Handle compiler diagnostics in Rust (#2445)

16 files changed, 1044 insertions, 87 deletions

diff --git a/cli/BUILD.gn b/cli/BUILD.gn
index 7887624e2..45386f320 100644
--- a/cli/BUILD.gn
+++ b/cli/BUILD.gn
@@ -74,6 +74,7 @@ ts_sources = [
   "../js/core.ts",
   "../js/custom_event.ts",
   "../js/deno.ts",
+  "../js/diagnostics.ts",
   "../js/dir.ts",
   "../js/dispatch.ts",
   "../js/dispatch_minimal.ts",
diff --git a/cli/ansi.rs b/cli/ansi.rs
index 95b5e0694..b9e9fe123 100644
--- a/cli/ansi.rs
+++ b/cli/ansi.rs
@@ -1,6 +1,8 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+use ansi_term::Color::Black;
 use ansi_term::Color::Fixed;
 use ansi_term::Color::Red;
+use ansi_term::Color::White;
 use ansi_term::Style;
 use regex::Regex;
 use std::env;
@@ -43,6 +45,14 @@ pub fn italic_bold(s: String) -> impl fmt::Display {
   style.paint(s)
 }
 
+pub fn black_on_white(s: String) -> impl fmt::Display {
+  let mut style = Style::new();
+  if use_color() {
+    style = style.on(White).fg(Black);
+  }
+  style.paint(s)
+}
+
 pub fn yellow(s: String) -> impl fmt::Display {
   let mut style = Style::new();
   if use_color() {
@@ -61,6 +71,22 @@ pub fn cyan(s: String) -> impl fmt::Display {
   style.paint(s)
 }
 
+pub fn red(s: String) -> impl fmt::Display {
+  let mut style = Style::new();
+  if use_color() {
+    style = style.fg(Red);
+  }
+  style.paint(s)
+}
+
+pub fn grey(s: String) -> impl fmt::Display {
+  let mut style = Style::new();
+  if use_color() {
+    style = style.fg(Fixed(8));
+  }
+  style.paint(s)
+}
+
 pub fn bold(s: String) -> impl fmt::Display {
   let mut style = Style::new();
   if use_color() {
diff --git a/cli/compiler.rs b/cli/compiler.rs
index e1bb56130..0b6c278f9 100644
--- a/cli/compiler.rs
+++ b/cli/compiler.rs
@@ -1,4 +1,5 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+use crate::diagnostics::Diagnostic;
 use crate::msg;
 use crate::resources;
 use crate::startup_data;
@@ -7,7 +8,6 @@ use crate::tokio_util;
 use crate::worker::Worker;
 use deno::js_check;
 use deno::Buf;
-use deno::JSError;
 use futures::Future;
 use futures::Stream;
 use std::str;
@@ -87,7 +87,7 @@ pub fn compile_async(
   specifier: &str,
   referrer: &str,
   module_meta_data: &ModuleMetaData,
-) -> impl Future<Item = ModuleMetaData, Error = JSError> {
+) -> impl Future<Item = ModuleMetaData, Error = Diagnostic> {
   debug!(
     "Running rust part of compile_sync. specifier: {}, referrer: {}",
     &specifier, &referrer
@@ -136,14 +136,15 @@ pub fn compile_async(
   first_msg_fut
     .map_err(|_| panic!("not handled"))
     .and_then(move |maybe_msg: Option<Buf>| {
-      let _res_msg = maybe_msg.unwrap();
-
       debug!("Received message from worker");
 
-      // TODO res is EmitResult, use serde_derive to parse it. Errors from the
-      // worker or Diagnostics should be somehow forwarded to the caller!
-      // Currently they are handled inside compiler.ts with os.exit(1) and above
-      // with std::process::exit(1). This bad.
+      if let Some(msg) = maybe_msg {
+        let json_str = std::str::from_utf8(&msg).unwrap();
+        debug!("Message: {}", json_str);
+        if let Some(diagnostics) = Diagnostic::from_emit_result(json_str) {
+          return Err(diagnostics);
+        }
+      }
 
