From 2ef462a75f9e49b58a7dd64713743ec43d9d47bd Mon Sep 17 00:00:00 2001
From: Paul Jolly <paul@myitcv.org.uk>
Date: Wed, 16 Nov 2016 16:54:43 +0000
Subject: [PATCH] Use import name if set else package name when qualifying
 types

---
 suggest/candidate.go                    | 22 +++++++++++++++++++++
 suggest/suggest.go                      |  9 +++++----
 suggest/testdata/test.0065/out.expected | 26 +++++++++++++++++++++++++
 suggest/testdata/test.0065/test.go.in   |  8 ++++++++
 4 files changed, 61 insertions(+), 4 deletions(-)
 create mode 100644 suggest/testdata/test.0065/out.expected
 create mode 100644 suggest/testdata/test.0065/test.go.in

diff --git a/suggest/candidate.go b/suggest/candidate.go
index 48328c42..d884e79e 100644
--- a/suggest/candidate.go
+++ b/suggest/candidate.go
@@ -2,6 +2,7 @@ package suggest
 
 import (
 	"fmt"
+	"go/ast"
 	"go/types"
 	"sort"
 	"strings"
@@ -78,6 +79,7 @@ type candidateCollector struct {
 	candidates []Candidate
 	exact      []types.Object
 	badcase    []types.Object
+	imports    []*ast.ImportSpec
 	localpkg   *types.Package
 	partial    string
 	filter     objectFilter
@@ -157,6 +159,26 @@ func (b *candidateCollector) qualify(pkg *types.Package) string {
 	if pkg == b.localpkg {
 		return ""
 	}
+
+	// the *types.Package we are asked to qualify might _not_ be imported
+	// by the file in which we are asking for candidates. Hence... we retain
+	// the default of pkg.Name() as the qualifier
+
+	for _, i := range b.imports {
+		// given the import spec has been correctly parsed (by virtue of
+		// its existence) we can safely byte-index the path value knowing
+		// that len("\"") == 1
+		iPath := i.Path.Value[1 : len(i.Path.Value)-1]
+
+		if iPath == pkg.Path() {
+			if i.Name != nil && i.Name.Name != "." {
+				return i.Name.Name
+			} else {
+				return pkg.Name()
+			}
+		}
+	}
+
 	return pkg.Name()
 }
 
diff --git a/suggest/suggest.go b/suggest/suggest.go
index 7d9ddf73..4bf8e586 100644
--- a/suggest/suggest.go
+++ b/suggest/suggest.go
@@ -26,7 +26,7 @@ func (c *Config) Suggest(filename string, data []byte, cursor int) ([]Candidate,
 		return nil, 0
 	}
 
-	fset, pos, pkg := c.analyzePackage(filename, data, cursor)
+	fset, pos, pkg, imports := c.analyzePackage(filename, data, cursor)
 	if pkg == nil {
 		return nil, 0
 	}
@@ -35,6 +35,7 @@ func (c *Config) Suggest(filename string, data []byte, cursor int) ([]Candidate,
 	ctx, expr, partial := deduceCursorContext(data, cursor)
 	b := candidateCollector{
 		localpkg: pkg,
+		imports:  imports,
 		partial:  partial,
 		filter:   objectFilters[partial],
 	}
@@ -75,7 +76,7 @@ func (c *Config) Suggest(filename string, data []byte, cursor int) ([]Candidate,
 	return res, len(partial)
 }
 
-func (c *Config) analyzePackage(filename string, data []byte, cursor int) (*token.FileSet, token.Pos, *types.Package) {
+func (c *Config) analyzePackage(filename string, data []byte, cursor int) (*token.FileSet, token.Pos, *types.Package, []*ast.ImportSpec) {
 	// If we're in trailing white space at the end of a scope,
 	// sometimes go/types doesn't recognize that variables should
 	// still be in scope there.
@@ -88,7 +89,7 @@ func (c *Config) analyzePackage(filename string, data []byte, cursor int) (*toke
 	}
 	astPos := fileAST.Pos()
 	if astPos == 0 {
-		return nil, token.NoPos, nil
+		return nil, token.NoPos, nil, nil
 	}
 	pos := fset.File(astPos).Pos(cursor)
 
@@ -118,7 +119,7 @@ func (c *Config) analyzePackage(filename string, data []byte, cursor int) (*toke
 	}
 	pkg, _ := cfg.Check("", fset, files, nil)
 
-	return fset, pos, pkg
+	return fset, pos, pkg, fileAST.Imports
 }
 
 func (c *Config) fieldNameCandidates(typ types.Type, b *candidateCollector) {
diff --git a/suggest/testdata/test.0065/out.expected b/suggest/testdata/test.0065/out.expected
new file mode 100644
index 00000000..040ba3c3
--- /dev/null
+++ b/suggest/testdata/test.0065/out.expected
@@ -0,0 +1,26 @@
+Found 25 candidates:
+  func Errorf(format string, a ...interface{}) error
+  func Fprint(w banana.Writer, a ...interface{}) (n int, err error)
+  func Fprintf(w banana.Writer, format string, a ...interface{}) (n int, err error)
+  func Fprintln(w banana.Writer, a ...interface{}) (n int, err error)
+  func Fscan(r banana.Reader, a ...interface{}) (n int, err error)
+  func Fscanf(r banana.Reader, format string, a ...interface{}) (n int, err error)
+  func Fscanln(r banana.Reader, a ...interface{}) (n int, err error)
+  func Print(a ...interface{}) (n int, err error)
+  func Printf(format string, a ...interface{}) (n int, err error)
+  func Println(a ...interface{}) (n int, err error)
+  func Scan(a ...interface{}) (n int, err error)
+  func Scanf(format string, a ...interface{}) (n int, err error)
+  func Scanln(a ...interface{}) (n int, err error)
+  func Sprint(a ...interface{}) string
+  func Sprintf(format string, a ...interface{}) string
+  func Sprintln(a ...interface{}) string
+  func Sscan(str string, a ...interface{}) (n int, err error)
+  func Sscanf(str string, format string, a ...interface{}) (n int, err error)
+  func Sscanln(str string, a ...interface{}) (n int, err error)
+  type Formatter interface
+  type GoStringer interface
+  type ScanState interface
+  type Scanner interface
+  type State interface
+  type Stringer interface
diff --git a/suggest/testdata/test.0065/test.go.in b/suggest/testdata/test.0065/test.go.in
new file mode 100644
index 00000000..2120ae51
--- /dev/null
+++ b/suggest/testdata/test.0065/test.go.in
@@ -0,0 +1,8 @@
+package p
+
+import (
+	"fmt"
+	banana "io"
+)
+
+var _ = fmt.@