show multiple parse errors if exist (#687)

> multisyntaxerrors.jl
```julia
function f(W,X,Y)
    s = 0
    for i = 1:10
        s += g(W[i]*f(X[end-1] + Y[end÷2+]),
               W[i+1]*f(X[end-2] + Y[end÷2]) +,
               W[i+2]*f(X[end-3] + Y[end÷2-3]))
    end
    return s
end
```
```julia
julia> report_file("../JETLS/multisyntaxerrors.jl")
[...]
═════ 2 toplevel errors found ═════
┌ @ multisyntaxerrors.jl:4
│ # Error @ multisyntaxerrors.jl:4:42
│     for i = 1:10
│         s += g(W[i]*f(X[end-1] + Y[end÷2+]),
│ #                                        ╙ ── unexpected `]`
└──────────────────────
┌ @ multisyntaxerrors.jl:5
│ # Error @ multisyntaxerrors.jl:5:47
│         s += g(W[i]*f(X[end-1] + Y[end÷2+]),
│                W[i+1]*f(X[end-2] + Y[end÷2]) +,
│ #                                             ╙ ── unexpected `,`
└──────────────────────
```

src/toplevel/virtualprocess.jl

@@ -21,18 +21,19 @@ function Base.getproperty(er::ToplevelErrorReport, sym::Symbol)
     end
 end
 
-struct SyntaxErrorReport <: ToplevelErrorReport
-    err::JuliaSyntax.ParseError
+struct ParseErrorReport <: ToplevelErrorReport
+    diagnostic::JuliaSyntax.Diagnostic
+    source::JuliaSyntax.SourceFile
     file::String
     line::Int
-    function SyntaxErrorReport(err::JuliaSyntax.ParseError)
-        lnn = JuliaSyntax.source_location(LineNumberNode, err.source,
-            JuliaSyntax.first_byte(first(err.diagnostics)))
-        return new(err, String(lnn.file::Symbol), lnn.line)
+    function ParseErrorReport(diagnostic::JuliaSyntax.Diagnostic, source::JuliaSyntax.SourceFile)
+        line = JuliaSyntax.source_line(source, JuliaSyntax.first_byte(diagnostic))
+        return new(diagnostic, source, source.filename::String, line)
     end
 end
 # don't show stacktrace for syntax errors
-print_report(io::IO, report::SyntaxErrorReport) = showerror(io, report.err)
+print_report(io::IO, report::ParseErrorReport) =
+    JuliaSyntax.show_diagnostic(io, report.diagnostic, report.source)
 
 # TODO Use JuliaLowering.jl here
 struct LoweringErrorReport <: ToplevelErrorReport
@@ -586,19 +587,17 @@ function _virtual_process!(res::VirtualProcessResult,
     end
 
     s = String(s)::String
-    parsed = try
-        JuliaSyntax.parseall(Expr, s; filename)
-    catch err
-        err isa JuliaSyntax.ParseError || rethrow(err)
-        err
-    end
-
-    if parsed isa JuliaSyntax.ParseError
-        # if there's any syntax error, try to identify all the syntax error location
-        push!(res.toplevel_error_reports, SyntaxErrorReport(parsed))
-    else
+    stream = JuliaSyntax.ParseStream(s)
+    JuliaSyntax.parse!(stream; rule=:all)
+    if isempty(stream.diagnostics)
+        parsed = JuliaSyntax.build_tree(Expr, stream; filename)
         @assert isexpr(parsed, :toplevel)
         _virtual_process!(res, parsed, filename, analyzer, config, context, pkg_mod_depth)
+    else
+        source = JuliaSyntax.SourceFile(stream; filename)
+        for diagnostic in stream.diagnostics
+            push!(res.toplevel_error_reports, ParseErrorReport(diagnostic, source))
+        end
     end
 
     with_toplevel_logger(config) do @nospecialize(io)

test/toplevel/test_virtualprocess.jl

@@ -13,9 +13,27 @@ include("../setup.jl")
 
         res = report_text(s)
         report = only(res.res.toplevel_error_reports)
-        @test report isa SyntaxErrorReport
+        @test report isa ParseErrorReport
         @test report.line == 5
     end
+
+    # report multiple syntax errors if exist
+    let s = """
+        function f(W,X,Y)
+            s = 0
+            for i = 1:10
+                s += g(W[i]*f(X[end-1] + Y[end÷2+]),
+                    W[i+1]*f(X[end-2] + Y[end÷2]) +,
+                    W[i+2]*f(X[end-3] + Y[end÷2-3]))
+            end
+            return s
+        end
+        """ |> strip
+
+        res = report_text(s)
+        @test length(res.res.toplevel_error_reports) == 2
+        @test all(r -> r isa ParseErrorReport, res.res.toplevel_error_reports)
+    end
 end
 
 @testset "virtualize module context" begin

test/ui/test_print.jl

@@ -19,17 +19,19 @@ end
         res = report_text(src, @__FILE__)
         print_reports(io, res.res.toplevel_error_reports)
         let s = String(take!(io))
-            @test occursin("1 toplevel error found", s)
+            @test occursin("2 toplevel errors found", s)
             @test occursin(Regex("@ $(@__FILE__):\\d"), s)
             @test occursin("invalid identifier", s)
+            @test occursin("Expected `end`", s)
         end
 
         res = report_text(src, "foo")
         print_reports(io, res.res.toplevel_error_reports)
         let s = String(take!(io))
-            @test occursin("1 toplevel error found", s)
+            @test occursin("2 toplevel errors found", s)
             @test occursin(r"@ foo:\d", s)
             @test occursin("invalid identifier", s)
+            @test occursin("Expected `end`", s)
         end
     end
 end