       let r = state.dir.fetch_module_meta_data(
         &module_meta_data_.module_name,
@@ -169,7 +170,7 @@ pub fn compile_sync(
   specifier: &str,
   referrer: &str,
   module_meta_data: &ModuleMetaData,
-) -> Result<ModuleMetaData, JSError> {
+) -> Result<ModuleMetaData, Diagnostic> {
   tokio_util::block_on(compile_async(
     state,
     specifier,
diff --git a/cli/diagnostics.rs b/cli/diagnostics.rs
new file mode 100644
index 000000000..af384f277
--- /dev/null
+++ b/cli/diagnostics.rs
@@ -0,0 +1,668 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+//! This module encodes TypeScript errors (diagnostics) into Rust structs and
+//! contains code for printing them to the console.
+use crate::ansi;
+use serde_json;
+use serde_json::value::Value;
+use std::fmt;
+
+// A trait which specifies parts of a diagnostic like item needs to be able to
+// generate to conform its display to other diagnostic like items
+pub trait DisplayFormatter {
+  fn format_category_and_code(&self) -> String;
+  fn format_message(&self, level: usize) -> String;
+  fn format_related_info(&self) -> String;
+  fn format_source_line(&self, level: usize) -> String;
+  fn format_source_name(&self, level: usize) -> String;
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct Diagnostic {
+  pub items: Vec<DiagnosticItem>,
+}
+
+impl Diagnostic {
+  /// Take a JSON value and attempt to map it to a
+  pub fn from_json_value(v: &serde_json::Value) -> Option<Self> {
+    if !v.is_object() {
+      return None;
+    }
+    let obj = v.as_object().unwrap();
+
+    let mut items = Vec::<DiagnosticItem>::new();
+    let items_v = &obj["items"];
+    if items_v.is_array() {
+      let items_values = items_v.as_array().unwrap();
+
+      for item_v in items_values {
+        items.push(DiagnosticItem::from_json_value(item_v));
+      }
+    }
+
+    Some(Self { items })
+  }
+
+  pub fn from_emit_result(json_str: &str) -> Option<Self> {
+    let v = serde_json::from_str::<serde_json::Value>(json_str)
+      .expect("Error decoding JSON string.");
+    let diagnostics_o = v.get("diagnostics");
+    if let Some(diagnostics_v) = diagnostics_o {
+      return Self::from_json_value(diagnostics_v);
+    }
+
+    None
+  }
+}
+
+impl fmt::Display for Diagnostic {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    let mut i = 0;
+    for item in &self.items {
+      if i > 0 {
+        writeln!(f)?;
+      }
+      write!(f, "{}", item.to_string())?;
+      i += 1;
+    }
+
+    if i > 1 {
+      write!(f, "\n\nFound {} errors.\n", i)?;
+    }
+
+    Ok(())
+  }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct DiagnosticItem {
+  /// The top level message relating to the diagnostic item.
+  pub message: String,
+
+  /// A chain of messages, code, and categories of messages which indicate the
+  /// full diagnostic information.
+  pub message_chain: Option<Box<DiagnosticMessageChain>>,
+
+  /// Other diagnostic items that are related to the diagnostic, usually these
+  /// are suggestions of why an error occurred.
+  pub related_information: Option<Vec<DiagnosticItem>>,
+
+  /// The source line the diagnostic is in reference to.
+  pub source_line: Option<String>,
+
+  /// Zero-based index to the line number of the error.
+  pub line_number: Option<i64>,
+
+  /// The resource name provided to the TypeScript compiler.
+  pub script_resource_name: Option<String>,
+
+  /// Zero-based index to the start position in the entire script resource.
+  pub start_position: Option<i64>,
+
+  /// Zero-based index to the end position in the entire script resource.
+  pub end_position: Option<i64>,
+  pub category: DiagnosticCategory,
+
+  /// This is defined in TypeScript and can be referenced via
+  /// [diagnosticMessages.json](https://github.com/microsoft/TypeScript/blob/master/src/compiler/diagnosticMessages.json).
+  pub code: i64,
+
+  /// Zero-based index to the start column on `line_number`.
+  pub start_column: Option<i64>,
+
+  /// Zero-based index to the end column on `line_number`.
+  pub end_column: Option<i64>,
+}
+
+impl DiagnosticItem {
+  pub fn from_json_value(v: &serde_json::Value) -> Self {
+    let obj = v.as_object().unwrap();
+
+    // required attributes
+    let message = obj
+      .get("message")
+      .and_then(|v| v.as_str().map(String::from))
+      .unwrap();
+    let category = DiagnosticCategory::from(
+      obj.get("category").and_then(Value::as_i64).unwrap(),
+    );
+    let code = obj.get("code").and_then(Value::as_i64).unwrap();
+
+    // optional attributes
+    let source_line = obj
+      .get("sourceLine")
+      .and_then(|v| v.as_str().map(String::from));
+    let script_resource_name = obj
+      .get("scriptResourceName")
+      .and_then(|v| v.as_str().map(String::from));
+    let line_number = obj.get("lineNumber").and_then(Value::as_i64);
+    let start_position = obj.get("startPosition").and_then(Value::as_i64);
+    let end_position = obj.get("endPosition").and_then(Value::as_i64);
+    let start_column = obj.get("startColumn").and_then(Value::as_i64);
+    let end_column = obj.get("endColumn").and_then(Value::as_i64);
+
+    let message_chain_v = obj.get("messageChain");
+    let message_chain = match message_chain_v {
+      Some(v) => DiagnosticMessageChain::from_json_value(v),
+      _ => None,
+    };
+
+    let related_information_v = obj.get("relatedInformation");
+    let related_information = match related_information_v {
+      Some(r) => {
+        let mut related_information = Vec::<DiagnosticItem>::new();
+        let related_info_values = r.as_array().unwrap();
+
+        for related_info_v in related_info_values {
+          related_information
+            .push(DiagnosticItem::from_json_value(related_info_v));
+        }
+
+        Some(related_information)
+      }
+      _ => None,
+    };
+
+    Self {
+      message,
+      message_chain,
+      related_information,
+      code,
+      source_line,
+      script_resource_name,
+      line_number,
+      start_position,
+      end_position,
+      category,
+      start_column,
+      end_column,
+    }
+  }
+}
+
+// TODO should chare logic with cli/js_errors, possibly with JSError
+// implementing the `DisplayFormatter` trait.
+impl DisplayFormatter for DiagnosticItem {
+  fn format_category_and_code(&self) -> String {
+    let category = match self.category {
+      DiagnosticCategory::Error => {
+        format!("- {}", ansi::red("error".to_string()))
+      }
+      DiagnosticCategory::Warning => "- warn".to_string(),
+      DiagnosticCategory::Debug => "- debug".to_string(),
+      DiagnosticCategory::Info => "- info".to_string(),
+      _ => "".to_string(),
+    };
+
+    let code = ansi::grey(format!(" TS{}:", self.code.to_string())).to_string();
+
+    format!("{}{} ", category, code)
+  }
+
+  fn format_message(&self, level: usize) -> String {
+    if self.message_chain.is_none() {
+      return format!("{:indent$}{}", "", self.message, indent = level);
+    }
+
+    let mut s = String::new();
+    let mut i = level / 2;
+    let mut item_o = self.message_chain.clone();
+    while item_o.is_some() {
+      let item = item_o.unwrap();
+      s.push_str(&std::iter::repeat(" ").take(i * 2).collect::<String>());
+      s.push_str(&item.message);
+      s.push('\n');
+      item_o = item.next.clone();
+      i += 1;
+    }
+    s.pop();
+
+    s
+  }
+
+  fn format_related_info(&self) -> String {
+    if self.related_information.is_none() {
+      return "".to_string();
+    }
+
+    let mut s = String::new();
+    let related_information = self.related_information.clone().unwrap();
+    for related_diagnostic in related_information {
+      let rd = &related_diagnostic;
+      s.push_str(&format!(
+        "\n{}{}{}\n",
+        rd.format_source_name(2),
+        rd.format_source_line(4),
+        rd.format_message(4),
+      ));
+    }
+
+    s
+  }
+
+  fn format_source_line(&self, level: usize) -> String {
+    if self.source_line.is_none() {
+      return "".to_string();
+    }
+
+    let source_line = self.source_line.as_ref().unwrap();
