to DotIdExp, set by the parser from the identifier's
  own token location.
- Thread identLoc through dotExp() and use it (falling back to the
  previous location when unset) when reporting the "no property"
  error for TypeEnum.
- Add fail_compilation test diag21284.d.

Based on the diagnosis and approach explored in #22740 by
Jay-Lokhande.

Fixes https://issues.dlang.org/show_bug.cgi?id=21284

Author: usefahmed07

compiler/include/dmd/expression.h

@@ -688,8 +688,9 @@ class DotIdExp final : public UnaExp
     d_bool noderef;       // true if the result of the expression will never be dereferenced
     d_bool wantsym;       // do not replace Symbol with its initializer during semantic()
     d_bool arrow;         // ImportC: if -> instead of .
+    Loc identLoc;         // location of `ident` itself (may differ from `loc`, e.g. across multiple lines)
 
-    static DotIdExp *create(Loc loc, Expression *e, Identifier *ident);
+    static DotIdExp *create(Loc loc, Expression *e, Identifier *ident, Loc identLoc = Loc());
     void accept(Visitor *v) override { v->visit(this); }
 };
 

compiler/src/dmd/expression.d

@@ -2191,16 +2191,18 @@ extern (C++) final class DotIdExp : UnaExp
     bool noderef;       // true if the result of the expression will never be dereferenced
     bool wantsym;       // do not replace Symbol with its initializer during semantic()
     bool arrow;         // ImportC: if -> instead of .
+    Loc identLoc;       // location of `ident` itself (may differ from `loc`, e.g. across multiple lines)
 
-    extern (D) this(Loc loc, Expression e, Identifier ident) @safe
+    extern (D) this(Loc loc, Expression e, Identifier ident, Loc identLoc = Loc.init) @safe
     {
         super(loc, EXP.dotIdentifier, e);
         this.ident = ident;
+        this.identLoc = identLoc.isValid() ? identLoc : loc;
     }
 
-    static DotIdExp create(Loc loc, Expression e, Identifier ident) @safe
+    static DotIdExp create(Loc loc, Expression e, Identifier ident, Loc identLoc = Loc.init) @safe
     {
-        return new DotIdExp(loc, e, ident);
+        return new DotIdExp(loc, e, ident, identLoc);
     }
 
     override void accept(Visitor v)

compiler/src/dmd/expressionsem.d

@@ -16528,7 +16528,7 @@ Expression dotIdSemanticProp(DotIdExp exp, Scope* sc, bool gag)
 
         const flag = cast(DotExpFlag) (exp.noderef * DotExpFlag.noDeref | gag * DotExpFlag.gag);
 
-        Expression e = dotExp(exp.e1.type, sc, exp.e1, exp.ident, flag);
+        Expression e = dotExp(exp.e1.type, sc, exp.e1, exp.ident, flag, exp.identLoc);
         if (e)
         {
             e = e.expressionSemantic(sc);

compiler/src/dmd/parse.d

@@ -9371,6 +9371,7 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
                 if (token.value == TOK.identifier)
                 {
                     Identifier id = token.ident;
+                    const identLoc = token.loc;
 
                     nextToken();
                     if (token.value == TOK.not && peekNext() != TOK.is_ && peekNext() != TOK.in_)
@@ -9379,7 +9380,7 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
                         e = new AST.DotTemplateInstanceExp(loc, e, id, tiargs);
                     }
                     else
-                        e = new AST.DotIdExp(loc, e, id);
+                        e = new AST.DotIdExp(loc, e, id, identLoc);
                     continue;
                 }
                 if (token.value == TOK.new_)

compiler/src/dmd/typesem.d

@@ -6194,7 +6194,7 @@ void resolve(Type mt, Loc loc, Scope* sc, out Expression pe, out Type pt, out Ds
  * Returns:
  *  resulting expression with e.ident resolved
  */
-Expression dotExp(Type mt, Scope* sc, Expression e, Identifier ident, DotExpFlag flag)
+Expression dotExp(Type mt, Scope* sc, Expression e, Identifier ident, DotExpFlag flag, Loc identLoc = Loc.init)
 {
     enum LOGDOTEXP = false;
     if (LOGDOTEXP)
@@ -7045,11 +7045,12 @@ Expression dotExp(Type mt, Scope* sc, Expression e, Identifier ident, DotExpFlag
             Expression res = mt.sym.getMemtype(Loc.initial).dotExp(sc, e, ident, DotExpFlag.gag);
             if (!(flag & 1) && !res)
             {
+                const errLoc = identLoc.isValid() ? identLoc : e.loc;
                 if (auto ns = mt.sym.search_correct(ident))
-                    eSink.error(e.loc, "no property `%s` for type `%s`. Did you mean `%s.%s` ?", ident.toErrMsg(), mt.toErrMsg(), mt.toErrMsg(),
+                    eSink.error(errLoc, "no property `%s` for type `%s`. Did you mean `%s.%s` ?", ident.toErrMsg(), mt.toErrMsg(), mt.toErrMsg(),
                         ns.toErrMsg());
                 else
-                    eSink.error(e.loc, "no property `%s` for type `%s`", ident.toErrMsg(),
+                    eSink.error(errLoc, "no property `%s` for type `%s`", ident.toErrMsg(),
                         mt.toErrMsg());
 
                 eSink.errorSupplemental(mt.sym.loc, "%s `%s` defined here",

compiler/test/fail_compilation/diag21284.d

@@ -0,0 +1,17 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/diag21284.d(16): Error: no property `three` for type `E`
+fail_compilation/diag21284.d(9):        enum `E` defined here
+---
+*/
+// https://issues.dlang.org/show_bug.cgi?id=21284 (github issue)
+enum E { one, two }
+
+void test21284()
+{
+    auto x =
+        E
+        .
+        three;
+}