+    // sometimes source_line gets set with an empty string, which then outputs
+    // an empty source line when displayed, so need just short circuit here
+    if source_line.is_empty() {
+      return "".to_string();
+    }
+
+    assert!(self.line_number.is_some());
+    assert!(self.start_column.is_some());
+    assert!(self.end_column.is_some());
+    let line = (1 + self.line_number.unwrap()).to_string();
+    let line_color = ansi::black_on_white(line.to_string());
+    let line_len = line.clone().len();
+    let line_padding =
+      ansi::black_on_white(format!("{:indent$}", "", indent = line_len))
+        .to_string();
+    let mut s = String::new();
+    let start_column = self.start_column.unwrap();
+    let end_column = self.end_column.unwrap();
+    // TypeScript uses `~` always, but V8 would utilise `^` always, even when
+    // doing ranges, so here, if we only have one marker (very common with V8
+    // errors) we will use `^` instead.
+    let underline_char = if (end_column - start_column) <= 1 {
+      '^'
+    } else {
+      '~'
+    };
+    for i in 0..end_column {
+      if i >= start_column {
+        s.push(underline_char);
+      } else {
+        s.push(' ');
+      }
+    }
+    let color_underline = match self.category {
+      DiagnosticCategory::Error => ansi::red(s).to_string(),
+      _ => ansi::cyan(s).to_string(),
+    };
+
+    let indent = format!("{:indent$}", "", indent = level);
+
+    format!(
+      "\n\n{}{} {}\n{}{} {}\n",
+      indent, line_color, source_line, indent, line_padding, color_underline
+    )
+  }
+
+  fn format_source_name(&self, level: usize) -> String {
+    if self.script_resource_name.is_none() {
+      return "".to_string();
+    }
+
+    let script_name = ansi::cyan(self.script_resource_name.clone().unwrap());
+    assert!(self.line_number.is_some());
+    assert!(self.start_column.is_some());
+    let line = ansi::yellow((1 + self.line_number.unwrap()).to_string());
+    let column = ansi::yellow((1 + self.start_column.unwrap()).to_string());
+    format!(
+      "{:indent$}{}:{}:{} ",
+      "",
+      script_name,
+      line,
+      column,
+      indent = level
+    )
+  }
+}
+
+impl fmt::Display for DiagnosticItem {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    write!(
+      f,
+      "{}{}{}{}{}",
+      self.format_source_name(0),
+      self.format_category_and_code(),
+      self.format_message(0),
+      self.format_source_line(0),
+      self.format_related_info(),
+    )?;
+
+    Ok(())
+  }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct DiagnosticMessageChain {
+  pub message: String,
+  pub code: i64,
+  pub category: DiagnosticCategory,
+  pub next: Option<Box<DiagnosticMessageChain>>,
+}
+
+impl DiagnosticMessageChain {
+  pub fn from_json_value(v: &serde_json::Value) -> Option<Box<Self>> {
+    if !v.is_object() {
+      return None;
+    }
+
+    let obj = v.as_object().unwrap();
+    let message = obj
+      .get("message")
+      .and_then(|v| v.as_str().map(String::from))
+      .unwrap();
+    let code = obj.get("code").and_then(Value::as_i64).unwrap();
+    let category = DiagnosticCategory::from(
+      obj.get("category").and_then(Value::as_i64).unwrap(),
+    );
+
+    let next_v = obj.get("next");
+    let next = match next_v {
+      Some(n) => DiagnosticMessageChain::from_json_value(n),
+      _ => None,
+    };
+
+    Some(Box::new(Self {
+      message,
+      code,
+      category,
+      next,
+    }))
+  }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum DiagnosticCategory {
+  Log,        // 0
+  Debug,      // 1
+  Info,       // 2
+  Error,      // 3
+  Warning,    // 4
+  Suggestion, // 5
+}
+
+impl From<i64> for DiagnosticCategory {
+  fn from(value: i64) -> Self {
+    match value {
+      0 => DiagnosticCategory::Log,
+      1 => DiagnosticCategory::Debug,
+      2 => DiagnosticCategory::Info,
+      3 => DiagnosticCategory::Error,
+      4 => DiagnosticCategory::Warning,
+      5 => DiagnosticCategory::Suggestion,
+      _ => panic!("Unknown value: {}", value),
+    }
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use crate::ansi::strip_ansi_codes;
+
+  fn diagnostic1() -> Diagnostic {
+    Diagnostic {
+      items: vec![
+        DiagnosticItem {
+          message: "Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.".to_string(),
+          message_chain: Some(Box::new(DiagnosticMessageChain {
+            message: "Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.".to_string(),
+            code: 2322,
+            category: DiagnosticCategory::Error,
+            next: Some(Box::new(DiagnosticMessageChain {
+              message: "Types of parameters 'o' and 'r' are incompatible.".to_string(),
+              code: 2328,
+              category: DiagnosticCategory::Error,
+              next: Some(Box::new(DiagnosticMessageChain {
+                message: "Type 'B' is not assignable to type 'T'.".to_string(),
+                code: 2322,
+                category: DiagnosticCategory::Error,
+                next: None,
+              })),
+            })),
+          })),
+          code: 2322,
+          category: DiagnosticCategory::Error,
+          start_position: Some(267),
+          end_position: Some(273),
+          source_line: Some("  values: o => [".to_string()),
+          line_number: Some(18),
+          script_resource_name: Some("deno/tests/complex_diagnostics.ts".to_string()),
+          start_column: Some(2),
+          end_column: Some(8),
+          related_information: Some(vec![
+            DiagnosticItem {
+              message: "The expected type comes from property 'values' which is declared here on type 'SettingsInterface<B>'".to_string(),
+              message_chain: None,
+              related_information: None,
+              code: 6500,
+              source_line: Some("  values?: (r: T) => Array<Value<T>>;".to_string()),
+              script_resource_name: Some("deno/tests/complex_diagnostics.ts".to_string()),
+              line_number: Some(6),
+              start_position: Some(94),
+              end_position: Some(100),
+              category: DiagnosticCategory::Info,
+              start_column: Some(2),
+              end_column: Some(8),
+            }
+          ])
+        }
+      ]
+    }
+  }
+
+  fn diagnostic2() -> Diagnostic {
+    Diagnostic {
+      items: vec![
+        DiagnosticItem {
+          message: "Example 1".to_string(),
+          message_chain: None,
+          code: 2322,
+          category: DiagnosticCategory::Error,
+          start_position: Some(267),
+          end_position: Some(273),
+          source_line: Some("  values: o => [".to_string()),
+          line_number: Some(18),
+          script_resource_name: Some(
+            "deno/tests/complex_diagnostics.ts".to_string(),
+          ),
+          start_column: Some(2),
+          end_column: Some(8),
+          related_information: None,
+        },
+        DiagnosticItem {
+          message: "Example 2".to_string(),
+          message_chain: None,
+          code: 2000,
+          category: DiagnosticCategory::Error,
+          start_position: Some(2),
+          end_position: Some(2),
+          source_line: Some("  values: undefined,".to_string()),
+          line_number: Some(128),
+          script_resource_name: Some("/foo/bar.ts".to_string()),
+          start_column: Some(2),
+          end_column: Some(8),
+          related_information: None,
+        },
+      ],
+    }
+  }
+
+  #[test]
+  fn from_json() {
+    let v = serde_json::from_str::<serde_json::Value>(
+      &r#"{
+        "items": [
+          {
+            "message": "Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.",
+            "messageChain": {
+              "message": "Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.",
+              "code": 2322,
+              "category": 3,
+              "next": {
+                "message": "Types of parameters 'o' and 'r' are incompatible.",
+                "code": 2328,
+                "category": 3,
+                "next": {
+                  "message": "Type 'B' is not assignable to type 'T'.",
+                  "code": 2322,
+                  "category": 3
+                }
+              }
+            },
+            "code": 2322,
+            "category": 3,
+            "startPosition": 235,
+            "endPosition": 241,
+            "sourceLine": "  values: o => [",
+            "lineNumber": 18,
+            "scriptResourceName": "/deno/tests/complex_diagnostics.ts",
+            "startColumn": 2,
+            "endColumn": 8,
+            "relatedInformation": [
+              {
+                "message": "The expected type comes from property 'values' which is declared here on type 'C<B>'",
+                "code": 6500,
+                "category": 2,
+                "startPosition": 78,
+                "endPosition": 84,
+                "sourceLine": "  values?: (r: T) => Array<Value<T>>;",
+                "lineNumber": 6,
+                "scriptResourceName": "/deno/tests/complex_diagnostics.ts",
+                "startColumn": 2,
+                "endColumn": 8
+              }
+            ]
+          },
+          {
+            "message": "Property 't' does not exist on type 'T'.",
+            "code": 2339,
+            "category": 3,
+            "startPosition": 267,
+            "endPosition": 268,
+            "sourceLine": "      v: o.t,",
+            "lineNumber": 20,
+            "scriptResourceName": "/deno/tests/complex_diagnostics.ts",
+            "startColumn": 11,
+            "endColumn": 12
+          }
+        ]
+      }"#,
+    ).unwrap();
+    let r = Diagnostic::from_json_value(&v);
+    let expected = Some(Diagnostic {
+      items: vec![
+        DiagnosticItem {
+          message: "Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.".to_string(),
+          message_chain: Some(Box::new(DiagnosticMessageChain {
+            message: "Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.".to_string(),
+            code: 2322,
+            category: DiagnosticCategory::Error,
+            next: Some(Box::new(DiagnosticMessageChain {
+              message: "Types of parameters 'o' and 'r' are incompatible.".to_string(),
+              code: 2328,
+              category: DiagnosticCategory::Error,
+              next: Some(Box::new(DiagnosticMessageChain {
+                message: "Type 'B' is not assignable to type 'T'.".to_string(),
+                code: 2322,
+                category: DiagnosticCategory::Error,
+                next: None,
+              })),
+            })),
+          })),
+          related_information: Some(vec![
+            DiagnosticItem {
+              message: "The expected type comes from property 'values' which is declared here on type 'C<B>'".to_string(),
+              message_chain: None,
+              related_information: None,
+              source_line: Some("  values?: (r: T) => Array<Value<T>>;".to_string()),
+              line_number: Some(6),
+              script_resource_name: Some("/deno/tests/complex_diagnostics.ts".to_string()),
+              start_position: Some(78),
+              end_position: Some(84),
+              category: DiagnosticCategory::Info,
+              code: 6500,
+              start_column: Some(2),
+              end_column: Some(8),
+            }
+          ]),
+          source_line: Some("  values: o => [".to_string()),
+          line_number: Some(18),
+          script_resource_name: Some("/deno/tests/complex_diagnostics.ts".to_string()),
+          start_position: Some(235),
+          end_position: Some(241),
+          category: DiagnosticCategory::Error,
+          code: 2322,
+          start_column: Some(2),
+          end_column: Some(8),
+        },
+        DiagnosticItem {
+          message: "Property 't' does not exist on type 'T'.".to_string(),
+          message_chain: None,
+          related_information: None,
+          source_line: Some("      v: o.t,".to_string()),
+          line_number: Some(20),
+          script_resource_name: Some("/deno/tests/complex_diagnostics.ts".to_string()),
+          start_position: Some(267),
+          end_position: Some(268),
+          category: DiagnosticCategory::Error,
+          code: 2339,
+          start_column: Some(11),
+          end_column: Some(12),
+        },
+      ],
+    });
+    assert_eq!(expected, r);
+  }
+
+  #[test]
+  fn from_emit_result() {
+    let r = Diagnostic::from_emit_result(
+      &r#"{
+      "emitSkipped": false,
+      "diagnostics": {
+        "items": [
+          {
+            "message": "foo bar",
+            "code": 9999,
+            "category": 3
+          }
+        ]
+      }
+    }"#,
+    );
+    let expected = Some(Diagnostic {
+      items: vec![DiagnosticItem {
+        message: "foo bar".to_string(),
+        message_chain: None,
+        related_information: None,
+        source_line: None,
+        line_number: None,
+        script_resource_name: None,
+        start_position: None,
+        end_position: None,
+        category: DiagnosticCategory::Error,
+        code: 9999,
+        start_column: None,
+        end_column: None,
+      }],
+    });
+    assert_eq!(expected, r);
+  }
+
+  #[test]
+  fn from_emit_result_none() {
+    let r = &r#"{"emitSkipped":false}"#;
+    assert!(Diagnostic::from_emit_result(r).is_none());
+  }
+
+  #[test]
+  fn diagnostic_to_string1() {
+    let d = diagnostic1();
+    let expected = "deno/tests/complex_diagnostics.ts:19:3 - error TS2322: Type \'(o: T) => { v: any; f: (x: B) => string; }[]\' is not assignable to type \'(r: B) => Value<B>[]\'.\n  Types of parameters \'o\' and \'r\' are incompatible.\n    Type \'B\' is not assignable to type \'T\'.\n\n19   values: o => [\n     ~~~~~~\n\n  deno/tests/complex_diagnostics.ts:7:3 \n\n    7   values?: (r: T) => Array<Value<T>>;\n        ~~~~~~\n    The expected type comes from property \'values\' which is declared here on type \'SettingsInterface<B>\'\n";
+    assert_eq!(expected, strip_ansi_codes(&d.to_string()));
+  }
+
+  #[test]
+  fn diagnostic_to_string2() {
+    let d = diagnostic2();
+    let expected = "deno/tests/complex_diagnostics.ts:19:3 - error TS2322: Example 1\n\n19   values: o => [\n     ~~~~~~\n\n/foo/bar.ts:129:3 - error TS2000: Example 2\n\n129   values: undefined,\n      ~~~~~~\n\n\nFound 2 errors.\n";
+    assert_eq!(expected, strip_ansi_codes(&d.to_string()));
+  }
+}
diff --git a/cli/main.rs b/cli/main.rs
index 5d70805ae..953e01943 100644
--- a/cli/main.rs
+++ b/cli/main.rs
@@ -16,6 +16,7 @@ extern crate rand;
 mod ansi;
 pub mod compiler;
 pub mod deno_dir;
+pub mod diagnostics;
 mod dispatch_minimal;
 pub mod errors;
 pub mod flags;
diff --git a/cli/worker.rs b/cli/worker.rs
index 59eecda6f..c08a43385 100644
--- a/cli/worker.rs
+++ b/cli/worker.rs
@@ -4,7 +4,6 @@ use crate::compiler::ModuleMetaData;
 use crate::errors::DenoError;
 use crate::errors::RustOrJsError;
 use crate::js_errors;
-use crate::js_errors::JSErrorColor;
 use crate::msg;
 use crate::state::ThreadSafeState;
 use crate::tokio_util;
@@ -233,7 +232,7 @@ fn fetch_module_meta_data_and_maybe_compile_async(
             compile_async(state_.clone(), &specifier, &referrer, &out)
               .map_err(|e| {
                 debug!("compiler error exiting!");
-                eprintln!("{}", JSErrorColor(&e).to_string());
+                eprintln!("\n{}", e.to_string());
                 std::process::exit(1);
               }).and_then(move |out| {
                 debug!(">>>>> compile_sync END");
diff --git a/js/compiler.ts b/js/compiler.ts
index 15adba746..6b0881700 100644
--- a/js/compiler.ts
+++ b/js/compiler.ts
@@ -1,6 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/cli/msg_generated";
 import { core } from "./core";
+import { Diagnostic, fromTypeScriptDiagnostic } from "./diagnostics";
 import * as flatbuffers from "./flatbuffers";
 import { sendSync } from "./dispatch";
 import { TextDecoder } from "./text_encoding";
@@ -37,6 +38,11 @@ interface CompilerReq {
   config?: string;
 }
 
+interface ConfigureResponse {
+  ignoredOptions?: string[];
+  diagnostics?: ts.Diagnostic[];
+}
+
 /** Options that either do nothing in Deno, or would cause undesired behavior
  * if modified. */
 const ignoredCompilerOptions: ReadonlyArray<string> = [
@@ -105,6 +111,11 @@ interface ModuleMetaData {
   sourceCode: string | undefined;
 }
 
+interface EmitResult {
+  emitSkipped: boolean;
+  diagnostics?: Diagnostic;
+}
+
 function fetchModuleMetaData(
   specifier: string,
   referrer: string
@@ -193,22 +204,19 @@ class Host implements ts.CompilerHost {
    * compiler's configuration options.  The method returns an array of compiler
    * options which were ignored, or `undefined`.
    */
-  configure(path: string, configurationText: string): string[] | undefined {
+  configure(path: string, configurationText: string): ConfigureResponse {
     util.log("compile.configure", path);
     const { config, error } = ts.parseConfigFileTextToJson(
       path,
       configurationText
     );
     if (error) {
-      this._logDiagnostics([error]);
+      return { diagnostics: [error] };
     }
     const { options, errors } = ts.convertCompilerOptionsFromJson(
       config.compilerOptions,
       cwd()
     );
-    if (errors.length) {
-      this._logDiagnostics(errors);
-    }
     const ignoredOptions: string[] = [];
     for (const key of Object.keys(options)) {
       if (
@@ -220,7 +228,10 @@ class Host implements ts.CompilerHost {
       }
     }
     Object.assign(this._options, options);
-    return ignoredOptions.length ? ignoredOptions : undefined;
+    return {
+      ignoredOptions: ignoredOptions.length ? ignoredOptions : undefined,
+      diagnostics: errors.length ? errors : undefined
+    };
   }
 
   getCompilationSettings(): ts.CompilerOptions {
@@ -228,19 +239,6 @@ class Host implements ts.CompilerHost {
     return this._options;
   }
 
-  /** Log TypeScript diagnostics to the console and exit */
-  _logDiagnostics(diagnostics: ReadonlyArray<ts.Diagnostic>): never {
-    const errMsg = os.noColor
-      ? ts.formatDiagnostics(diagnostics, this)
-      : ts.formatDiagnosticsWithColorAndContext(diagnostics, this);
-
-    console.log(errMsg);
-    // TODO The compiler isolate shouldn't call os.exit(). (In fact, it
-    // shouldn't even have access to call that op.) Errors should be forwarded
-    // to to the caller and the caller exit.
-    return os.exit(1);
-  }
-
   fileExists(_fileName: string): boolean {
     return notImplemented();
   }
@@ -362,10 +360,17 @@ class Host implements ts.CompilerHost {
 window.compilerMain = function compilerMain(): void {
   // workerMain should have already been called since a compiler is a worker.
   window.onmessage = ({ data }: { data: CompilerReq }): void => {
+    let emitSkipped = true;
+    let diagnostics: ts.Diagnostic[] | undefined;
+
     const { rootNames, configPath, config } = data;
     const host = new Host();
-    if (config && config.length) {
-      const ignoredOptions = host.configure(configPath!, config);
+
+    // if there is a configuration supplied, we need to parse that
+    if (config && config.length && configPath) {
+      const configResult = host.configure(configPath, config);
+      const ignoredOptions = configResult.ignoredOptions;
+      diagnostics = configResult.diagnostics;
       if (ignoredOptions) {
         console.warn(
           yellow(`Unsupported compiler options in "${configPath}"\n`) +
@@ -377,51 +382,52 @@ window.compilerMain = function compilerMain(): void {
       }
     }
 
-    const options = host.getCompilationSettings();
-    const program = ts.createProgram(rootNames, options, host);
-
-    const preEmitDiagnostics = ts.getPreEmitDiagnostics(program).filter(
-      ({ code }): boolean => {
-        // TS2691: An import path cannot end with a '.ts' extension. Consider
-        // importing 'bad-module' instead.
-        if (code === 2691) return false;
-        // TS5009: Cannot find the common subdirectory path for the input files.
-        if (code === 5009) return false;
-        // TS5055: Cannot write file
-        // 'http://localhost:4545/tests/subdir/mt_application_x_javascript.j4.js'
-        // because it would overwrite input file.
-        if (code === 5055) return false;
-        // TypeScript is overly opinionated that only CommonJS modules kinds can
-        // support JSON imports.  Allegedly this was fixed in
-        // Microsoft/TypeScript#26825 but that doesn't seem to be working here,
-        // so we will ignore complaints about this compiler setting.
-        if (code === 5070) return false;
-        return true;
+    // if there was a configuration and no diagnostics with it, we will continue
+    // to generate the program and possibly emit it.
+    if (!diagnostics || (diagnostics && diagnostics.length === 0)) {
+      const options = host.getCompilationSettings();
+      const program = ts.createProgram(rootNames, options, host);
+
+      diagnostics = ts.getPreEmitDiagnostics(program).filter(
+        ({ code }): boolean => {
+          // TS2691: An import path cannot end with a '.ts' extension. Consider
+          // importing 'bad-module' instead.
+          if (code === 2691) return false;
+          // TS5009: Cannot find the common subdirectory path for the input files.
+          if (code === 5009) return false;
+          // TS5055: Cannot write file
+          // 'http://localhost:4545/tests/subdir/mt_application_x_javascript.j4.js'
+          // because it would overwrite input file.
+          if (code === 5055) return false;
+          // TypeScript is overly opinionated that only CommonJS modules kinds can
+          // support JSON imports.  Allegedly this was fixed in
+          // Microsoft/TypeScript#26825 but that doesn't seem to be working here,
+          // so we will ignore complaints about this compiler setting.
+          if (code === 5070) return false;
+          return true;
+        }
+      );
+
+      // We will only proceed with the emit if there are no diagnostics.
+      if (diagnostics && diagnostics.length === 0) {
+        const emitResult = program.emit();
+        emitSkipped = emitResult.emitSkipped;
+        // emitResult.diagnostics is `readonly` in TS3.5+ and can't be assigned
+        // without casting.
+        diagnostics = emitResult.diagnostics as ts.Diagnostic[];
       }
-    );
-    if (preEmitDiagnostics.length > 0) {
-      host._logDiagnostics(preEmitDiagnostics);
-      // The above _logDiagnostics calls os.exit(). The return is here just for
-      // clarity.
-      return;
     }
 
-    const emitResult = program!.emit();
-
-    // TODO(ry) Print diagnostics in Rust.
-    // https://github.com/denoland/deno/pull/2310
-
-    const { diagnostics } = emitResult;
-    if (diagnostics.length > 0) {
-      host._logDiagnostics(diagnostics);
-      // The above _logDiagnostics calls os.exit(). The return is here just for
-      // clarity.
-      return;
-    }
+    const result: EmitResult = {
+      emitSkipped,
+      diagnostics: diagnostics.length
+        ? fromTypeScriptDiagnostic(diagnostics)
+        : undefined
+    };
 
-    postMessage(emitResult);
+    postMessage(result);
 
-    // The compiler isolate exits after a single messsage.
+    // The compiler isolate exits after a single message.
     workerClose();
   };
 };
diff --git a/js/diagnostics.ts b/js/diagnostics.ts
new file mode 100644
index 000000000..1207eca4f
--- /dev/null
+++ b/js/diagnostics.ts
@@ -0,0 +1,218 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+// Diagnostic provides an abstraction for advice/errors received from a
+// compiler, which is strongly influenced by the format of TypeScript
+// diagnostics.
+
+import * as ts from "typescript";
+
+/** The log category for a diagnostic message */
+export enum DiagnosticCategory {
+  Log = 0,
+  Debug = 1,
+  Info = 2,
+  Error = 3,
+  Warning = 4,
+  Suggestion = 5
+}
+
+export interface DiagnosticMessageChain {
+  message: string;
+  category: DiagnosticCategory;
+  code: number;
+  next?: DiagnosticMessageChain;
+}
+
+export interface DiagnosticItem {
+  /** A string message summarizing the diagnostic. */
+  message: string;
+
+  /** An ordered array of further diagnostics. */
+  messageChain?: DiagnosticMessageChain;
+
+  /** Information related to the diagnostic.  This is present when there is a
+   * suggestion or other additional diagnostic information */
+  relatedInformation?: DiagnosticItem[];
+
+  /** The text of the source line related to the diagnostic */
+  sourceLine?: string;
+
+  /** The line number that is related to the diagnostic */
+  lineNumber?: number;
+
+  /** The name of the script resource related to the diagnostic */
+  scriptResourceName?: string;
+
+  /** The start position related to the diagnostic */
+  startPosition?: number;
+
+  /** The end position related to the diagnostic */
+  endPosition?: number;
+
+  /** The category of the diagnostic */
+  category: DiagnosticCategory;
+
+  /** A number identifier */
+  code: number;
+
+  /** The the start column of the sourceLine related to the diagnostic */
+  startColumn?: number;
+
+  /** The end column of the sourceLine related to the diagnostic */
+  endColumn?: number;
+}
+
+export interface Diagnostic {
+  /** An array of diagnostic items. */
+  items: DiagnosticItem[];
+}
+
+interface SourceInformation {
+  sourceLine: string;
+  lineNumber: number;
+  scriptResourceName: string;
+  startColumn: number;
+  endColumn: number;
+}
+
+function fromDiagnosticCategory(
+  category: ts.DiagnosticCategory
+): DiagnosticCategory {
+  switch (category) {
+    case ts.DiagnosticCategory.Error:
+      return DiagnosticCategory.Error;
+    case ts.DiagnosticCategory.Message:
+      return DiagnosticCategory.Info;
+    case ts.DiagnosticCategory.Suggestion:
+      return DiagnosticCategory.Suggestion;
+    case ts.DiagnosticCategory.Warning:
+      return DiagnosticCategory.Warning;
+    default:
+      throw new Error(
+        `Unexpected DiagnosticCategory: "${category}"/"${
+          ts.DiagnosticCategory[category]
+        }"`
+      );
+  }
+}
+
+function getSourceInformation(
+  sourceFile: ts.SourceFile,
+  start: number,
+  length: number
+): SourceInformation {
+  const scriptResourceName = sourceFile.fileName;
+  const {
+    line: lineNumber,
+    character: startColumn
+  } = sourceFile.getLineAndCharacterOfPosition(start);
+  const endPosition = sourceFile.getLineAndCharacterOfPosition(start + length);
+  const endColumn =
+    lineNumber === endPosition.line ? endPosition.character : startColumn;
+  const lastLineInFile = sourceFile.getLineAndCharacterOfPosition(
+    sourceFile.text.length
+  ).line;
+  const lineStart = sourceFile.getPositionOfLineAndCharacter(lineNumber, 0);
+  const lineEnd =
+    lineNumber < lastLineInFile
+      ? sourceFile.getPositionOfLineAndCharacter(lineNumber + 1, 0)
+      : sourceFile.text.length;
+  const sourceLine = sourceFile.text
+    .slice(lineStart, lineEnd)
+    .replace(/\s+$/g, "")
+    .replace("\t", " ");
+  return {
+    sourceLine,
+    lineNumber,
+    scriptResourceName,
+    startColumn,
+    endColumn
+  };
+}
+
+/** Converts a TypeScript diagnostic message chain to a Deno one. */
+function fromDiagnosticMessageChain(
+  messageChain: ts.DiagnosticMessageChain | undefined
+): DiagnosticMessageChain | undefined {
+  if (!messageChain) {
+    return undefined;
+  }
+
+  const { messageText: message, code, category, next } = messageChain;
+  return {
+    message,
+    code,
+    category: fromDiagnosticCategory(category),
+    next: fromDiagnosticMessageChain(next)
+  };
+}
+
+/** Parse out information from a TypeScript diagnostic structure. */
+function parseDiagnostic(
+  item: ts.Diagnostic | ts.DiagnosticRelatedInformation
+): DiagnosticItem {
+  const {
+    messageText,
+    category: sourceCategory,
+    code,
+    file,
+    start: startPosition,
+    length
+  } = item;
+  const sourceInfo =
+    file && startPosition && length
+      ? getSourceInformation(file, startPosition, length)
+      : undefined;
+  const endPosition =
+    startPosition && length ? startPosition + length : undefined;
+  const category = fromDiagnosticCategory(sourceCategory);
+
+  let message: string;
+  let messageChain: DiagnosticMessageChain | undefined;
+  if (typeof messageText === "string") {
+    message = messageText;
+  } else {
+    message = messageText.messageText;
+    messageChain = fromDiagnosticMessageChain(messageText);
+  }
+
+  const base = {
+    message,
+    messageChain,
+    code,
+    category,
+    startPosition,
+    endPosition
+  };
+
+  return sourceInfo ? { ...base, ...sourceInfo } : base;
+}
+
+/** Convert a diagnostic related information array into a Deno diagnostic
+ * array. */
+function parseRelatedInformation(
+  relatedInformation: readonly ts.DiagnosticRelatedInformation[]
+): DiagnosticItem[] {
+  const result: DiagnosticItem[] = [];
+  for (const item of relatedInformation) {
+    result.push(parseDiagnostic(item));
+  }
+  return result;
+}
+
+/** Convert TypeScript diagnostics to Deno diagnostics. */
+export function fromTypeScriptDiagnostic(
+  diagnostics: readonly ts.Diagnostic[]
+): Diagnostic {
+  let items: DiagnosticItem[] = [];
+  for (const sourceDiagnostic of diagnostics) {
+    const item: DiagnosticItem = parseDiagnostic(sourceDiagnostic);
+    if (sourceDiagnostic.relatedInformation) {
+      item.relatedInformation = parseRelatedInformation(
+        sourceDiagnostic.relatedInformation
+      );
+    }
+    items.push(item);
+  }
+  return { items };
+}
diff --git a/package.json b/package.json
index 7ac027447..8f87d4229 100644
--- a/package.json
+++ b/package.json
@@ -12,7 +12,7 @@
     "eslint-config-prettier": "4.1.0",
     "flatbuffers": "1.9.0",
     "magic-string": "0.25.2",
-    "prettier": "1.16.4",
+    "prettier": "1.17.1",
     "rollup": "1.4.1",
     "rollup-plugin-alias": "1.5.1",
     "rollup-plugin-analyzer": "3.0.0",
diff --git a/rollup.config.js b/rollup.config.js
index 635aace0d..41f738bae 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -239,6 +239,7 @@ export default function makeConfig(commandOptions) {
             "parseConfigFileTextToJson",
             "version",
             "CompilerHost",
+            "DiagnosticCategory",
             "Extension",
             "ModuleKind",
             "ScriptKind",
diff --git a/tests/013_dynamic_import.ts b/tests/013_dynamic_import.ts
index 20dc508db..6bbce3132 100644
--- a/tests/013_dynamic_import.ts
+++ b/tests/013_dynamic_import.ts
@@ -1,9 +1,7 @@
 (async (): Promise<void> => {
-  const {
-    returnsHi,
-    returnsFoo2,
-    printHello3
-  } = await import("./subdir/mod1.ts");
+  const { returnsHi, returnsFoo2, printHello3 } = await import(
+    "./subdir/mod1.ts"
+  );
 
   printHello3();
 
diff --git a/tests/error_003_typescript.test b/tests/error_003_typescript.test
index f721829a2..a7a68627a 100644
--- a/tests/error_003_typescript.test
+++ b/tests/error_003_typescript.test
@@ -1,3 +1,4 @@
 args: run --reload tests/error_003_typescript.ts
+check_stderr: true
 exit_code: 1
 output: tests/error_003_typescript.ts.out
diff --git a/tests/error_003_typescript.ts b/tests/error_003_typescript.ts
index ebd9fcbe6..6fb077ea0 100644
--- a/tests/error_003_typescript.ts
+++ b/tests/error_003_typescript.ts
@@ -1,2 +1,26 @@
-// console.log intentionally misspelled to trigger TypeScript error
-consol.log("hello world!");
+/* eslint-disable */
+interface Value<T> {
+  f?: (r: T) => any;
+  v?: string;
+}
+
+interface C<T> {
+  values?: (r: T) => Array<Value<T>>;
+}
+
+class A<T> {
+  constructor(private e?: T, public s?: C<T>) {}
+}
+
+class B {
+  t = "foo";
+}
+
+var a = new A(new B(), {
+  values: o => [
+    {
+      v: o.t,
+      f: x => "bar"
+    }
+  ]
+});
diff --git a/tests/error_003_typescript.ts.out b/tests/error_003_typescript.ts.out
index 65bc33591..e2efd5639 100644
--- a/tests/error_003_typescript.ts.out
+++ b/tests/error_003_typescript.ts.out
@@ -1,10 +1,22 @@
-[WILDCARD]tests/error_003_typescript.ts[WILDCARD] - error TS2552: Cannot find name 'consol'. Did you mean 'console'?
+[WILDCARD]/tests/error_003_typescript.ts:20:3 - error TS2322: Type '(o: T) => { v: any; f: (x: B) => string; }[]' is not assignable to type '(r: B) => Value<B>[]'.
+  Types of parameters 'o' and 'r' are incompatible.
+    Type 'B' is not assignable to type 'T'.
+      'B' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint '{}'.
 
-[WILDCARD] consol.log("hello world!");
-[WILDCARD]~~~~~~
+20   values: o => [
+     ~~~~~~
 
-  $asset$/lib.deno_runtime.d.ts[WILDCARD]
-[WILDCARD]declare const console: consoleTypes.Console;
-[WILDCARD]~~~~~~~
-[WILDCARD]'console' is declared here.
+  [WILDCARD]/tests/error_003_typescript.ts:8:3 
+
+    8   values?: (r: T) => Array<Value<T>>;
+        ~~~~~~
+    The expected type comes from property 'values' which is declared here on type 'C<B>'
+
+[WILDCARD]/tests/error_003_typescript.ts:22:12 - error TS2339: Property 't' does not exist on type 'T'.
+
+22       v: o.t,
+              ^
+
+
+Found 2 errors.
 
diff --git a/tests/error_003_typescript2.test b/tests/error_003_typescript2.test
index 62e66d7e7..c4c724259 100644
--- a/tests/error_003_typescript2.test
+++ b/tests/error_003_typescript2.test
@@ -3,5 +3,6 @@
 # should result in the same output.
 # https://github.com/denoland/deno/issues/2436
 args: run tests/error_003_typescript.ts
+check_stderr: true
 exit_code: 1
 output: tests/error_003_typescript.ts.out
diff --git a/third_party b/third_party
-Subproject 0761d3cee6dd43c38f676268b496a37527fc9ba
+Subproject 72a4202a0341516115a92aa18951eb3010fb75f